FUEL AND EMISSIONS SYSTEMS

• HEADINGS
  • Special Tools
  • General Troubleshooting Information
    • Intermittent Failures
    • Service information
    • Opens and Shorts
    • How to Use the HDS (Honda Diagnostic System)
    • HDS Clear Command
    • Scan Tool Clear Command
    • DTC Clear
    • ECM/PCM Reset
    • Crank (CKP) Pattern Clear/Crank (CKP) Pattern Learn
      • Clear/Learn Procedure (with the HDS)
      • Learn Procedure (without the HDS)
      • How to End a Troubleshooting Session (required after any troubleshooting)
    • How to Troubleshoot Circuits at the ECM/PCM Connectors
    • Updating the ECM/PCM
    • Substituting the ECM/PCM
    • OBD Status
  • DTC Troubleshooting Index
  • Symptom Troubleshooting Index
  • System Description
    • Electronic Control System
      • Self-Diagnosis
      • Fail-safe Function
      • MIL Bulb Check and Readiness Code Condition
      • Self Shut Down (SSD) Mode
      • ECM/PCM Electrical Connections
    • ECM/PCM Inputs and Outputs at Connector A (31P)
    • ECM/PCM Inputs and Outputs at Connector B (24P)
    • PCM Inputs and Outputs at Connector C (22P)
    • ECM/PCM Inputs and Outputs at Connector D (17P)
    • ECM/PCM Inputs and Outputs at Connector E (31P)
    • Vacuum Hose Routing
    • Vacuum Distribution
    • PGM-FI System
      • Air Conditioning (A/C) Compressor Clutch Relay
      • Air Fuel Ratio (A/F) Sensor
      • Barometric Pressure (BARO) Sensor
      • Camshaft Position (CMP) Sensor B
      • Crankshaft Position (CKP) Sensor
      • Engine Coolant Temperature (ECT) Sensor ('04-05 models)/Engine Coolant Temperature (ECT) Sensors 1 and 2 ('06-08 models)
      • Ignition Timing Control
      • Injector Timing and Duration
      • Intake Air Temperature (IAT) Sensor
      • Knock Sensor
      • Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness Codes)
      • Manifold Absolute Pressure (MAP) Sensor
      • Output Shaft (Countershaft) Speed Sensor
      • Secondary Heated Oxygen Sensor (Secondary HO2S)
    • Electronic Throttle Control System
      • Accelerator Pedal Position (APP) Sensor
      • Throttle Body
    • VTEC/VTC
      • VTC System
      • VTEC System
    • VTEC/VTC
      • System Diagram
      • Camshaft Position (CMP) Sensor A
    • Idle Control System
      • Brake Pedal Position Switch
      • Power Steering Pressure (PSP) Switch
    • Fuel Supply System
      • Fuel Cutoff Control
      • Fuel Pump Control
      • PGM-FI Main Relay 1 and 2
    • Intake Air System
      • Intake Air Bypass Control Thermal Valve
      • Resonator
    • Catalytic Converter System
      • Three Way Catalytic Converter (TWC)
    • Positive Crankcase Ventilation (PCV) System
    • Evaporative Emission (EVAP) Control System
      • EVAP Canister
      • EVAP Canister Purge Valve
      • Fuel Tank Pressure (FTP) Sensor
      • EVAP Canister Vent Shut Valve
    • Fuel Cap Warning Message ('06-08 models)
      • First drive cycle
      • To make the message go off (With the HDS)
        • Procedure
      • To make the message go off (Without the HDS) ('06-07 models)
        • Procedure
      • To make the message go off (Without the HDS) ('08 model)
        • Procedure
    • Electronic Throttle Control System Diagram
    • Evaporative Emission (EVAP) Control Diagram
    • ECM/PCM Circuit Diagram
  • How to Set Readiness Codes
    • Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness Codes)
    • Catalytic Converter Monitor and Readiness Code
      • Enable Criteria
      • Procedure
    • Evaporative Emission (EVAP) Control System Monitor and Readiness Code
      • Enable Criteria
      • Procedure
    • Air Fuel Ratio (A/F) Sensor Monitor and Readiness Code
      • Enable Criteria
      • Procedure
    • Air Fuel Ratio (A/F) Sensor Heater Monitor Readiness Code
      • Procedure
    • Misfire Monitor and Readiness Code
    • Fuel System Monitor and Readiness Code
    • Comprehensive Component Monitor and Readiness Code
• FIGURES
  • Fig. 1: Identifying Special Tools - Fuel And Emissions Systems
  • Fig. 2: Identifying Malfunction Indicator Lamp
  • Fig. 3: Locating Data Link Connector
  • Fig. 4: Locating Data Link Connector
  • Fig. 5: Connecting Backprobe Adapters To Stacking Patch Cords And Connect Cords To Digital Multimeter
  • Fig. 6: Disconnecting Connector And Probe Terminals From Terminal Side
  • Fig. 7: Locating Data Link Connector
  • Fig. 8: Locating Data Link Connector
  • Fig. 9: Locating Center Lower Covers (with Torque Specifications)
  • Fig. 10: ECM/PCM Electrical Connections Diagram (1 Of 5)
  • Fig. 11: ECM/PCM Electrical Connections Diagram (2 Of 5)
  • Fig. 12: ECM/PCM Electrical Connections Diagram (3 Of 5)
  • Fig. 13: ECM/PCM Electrical Connections Diagram (4 Of 5)
  • Fig. 14: ECM/PCM Electrical Connections Diagram (5 Of 5)
  • Fig. 15: Identifying ECM/PCM Inputs And Outputs At Connector A (31P)
  • Fig. 16: Identifying ECM/PCM Inputs And Outputs At Connector B (24P)
  • Fig. 17: Identifying PCM Inputs And Outputs At Connector C (22P)
  • Fig. 18: Identifying ECM/PCM Inputs And Outputs At Connector D (17P)
  • Fig. 19: Identifying ECM/PCM Inputs And Outputs At Connector E (31P)
  • Fig. 20: Identifying Vacuum Hose Routing
  • Fig. 21: Identifying Vacuum Distribution
  • Fig. 22: Identifying Air Fuel Ratio (A/F) Sensor
  • Fig. 23: Cross Sectional View Of Camshaft Position (CMP) Sensor B
  • Fig. 24: Cross Sectional View Of Crankshaft Position (CKP) Sensor
  • Fig. 25: Cross Sectional View Of Engine Coolant Temperature (ECT) Sensor
  • Fig. 26: Cross Sectional View Of Intake Air Temperature (IAT) Sensor
  • Fig. 27: Cross Sectional View Of Knock Sensor
  • Fig. 28: Cross Sectional View Of Manifold Absolute Pressure (MAP) Sensor
  • Fig. 29: Cross Sectional View Of Output Shaft (Countershaft) Speed Sensor
  • Fig. 30: Identifying Secondary Heated Oxygen Sensor (Secondary HO2S)
  • Fig. 31: Identifying Accelerator Pedal Position (APP) Sensor
  • Fig. 32: Identifying Throttle Body
  • Fig. 33: VTEC/VTC Graph
  • Fig. 34: VTC System Chart
  • Fig. 35: VTEC System Chart
  • Fig. 36: VTEC/VTC System Diagram
  • Fig. 37: Cross Sectional View Of Camshaft Position (CMP) Sensor A
  • Fig. 38: Identifying Intake Air Bypass Control Thermal Valve
  • Fig. 39: Identifying Three Way Catalytic Converter (TWC)
  • Fig. 40: Identifying Positive Crankcase Ventilation (PCV) System
  • Fig. 41: Cross Sectional View Of Fuel Tank Pressure (FTP) Sensor
  • Fig. 42: Cross Sectional View Of EVAP Canister Vent Shut Valve
  • Fig. 43: Identifying Fuel Cap Warning Message ('06-08 Models)
  • Fig. 44: Electronic Throttle Control System Diagram
  • Fig. 45: Evaporative Emission (EVAP) Control Diagram
  • Fig. 46: ECM/PCM Circuit Diagram (1 Of 12)
  • Fig. 47: ECM/PCM Circuit Diagram (2 Of 12)
  • Fig. 48: ECM/PCM Circuit Diagram (3 Of 12)
  • Fig. 49: ECM/PCM Circuit Diagram (4 Of 12)
  • Fig. 50: ECM/PCM Circuit Diagram (5 Of 12)
  • Fig. 51: ECM/PCM Circuit Diagram (6 Of 12)
  • Fig. 52: ECM/PCM Circuit Diagram (7 Of 12)
  • Fig. 53: ECM/PCM Circuit Diagram (8 Of 12)
  • Fig. 54: ECM/PCM Circuit Diagram (9 Of 12)
  • Fig. 55: ECM/PCM Circuit Diagram (10 Of 12)
  • Fig. 56: ECM/PCM Circuit Diagram (11 Of 12)
  • Fig. 57: ECM/PCM Circuit Diagram (12 Of 12)
• TABLES
  • DTC TROUBLESHOOTING INDEX
  • SYMPTOM TROUBLESHOOTING INDEX
  • TERMINAL DESCRIPTION (CONNECTOR A)
  • TERMINAL DESCRIPTION (CONNECTOR B)
  • TERMINAL DESCRIPTION (CONNECTOR C)
  • TERMINAL DESCRIPTION (CONNECTOR D)
  • TERMINAL DESCRIPTION (CONNECTOR E)
  • DRIVING CONDITION

2004-08 ENGINE PERFORMANCE

Fuel and Emissions Systems - TSX

Special Tools

Fig. 1: Identifying Special Tools - Fuel And Emissions Systems
Courtesy of AMERICAN HONDA MOTOR CO., INC.

General Troubleshooting Information

Intermittent Failures

The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the malfunction indicator lamp (MIL) on the dash does not come on, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting. If the MIL was on but then went out, the original problem may be intermittent.

Service information

Some DTCs or symptoms can be caused by a combination of ECM/PCM software and specific driving habits. Periodically, new ECM/PCM software or new service procedures may become available. Always check online for the latest software or service information related to the DTCs or symptoms you are troubleshooting.

Opens and Shorts

"Open" and "Short" are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't work at all. With complex electronics (such as ECMs and PCMs) this can sometimes mean something works, but not the way it's supposed to.

How to Use the HDS (Honda Diagnostic System)

If the MIL (malfunction indicator lamp) has come on

1. Start the engine and check the MIL (A).

   NOTE:

   If the ignition switch is turned ON (II), and the engine is not started, the MIL will stay on for 15-20 seconds (see MALFUNCTION INDICATOR LAMP (MIL) INDICATION (IN RELATION TO READINESS CODES) ).

   Fig. 2: Identifying Malfunction Indicator Lamp
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

2. If the MIL stays on, connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

   Fig. 3: Locating Data Link Connector
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

3. Turn the ignition switch ON (II).
4. Make sure the HDS communicates with the ECM/PCM, and other vehicle systems. If it doesn't, go to '04-06 models DLC CIRCUIT TROUBLESHOOTING , '07-08 models '07-08 MODELS .
5. Check the diagnostic trouble code (DTC) and note it. Also check the freeze data and/or on-board snapshot data, and download any data found. Then refer to the indicated DTCs troubleshooting, and begin the appropriate troubleshooting procedure.

   NOTE:

   Freeze data indicates the engine conditions when the first malfunction, misfire, or fuel trim malfunction was detected. The HDS can read the DTC, freeze data, on-board snapshot, current data, and other engine control module (ECM)/powertrain control module (PCM) data. For specific operations, refer to the user's manual that came with the HDS.

6. If no DTCs are found, go to MIL CIRCUIT TROUBLESHOOTING .

   If the MIL did not stay on

   If the MIL did not stay on but there is a driveability problem, do the symptom troubleshooting.

   If you can't duplicate the DTC

   Some of the troubleshooting requires you to reset the ECM/PCM and try to duplicate the DTC. If the problem is intermittent and you can't duplicate the code, do not continue through the procedure. To do so will only result in confusion and possibly, a needlessly replaced ECM/PCM.

HDS Clear Command

The ECM/PCM stores various specific data to correct the system even if there is no electrical power such as when the battery negative terminal or No. 8 Fl ECU (ECM/PCM) (15 A) fuse are disconnected. Stored data based on failed parts should be cleared by using the "CLEAR COMMAND" of the HDS, if parts are replaced.

The HDS has three kinds of clear commands to meet this purpose. They are DTC clear, ECM/PCM reset, and crank (CKP) pattern clear. DTC clear command erases all stored DTC codes, freeze data, readiness codes, and on-board snapshot. This must be done with the HDS after reproducing the DTC during troubleshooting. The ECM/PCM reset command erases all stored DTC codes, freeze data, readiness codes, on-board snapshot, and all specific data to correct the system except crank (CKP) pattern. If the crank (CKP) pattern data in the ECM/PCM was cleared, you must do the crank (CKP) pattern learn procedure. The crank (CKP) pattern clear command erases only CKP pattern data. This command is for repair of a misfire or the CKP sensor.

Scan Tool Clear Command

If you are using a generic scan tool to clear commands, be aware that there is only one setting for clearing the ECM/PCM, and it clears all commands at the same time (crank (CKP) pattern learn, idle learn, readiness codes, freeze data, on-board snapshot, and DTCs). After you clear all commands, you then need to do these procedures, in this order: ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ); crank (CKP) pattern learn procedure; Test-drive to set readiness codes to complete (see CATALYTIC CONVERTER MONITOR AND READINESS CODE ).

DTC Clear

1. Clear the DTC with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the DLC.

ECM/PCM Reset

This command clears stored specific data from each vehicle such as DTCs, freeze data, on-board snapshot and readiness codes. It does not clear crank (CKP) Pattern data.

1. Reset the ECM/PCM with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the DLC.
5. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).

Crank (CKP) Pattern Clear/Crank (CKP) Pattern Learn

Clear/Learn Procedure (with the HDS)

1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

   Fig. 4: Locating Data Link Connector
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

2. Turn the ignition switch ON (II).
3. Make sure the HDS communicates with the ECM/PCM, and other vehicle systems. If it doesn't, go to '04-06 modelsDLC CIRCUIT TROUBLESHOOTING , '07-08 models '07-08 MODELS .
4. Select CRANK PATTERN in the ADJUSTMENT MENU with the HDS.
5. Select CRANK PATTERN LEARNING with the HDS, and follow the screen prompts.

Learn Procedure (without the HDS)

1. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on.
2. Test-drive the vehicle on a level road: Decelerate (with the throttle fully closed) from an engine speed of 2,500 rpm down to 1,000 rpm with the A/T in 2 position, or M/T in 1st gear.
3. Repeat step 2 above several times.
4. Turn the ignition switch OFF.
5. Turn the ignition switch ON (II), and wait 30 seconds. The crank (CKP) pattern learn procedure is complete.

How to End a Troubleshooting Session (required after any troubleshooting)

1. Reset the ECM/PCM with the HDS.
2. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
3. Turn the ignition switch OFF.
4. Disconnect the HDS from the DLC.

   NOTE:

   The ECM/PCM is part of the immobilizer system. If you replace the ECM/PCM, it will have a different immobilizer code. In order for the engine to start, you must rewrite the immobilizer code with the HDS.

How to Troubleshoot Circuits at the ECM/PCM Connectors

Special Tools Required

• Digital multimeter KS-AHM-32-003 (1) or a commercially available digital multimeter
• Backprobe set 07SAZ-001000A (2)

1. Connect the backprobe adapters (A) to the stacking patch cords (B), and connect the cords to a digital multimeter (C).

   Fig. 5: Connecting Backprobe Adapters To Stacking Patch Cords And Connect Cords To Digital Multimeter
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

2. Using the wire insulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire side until it touches the end of the wire terminal.
3. If you cannot get to the wire side of the connector or the wire side is sealed (A), disconnect the connector and probe the terminals (B) from the terminal side. Do not force the probe into the connector.

   NOTE:

   Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.

   Fig. 6: Disconnecting Connector And Probe Terminals From Terminal Side
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

Updating the ECM/PCM

Special Tools Required

• Honda diagnostic system (HDS) tablet tester
• Honda interface module (HIM) and an iN workstation with HDS and CM update software
• HDS pocket tester
• GNA-600 and an iN workstation with HDS and CM update software

NOTE:

Use this procedure when you need to update the ECM/PCM during a troubleshooting procedure. Make sure the HDS/HIM has the latest software version downloaded from the iN (interactive network). Before you update the ECM/PCM, make sure the battery in the vehicle is fully charged, and connect a jumper battery (not a battery charger) to maintain system voltage. Never turn the ignition switch OFF during the update. If there is a problem with the update, leave the ignition switch ON. To prevent ECM/PCM damage, do not operate anything electrical (headlights, audio system, brakes, A/C, power windows, moonroof (if equipped), door locks, etc.) during the update. To ensure the latest program is installed, do an ECM/PCM update whenever the ECM/PCM is substituted or replaced. You cannot update an ECM/PCM with a program it already has. It will only accept a new program. If you need to diagnose the Honda interface module (HIM) because the HIM's red (# 3) light came on or was flashed during the update, leave the ignition switch in the ON (11) position when you disconnect the HIM from the data link connector (DLC). This will prevent ECM/PCM damage.

1. Turn the ignition switch ON (II), but do not start the engine.
2. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

   Fig. 7: Locating Data Link Connector
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

3. Make sure the HDS communicates with the ECM/PCM, and other vehicle systems. If it doesn't, go to '04-06 modelsDLC CIRCUIT TROUBLESHOOTING , '07-08 models '07-08 MODELS . If you are returning from the DLC circuit troubleshooting, skip steps 4 to 5 and clean the throttle body after updating the ECM/PCM (see THROTTLE BODY CLEANING ).
4. Select the INSPECTION MENU with the HDS.
5. Select the ETCS TEST, then select the TP POSITION CHECK, and follow the HDS screen prompts.

   NOTE:

   If the TP POSITION CHECK indicates FAILED, continue this procedure.

6. Exit the HDS, then select the update program, and follow the screen prompts to update the ECM/PCM.
7. If the software in the ECM/PCM is the latest, disconnect the HDS/HIM from the DLC, and go back to the procedure that you were doing. If the software in the ECM/PCM is not the latest, follow the instructions on the screen. If prompted to choose the PGM-FI system or the A/T system, make sure you update both.

   NOTE:

   If the ECM/PCM update system requires you to cool the ECM/PCM, follow the instructions on screen. If you run into a problem during the update procedure, (programming takes over 15 minutes, status bar goes over 100 %, D or immobilizer light flashes, HDS tablet freezes, etc.), follow these steps to minimize the chance of damaging the ECM/PCM: Leave the ignition switch in the ON (II) position. Connect a jumper battery (do not connect a battery charger). Shut down the HDS. Disconnect the HDS from the DLC. Reboot the HDS. Reconnect the HDS to the DLC, and try the update procedure again.

8. If the TP POSITION CHECK failed in step 5, clean the throttle body (see THROTTLE BODY CLEANING ).
9. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
10. Do the crank (CKP) pattern learn procedure.

Substituting the ECM/PCM

Special Tools Required

• Honda diagnostic system (HDS) tablet tester
• Honda interface module (HIM) and an iN workstation with HDS and CM update software
• HDS pocket tester
• GNA-600 and an iN workstation with HDS and CM update software

NOTE:

Use this procedure when you need to substitute a known-good ECM/PCM during troubleshooting procedures.

1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

   Fig. 8: Locating Data Link Connector
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

2. Turn the ignition switch ON (II).
3. Make sure the HDS communicates with the ECM/PCM. If it doesn't, go to DLC CIRCUIT TROUBLESHOOTING , '07-08 MODELS '07-08 models . If you are returning from DLC circuit troubleshooting, skip step 5 to 10, and clean the throttle body after substituting the ECM/PCM (see THROTTLE BODY CLEANING ).
4. Select the INSPECTION MENU with the HDS.
5. Select the ETCS TEST, then select the TP POSITION CHECK, and follow the screen prompts.

   NOTE:

   If the TP POSITION CHECK indicates FAILED, continue this procedure.

6. Turn the ignition switch OFF.
7. Jump the SCS line with the HDS.
8. Remove the center lower covers (A).

   Fig. 9: Locating Center Lower Covers (with Torque Specifications)
   Courtesy of AMERICAN HONDA MOTOR CO., INC.

9. Remove the duct (B).
10. Disconnect the ECM/PCM connectors (C).
11. Remove the bolts (D), then remove the ECM/PCM (E).
12. Install the parts in the reverse order of removal.
13. Turn the ignition switch ON (II).

    NOTE:

    For '05-08 models: DTC P0630 "VIN Not Programmed or Mismatch" may be stored because the VIN has not been programmed into the ECM/PCM; ignore it, and continue this procedure.

14. Manually input the VIN to the ECM/PCM with the HDS.
15. Update the ECM/PCM if it does not have the latest software.
16. Select the IMMOBI SYSTEM with the HDS.
17. Enter the immobilizer code using the ECM/PCM replacement procedure in the HDS; this allows you to start the engine.
18. Reset the ECM/PCM with the HDS.
19. If the TP POSITION CHECK failed in step 5, clean the throttle body (see THROTTLE BODY CLEANING ).
20. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
21. Do the crank (CKP) pattern learn procedure.

OBD Status

The OBD status shows the current system status of each DTC and all of the parameters. This function is used to see if the repair was successfully completed. The results of diagnostic tests for the DTC are displayed as:

• PASSED: The on board diagnosis is successfully finished.
• FAILED: The on board diagnosis has finished but failed.
• EXECUTING: The vehicle is in enable criteria conditions for the DTC and the on board diagnosis is running.
• NOT COMPLETED: The on board diagnosis was running but is out of the enable conditions of the DTC.
• OUT OF CONDITION: The vehicle has stayed out of the enable conditions for the DTC.

DTC Troubleshooting Index

DTC TROUBLESHOOTING INDEX

DTC (MIL indication (2))	Two Drive Cycle Detection	Detection Item	MIL
P0010 (56)	-	Variable Valve Timing Control (VTC) Oil Control Solenoid Valve Malfunction	ON
P0011 (56)	o	Variable Valve Timing Control (VTC) System Malfunction	ON
P0107 (3)	-	Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage	ON
P0108 (3)	-	Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage	ON
P0111 (10) (7)	o	Intake Air Temperature (IAT) Sensor Circuit Range/Performance Problem	ON
P0112 (10)	-	Intake Air Temperature (IAT) Sensor Circuit Low Voltage	ON
P0113 (10)	-	Intake Air Temperature (IAT) Sensor Circuit High Voltage	ON
P0116 (86) (8)	o	Engine Coolant Temperature (ECT) Sensor Circuit Range/ Performance Problem	ON
P0116 (86) (8)	o	Engine Coolant Temperature (ECT) Sensor 1 Circuit Range/ Performance Problem	ON
P0117 (6) (8)	-	Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage	ON
P0117 (6) (7)	-	Engine Coolant Temperature (ECT) Sensor 1 Circuit Low Voltage	ON
P0118 (6) (7)	-	Engine Coolant Temperature (ECT) Sensor Circuit High Voltage	ON
P0118 (6) (7)	-	Engine Coolant Temperature (ECT) Sensor 1 Circuit High Voltage	ON
P0122 (7)	-	Throttle Position (TP) Sensor A Circuit Low Voltage	ON
P0123 (7)	-	Throttle Position (TP) Sensor A Circuit High Voltage	ON
P0125 (86) (8)	o	Engine Coolant Temperature (ECT) Sensor Malfunction/Slow Response	ON
P0125 (86) (7)	o	Engine Coolant Temperature (ECT) Sensor 1 Malfunction/Slow Response	ON
P0128 (87) (8)	o	Cooling System Malfunction	ON
P0128 (87) (7)	o	Cooling System Malfunction	ON
P0133 (61) (8)	o	Air Fuel Ratio (A/F) Sensor (Sensor 1) Malfunction/Slow Response	ON
P0133 (61) (7)	o	Air Fuel Ratio (A/F) Sensor (Sensor 1) Malfunction/Slow Response	ON
P0134 (41)	-(8) o (7)	Air Fuel Ratio (A/F) Sensor (Sensor 1) Heater System Malfunction	ON
P0135 (41)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) Heater Circuit Malfunction	ON
P0137 (63) (5)	o	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit Low Voltage	ON
P0137 (63) (6)	-	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit Low Voltage	ON
P0138 (63) (5)	-	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit High Voltage	ON
P0138 (63) (6)	-	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit High Voltage	ON
P0139 (63) (5)	o	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Slow Response	ON
P0139 (63) (6)	o	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Slow Response	ON
P0141 (65)	-	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Heater Circuit Malfunction	ON
P0171 (45)	o	Fuel System Too Lean	ON
P0172 (45)	o	Fuel System Too Rich	ON
P0222 (7)	-	Throttle Position (TP) Sensor B Circuit Low Voltage	ON
P0223 (7)	-	Throttle Position (TP) Sensor B Circuit High Voltage	ON
P0300 (75) any combination of the following P0301 (71) P0302 (72) P0303 (73) P0304 (74)	o	Random Misfire Detected	ON
P0301 (71)	o	No. 1 Cylinder Misfire Detected	ON
P0302 (72)	o	No. 2 Cylinder Misfire Detected	ON
P0303 (73)	o	No. 3 Cylinder Misfire Detected	ON
P0304 (74)	o	No. 4 Cylinder Misfire Detected	ON
P0325 (23)	-	Knock Sensor Circuit Malfunction	ON
P0335 (4)	-	Crankshaft Position (CKP) Sensor No Signal	ON
P0339 (4)	-	Crankshaft Position (CKP) Sensor Circuit Intermittent Interruption	ON
P0340 (57)	-	Camshaft Position (CMP) Sensor A No Signal	ON
P0341 (57)	-	Camshaft Position (CMP) Sensor A and Crankshaft Position (CKP) Sensor Incorrect Phase Detected	ON
P0344 (57)	-	Camshaft Position (CMP) Sensor A Circuit Intermittent Interruption	ON
P0365 (8)	-	Camshaft Position (CMP) Sensor B No Signal	ON
P0369 (8)	-	Camshaft Position (CMP) Sensor B Circuit Intermittent Interruption	ON
P0420 (67) (5)	o	Catalyst System Efficiency Below Threshold	ON
P0420 (67) (6)	o	Catalyst System Efficiency Below Threshold	ON
P0442 (90) (8)	o	Evaporative Emission (EVAP) System Small Leak Detected	ON
P0443 (92)	-	Evaporative Emission (EVAP) Canister Purge Valve Circuit Malfunction	ON
P0451 (91)	o	Fuel Tank Pressure (FTP) Sensor Circuit Range/Performance Problem	ON
P0452 (91)	-	Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage	ON
P0453 (91)	-	Fuel Tank Pressure (FTP) Sensor Circuit High Voltage	ON
P0455 (90) (7)	o	Evaporative Emission (EVAP) System Large Leak Detected	ON
P0456 (90)	o	Evaporative Emission (EVAP) System Very Small Leak Detected	ON
P0457 (90)	o	Evaporative Emission (EVAP) System Leak Detected/Fuel Fill Cap Loose or Missing	ON
P0461 (121) (7)	-	Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit Range/ Performance Problem	OFF
P0462 (121) (7)	-	Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit Low Voltage	OFF
P0463 (121) (7)	-	Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit High Voltage	OFF
P0496 (92)	o	Evaporative Emission (EVAP) System High Purge Flow Detected	ON
P0497 (90)	o	Evaporative Emission (EVAP) System Low Purge Flow Detected	ON
P0498 (117)	-	Evaporative Emission (EVAP) Canister Vent Shut Valve Circuit Low Voltage	ON
P0499 (117)	-	Evaporative Emission (EVAP) Canister Vent Shut Valve Circuit High Voltage	ON
P0506 (14)	o	Idle Control System RPM Lower Than Expected	ON
P0507 (14)	o	Idle Control System RPM Higher Than Expected	ON
P0562 (34) (7)	-	Charging System Low Voltage	OFF
P0563 (34)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Power Source Circuit Unexpected Voltage	OFF
P0602 (196) (7)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Programming Error	ON
P0603 (131) (9)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Internal Control Module Keep Alive Memory (KAM) Error	ON
P0606 (0)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Processor Malfunction	ON
P062F (131) (11)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Internal Control Module Keep Alive Memory (KAM) Error	ON
P0630 (139) (6)	-	VIN Not Programmed or Mismatch	ON
P0685 (135)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Power Control Circuit/Internal Circuit Malfunction	ON
P0700 (70) (1), (3)	-	Automatic Transaxle Control System Malfunction	ON
P0700 (70) (3)	-	Automatic Transaxle Control System Malfunction	OFF
P0720 (122) (4)	-	Output shaft (Countershaft) Speed Sensor Circuit Malfunction	ON
P1009 (56) (6)	-	Variable Valve Timing Control (VTC) Advance Malfunction	ON
P1109 (13) (6)	-	Barometric Pressure (BARO) Sensor Circuit Out of Range High	ON
P1116 (86) (7)	o	Engine Coolant Temperature (ECT) Sensor 1 Circuit Range/ Performance Problem	ON
P1128 (5)	o	Manifold Absolute Pressure (MAP) Sensor Signal Lower Than Expected	ON
P1129 (5)	o	Manifold Absolute Pressure (MAP) Sensor Signal Higher Than Expected	ON
P1157 (48)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) AFS Circuit High Voltage	ON
P1172 (61) (7)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) Circuit Out of Range High	ON
P1297 (20)	-	Electrical Load Detector (ELD) Circuit Low Voltage	OFF
P1298 (20)	-	Electrical Load Detector (ELD) Circuit High Voltage	OFF
P1454 (91)	o	Fuel Tank Pressure (FTP) Sensor Range/Performance Problem	ON
P1549 (34) (7)	-	Charging System High Voltage	OFF
P1683 (40)	-	Throttle Valve Default Position Spring Performance Problem	ON
P1684 (40)	-	Throttle Valve Return Spring Performance Problem	ON
P16BB (116) (7)	-	Alternator B Terminal Circuit Low Voltage	OFF
P16BC (116) (7)	-	Alternator FR Terminal Circuit/IGP Circuit Low Voltage	OFF
P2101 (40)	-	Throttle Actuator System Malfunction	ON
P2108 (40)	-	Throttle Actuator Control Module Problem	ON
P2118 (40)	-	Throttle Actuator Current Range/Performance Problem	ON
P2122 (37)	-	Accelerator Pedal Position (APP) Sensor A (Throttle Position (TP) Sensor D) Circuit Low Voltage	ON
P2123 (37)	-	Accelerator Pedal Position (APP) Sensor A (Throttle Position (TP) Sensor D) Circuit High Voltage	ON
P2127 (37)	-	Accelerator Pedal Position (APP) Sensor B (Throttle Position (TP) Sensor E) Circuit Low Voltage	ON
P2128 (37)	-	Accelerator Pedal Position (APP) Sensor B (Throttle Position (TP) Sensor E) Circuit High Voltage	ON
P2135 (7)	-	Throttle Position (TP) Sensor A/B Incorrect Voltage Correlation	ON
P2138 (37)	-	Accelerator Pedal Position (APP) Sensor A/B (Throttle Position (TP) Sensor D/E) Incorrect Voltage Correlation	ON
P2176 (40)	-	Throttle Actuator Control System Idle Position Not Learned	ON
P2183 (192) (7)	o	Engine Coolant Temperature (ECT) Sensor 2 Circuit Range/ Performance Problem	ON
P2184 (192) (9)	-	Engine Coolant Temperature (ECT) Sensor 2 Circuit Low Voltage	ON
P2185 (192) (7)	-	Engine Coolant Temperature (ECT) Sensor 2 Circuit High Voltage	ON
P2195 (48)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) Signal Stuck Lean	ON
P2227 (13)	o	Barometric Pressure (BARO) Sensor Circuit Range/Performance Problem	ON
P2228 (13)	-	Barometric Pressure (BARO) Sensor Circuit Low Voltage	ON
P2229 (13)	-	Barometric Pressure (BARO) Sensor Circuit High Voltage	ON
P2238 (48)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) AFS+ Circuit Low Voltage	ON
P2252 (48)	-	Air Fuel Ratio (A/F) Sensor (Sensor 1) AFS - Circuit Low Voltage	ON
P2270 (63)(6)	o	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit Signal Stuck Lean	ON
P2271 (63)(6)	o	Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit Signal Stuck Rich	ON
P2279 (109)	o	Intake Air System Leak Detected	ON
P2422 (117)	o	Evaporative Emission (EVAP) Canister Vent Shut Valve Stuck Closed Malfunction	ON
P2552 (40)	-	Throttle Actuator Control Module Relay Malfunction	ON
P2610 (132)(7)	-	Engine Control Module (ECM)/Powertrain Control Module (PCM) Ignition Off Internal Timer Malfunction	ON
P2646 (22)	-	Rocker Arm Oil Pressure Switch (VTEC Oil Pressure Switch) Circuit Low Voltage	ON
P2647 (22)	-	Rocker Arm Oil Pressure Switch (VTEC Oil Pressure Switch) Circuit High Voltage	ON
P2648 (21)	-	Rocker Arm Oil Control Solenoid (VTEC Solenoid Valve) Circuit Low Voltage	ON
P2649 (21)	-	Rocker Arm Oil Control Solenoid (VTEC Solenoid Valve) Circuit High Voltage	ON
P2A00 (61)	o	Air Fuel Ratio (A/F) Sensor (Sensor 1) Circuit Range/Performance Problem	ON
U0073 (126) (9)	-	F-CAN Malfunction (BUS-OFF)	OFF(8)/ON(10)
U0073 (126) (11)	-	F-CAN Malfunction (BUS-OFF)	ON
U0107 (30)	-	Lost Communication With Throttle Actuator Control Module	ON
U0122 (126)	-	F-CAN Malfunction (Engine Control Module (ECM)/Powertrain Control Module (PCM)-VSA Modulator-Control Unit)	OFF
U0155 (126) (9)	-	F-CAN Malfunction (Engine Control Module (ECM)/Powertrain Control Module (PCM)-Gauge Control Module)	OFF(8)/ON(10)
U0155 (126) (11)	-	F-CAN Malfunction (Engine Control Module (ECM)/Powertrain Control Module (PCM)-Gauge Control Module)	ON
NOTE: The above DTCs are indicated when the PGM-FI system is selected in the HDS. Some automatic transmission DTCs cause the MIL to come on. If the MIL is on and no DTCs are indicated in the PGM-FI system, selected the A/T system, and check for automatic transmission DTCs. (1) The D indicator and MIL may come on at the same time. (2) These DTCs are indicated by a blinking MIL when the SCS line is jumped with the HDS. (3) A/T (4) M/T (5) '04 model (6) '05-08 models (7) '06-08 models (8) '04-05 models (9) '04-05 models (10) '06 model (11) '07-08 models

Symptom Troubleshooting Index

When the vehicle has one of these symptoms, check for a diagnostic trouble code (DTC) with the HDS. If there is no DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.

SYMPTOM TROUBLESHOOTING INDEX

Symptom	Diagnostic procedure	Also check for
Engine will not start (MIL works OK, no DTCs set)	Test the battery (see BATTERY TEST ). Test the starter (see STARTER PERFORMANCE TEST ). Check the fuel pressure (see FUEL PRESSURE TEST ). Troubleshoot the fuel pump circuit (see FUEL PUMP CIRCUIT TROUBLESHOOTING ).	Low compression No ignition spark Intake air leaks Locked up engine Broken cam chain Contaminated fuel
Engine will not start (MIL comes on and stays on, or never comes on at all, no DTCs set)	'04-06 models: Troubleshoot the MIL circuit (see MIL CIRCUIT TROUBLESHOOTING ). '07-08 models: Troubleshoot the DLC circuit (see '07-08 MODELS ).
Engine will not start (immobilizer indicator stays on or flashes) ('04-06 models)	Troubleshoot the immobilizer system (see TROUBLESHOOTING ).
Engine starts but stalls immediately (MIL works OK, no DTCs set, immobilizer indicator stays on or flashes) ('07-08 models)	Troubleshoot the immobilizer system (see '07-08 MODELS ).
Engine is hard to start (MIL works OK, no DTCs set)	Test the battery (see BATTERY TEST ). Check the fuel pressure (see FUEL PRESSURE TEST ). Clean the throttle body (see THROTTLE BODY CLEANING ).	Low compression Intake air leaks Contaminated fuel Weak spark
Cold fast idle too low (MIL works OK, no DTCs set)	Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ). Check the idle speed (see IDLE SPEED INSPECTION ). Clean the throttle body (see THROTTLE BODY CLEANING ).
Cold fast idle too high (MIL works OK, no DTCs set)	Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ). Check the idle speed (see IDLE SPEED INSPECTION ). Inspect/adjust the throttle cable (see THROTTLE CABLE ADJUSTMENT ). Do the throttle position learning check (see THROTTLE POSITION LEARNING CHECK ).
Idle speed fluctuates (MIL works OK, no DTCs set)	Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ). Check the idle speed (see IDLE SPEED INSPECTION ). Inspect/adjust the throttle cable (see THROTTLE CABLE ADJUSTMENT ). Do the carbon accumulation check (see THROTTLE BODY TEST ). Troubleshoot the A/C signal circuit (see A/C SIGNAL CIRCUIT TROUBLESHOOTING ).	Intake vacuum leaks
After warming up, idle speed is below specification without load (MIL works OK, no DTCs set)	Troubleshoot the alternator FR signal circuit; '04 model (see ALTERNATOR FR SIGNAL CIRCUIT TROUBLESHOOTING ). '05-08 models (see '05-08 MODELS ). Do the carbon accumulation check (see THROTTLE BODY TEST ).
After warming up, idle speed is above specification without load (MIL works OK, no DTCs set)	Troubleshoot the alternator FR signal circuit; '04 model (see ALTERNATOR FR SIGNAL CIRCUIT TROUBLESHOOTING ). '05-08 models (see '05-08 MODELS ). Inspect the APP sensor (see APP SENSOR SIGNAL INSPECTION ).
After warming up, idle speed drops when steering wheel is turning (MIL works OK, no DTCs set)	Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ). Troubleshoot the PSP switch circuit (see PSP SWITCH SIGNAL CIRCUIT TROUBLESHOOTING ). Do the carbon accumulation check (see THROTTLE BODY TEST ).	Power steering system problems
Low power (MIL works OK, no DTCs set)	Check the fuel pressure (see FUEL PRESSURE TEST ). Inspect/adjust the throttle cable (see THROTTLE CABLE ADJUSTMENT ).	Low compression Incorrect camshaft timing Incorrect engine oil level
Engine stalls (MIL works OK, no DTCs set)	Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ). Check the fuel pressure (see FUEL PRESSURE TEST ). Check the idle speed (see IDLE SPEED INSPECTION ). Troubleshoot the brake pedal position switch signal circuit (see BRAKE PEDAL POSITION SWITCH SIGNAL CIRCUIT TROUBLESHOOTING ).	Intake air leaks Faulty harness and sensor connections
Difficult to refuel (MIL works OK, no DTCs set)	Check the fuel vent tube between the EVAP canister and the fuel tank. Check the fuel tank vapor recirculation tube between the fuel pipe and the fuel tank. Replace the fuel tank (see FUEL TANK REPLACEMENT ).	Malfunctioning gas station filling nozzle.
Fuel overflows during refueling (No DTCs set)	Replace the fuel tank (see FUEL TANK REPLACEMENT ).	Malfunctioning gas station filling nozzle.
HDS does not communicate with the ECM/PCM or the vehicle ('07-08 models)	Troubleshoot the DLC circuit (see '07-08 MODELS ).

System Description

Electronic Control System

The functions of the fuel and emission control systems are managed by the engine control module (ECM) on vehicles with manual transmissions or the powertrain control module (PCM) on vehicles with automatic transmissions.

Self-Diagnosis

The ECM/PCM detects a failure of a signal from a sensor or another control unit and stores a Temporary DTC or a DTC. Depending on the failure, a DTC is stored in either the first or the second drive cycle. When a DTC is stored, the ECM/PCM turns on the malfunction indicator lamp (MIL) by a signal sent to the gauge via F-CAN.

• One Drive Cycle Detection Method

  When an abnormality occurs in the signal from a sensor or another control unit, the ECM/PCM stores a DTC for the failure and turns on the MIL immediately.

• Two Drive Cycle Detection Method

  When an abnormality occurs in the signal from a sensor or another control unit in the first drive cycle, the ECM/PCM stores a Temporary DTC. If the failure continues in the second drive cycle, the ECM/PCM stores a DTC and turns on the MIL.

Fail-safe Function

When an abnormality occurs in the signal from a sensor or another control unit, the ECM/PCM ignores that signal and substitutes a pre-programmed value for them that allows the engine to continue running. This causes a DTC to be stored and the MIL to come on.

MIL Bulb Check and Readiness Code Condition

When the ignition switch is turned ON (II), the ECM/PCM turns on the MIL via the F-CAN circuit for about 15 to 20 seconds to check the bulb condition. If any readiness codes are not set to complete, the MIL flashes five times. If all readiness codes are set to complete, the MIL goes off.

Self Shut Down (SSD) Mode

After the ignition switch is turned OFF, the ECM/PCM stays on (up to 15 minutes). If the ECM/PCM connector is disconnected during this time, the ECM/PCM may be damaged. To cancel this mode, disconnect the negative cable from the battery or jump the SCS line with the HDS after the ignition switch is turned OFF.

ECM/PCM Electrical Connections

Fig. 10: ECM/PCM Electrical Connections Diagram (1 Of 5)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 11: ECM/PCM Electrical Connections Diagram (2 Of 5)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 12: ECM/PCM Electrical Connections Diagram (3 Of 5)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 13: ECM/PCM Electrical Connections Diagram (4 Of 5)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 14: ECM/PCM Electrical Connections Diagram (5 Of 5)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

ECM/PCM Inputs and Outputs at Connector A (31P)

Fig. 15: Identifying ECM/PCM Inputs And Outputs At Connector A (31P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

Standard battery voltage is about 12 V.

TERMINAL DESCRIPTION (CONNECTOR A)

Terminal number	Wire color	Terminal name	Description	Signal
1	RED/BLU	KS (KNOCK SENSOR)	Detects knock sensor signal	With engine knocking: pulses
2	YEL/BLK	IGP2 (POWER SOURCE)	Power source for ECM/PCM circuit	With ignition switch ON (II): battery voltage With ignition switch OFF: about 0 V
3	YEL/BLK	IGP1 (POWER SOURCE)	Power source for ECM/PCM circuit	With ignition switch ON (II): battery voltage With ignition switch OFF: about 0 V
4	BLK	PG2 (POWER GROUND)	Ground circuit for ECM/PCM	Less than 1.0 V at all times
5	BLK	PG1 (POWER GROUND)	Ground circuit for ECM/PCM	Less than 1.0 V at all times
6	GRN	CMPB (CAMSHAFT POSITION SENSOR B)	Detects CMP sensor B signal	With engine running: pulses
7	BLU	CKP (CRANKSHAFT POSITION SENSOR)	Detects CKP sensor signal	With engine running: pulses
8	BRN/YEL	LG2 (LOGIC GROUND)	Ground circuit for ECM/PCM	Less than 1.0 Vat all times
9	BRN/YEL	LG1 (LOGIC GROUND)	Ground circuit for ECM/PCM	Less than 1.0 Vat all times
10	GRN	AFSHTC (AIR FUEL RATIO (A/F) SENSOR HEATER CONTROL)	Drives A/F sensor heater	With ignition switch ON (II): battery voltage With fully warmed up engine running: about 0 V
13	BRN	IGPLS4 (No. 4 IGNITION COIL PULSE)	Drives No. 4 ignition coil	With ignition switch ON (II): about 0 V With engine running: pulses
14	WHT/BLU	IGPLS3 (No. 3 IGNITION COIL PULSE)	Drives No. 3 ignition coil
15	BLU/RED	IGPLS2 (No. 2 IGNITION COIL PULSE)	Drives No. 2 ignition coil
16	YEL/GRN	IGPLS1 (No. 1 IGNITION COIL PULSE)	Drives No. 1 ignition coil
18	BLK/BLU	NC (OUTPUT SHAFT (COUNTERSHAFT) SPEED SENSOR)	Detects output shaft (countershaft) speed sensor signal	With ignition switch ON (II): about 0 V or about 5.0 V While driving: about 2.5 V
19	BLU/WHT	CMPA (CAMSHAFT POSITION SENSOR A)	Detects CMP sensor A signal	With engine running: pulses
20	YEL/BLU	VCC2 (SENSOR VOLTAGE)	Provides sensor voltage	With ignition switch ON (II): about 5.0 V With ignition switch OFF: about 0 V
21	YEL/RED	VCC1 (SENSOR VOLTAGE)	Provides sensor voltage	With ignition switch ON (II): about 5.0 V With ignition switch OFF: about 0 V
23	GRN/YEL	SG2 (SENSOR GROUND)	Sensor ground	Less than 1.0 Vat all times
24	GRN/WHT	SG1 (SENSOR GROUND)	Sensor ground	Less than 1.0 V at all times
25	RED/YEL	APSB (ACCELERATOR PEDAL POSITION (APP) SENSOR B)	Detects APP sensor B signal	With ignition switch ON (II) and accelerator pedal pressed: about 2.3 V With ignition switch ON (II) and accelerator pedal released: about 0.2 V
26	RED/BLU	APSA (ACCELERATOR PEDAL POSITION (APP) SENSOR A)	Detects APP sensor A signal	With ignition switch ON (II) and accelerator pedal pressed: about 4.5 V With ignition switch ON (II) and accelerator pedal released: about 0.5 V
28	RED/YEL	AFS- (AIR FUEL RATIO (A/F) SENSOR, SENSOR 1 -SIDE)	Detects A/F sensor (sensor 1) signal
30	GRN/RED	MAP (MANIFOLD ABSOLUTE PRESSURE SENSOR)	Detects MAP sensor signal	With ignition switch ON (II): about 3.0 V At idle: about 1.0 V (depending on engine speed)
31	RED	AFS+ (AIR FUEL RATIO (A/F) SENSOR, SENSOR 1 +SIDE)	Detects A/F sensor (sensor 1) signal

ECM/PCM Inputs and Outputs at Connector B (24P)

Fig. 16: Identifying ECM/PCM Inputs And Outputs At Connector B (24P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

Standard battery voltage is about 12 V.

TERMINAL DESCRIPTION (CONNECTOR B)

Terminal number	Wire color	Terminal name	Description	Signal
1	BLU/WHT	VTC (VTC OIL CONTROL SOLENOID VALVE)	Drives VTC oil control solenoid valve	With ignition switch ON (II): about 0 V
2	YEL	INJ4 (No. 4 INJECTOR)	Drives No. 4 injector	At idle: duty controlled With ignition switch ON (II): battery voltage
3	BLU	INJ3 (No. 3 INJECTOR)	Drives No. 3 injector
4	RED	INJ2 (No. 2 INJECTOR)	Drives No. 2 injector
5	BRN	INJ1 (No. 1 INJECTOR)	Drives No. 1 injector
6	GRN/YEL	VTS (ROCKER ARM OIL CONTROL SOLENOID) (VTEC SOLENOID VALVE))	Drives rocker arm oil control solenoid (VTEC solenoid valve)	At idle: about 0V
8	RED/WHT	ECT (ENGINE COOLANT TEMPERATURE SENSOR (ENGINE COOLANT TEMPERATURE SENSOR 1)'3)	Detects ECT sensor (ECT sensor 1)(1) signal	With ignition switch ON (II): about 0.5-4.8 V (depending on engine coolant temperature) With fully warmed up engine: about 0.5-0.7 V
10	WHT/BLU	ALTL (ALTERNATOR L SIGNAL)	Detects alternator signal	With ignition switch ON (II): about 0 V With engine running: battery voltage
11	BLU/BLK	VTPSW (ROCKER ARM OIL PRESSURE SWITCH) (VTEC OIL PRESSURE SWITCH))	Detects rocker arm oil pressure switch (VTEC oil pressure switch) signal	With engine at low speed: about 0 V With engine at high speed: battery voltage
13	WHT/RED	ALTF (ALTERNATOR FR SIGNAL)	Detects alternator FR signal	With engine running: about 0-5.0 V (depending on electrical load)
15	BLU/YEL	MCS (ENGINE MOUNT CONTROL SOLENOID VALVE)	Drives engine mount control solenoid valve	At idle: about 0 V Above idle: battery voltage With ignition switch ON (II): battery voltage
17	RED/YEL	IAT (INTAKE AIR TEMPERATURE SENSOR)	Detects IAT sensor signal	With ignition switch ON (II): about 0.5-4.8 V (depending on intake air temperature)
18	WHT/GRN	ALTC (ALTERNATOR CONTROL)	Sends alternator control signal	With engine running and fully warmed up: about 8.0 V
19	GRN	SEFD (THROTTLE ACTUATOR CONTROL SERIAL SIGNAL)	Sends throttle actuator control serial signal
20	BLU	SEDF (THROTTLE ACTUATOR CONTROL SERIAL SIGNAL)	Detects throttle actuator control serial signal
21	YEL/BLU	PCS (EVAPORATIVE EMISSION CANISTER PURGE VALVE)	Drives EVAP canister purge valve	With engine running, engine coolant below 131°F (55°C): battery voltage With engine running, engine coolant above 131°F (55°C): duty controlled
(1) '06-08 models

PCM Inputs and Outputs at Connector C (22P)

Fig. 17: Identifying PCM Inputs And Outputs At Connector C (22P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

Standard battery voltage is about 12 V.

TERMINAL DESCRIPTION (CONNECTOR C)

Terminal number	Wire color	Terminal name	Description	Signal
1(1)	RED/BLK	LSA (A/T CLUTCH PRESSURE CONTROL SOLENOID VALVE A)	Drives A/T clutch pressure control solenoid valve A	With ignition switch ON (II): current control
2(1)	GRN	SHC (SHIFT SOLENOID VALVE C)	Drives shift solenoid valve C	With engine running in N, D, D3, and M position (in 1st, 3rd and 5th gears): battery voltage With engine running in P, R position, or D, D3, and M position (in 2nd, 4th gears): about 0 V
3(1)	YEL	SHE (SHIFT SOLENOID VALVE E)	Drives shift solenoid valve E	With engine running in P, R positions: battery voltage With engine running in N, D, D3, and M position (in 1st gear): about 0 V
4(1)	GRN/WHT	SHB (SHIFT SOLENOID VALVE B)	Drives shift solenoid valve B	With engine running in P, R, N, or D, D3, and M position (in 1st, 2nd gears): battery voltage With engine running in D, D3, and M position (in 3rd, 4th, 5th gears): about 0 V
5(1)	GRN/RED	SHD (SHIFT SOLENOID VALVE D)	Drives shift solenoid valve D	With engine running in 2 or D, D3, and M position (in 2nd, 5th gears): battery voltage With engine running in P, R, N, or D, D3, and M position (in 1st, 3rd, 4th gears): about 0 V
6(1)	BLU/BLK	SHA (SHIFT SOLENOID VALVE A)	Drives shift solenoid valve A	With engine running in R, or D, D3, and M position (in 1st, 4th, 5th gears): battery voltage With engine running in P, N and D, D3, and M position (in 2nd, 3rd gears): about 0 V
7(1)	BLU/YEL	LSC (A/T CLUTCH PRESSURE CONTROL SOLENOID VALVE C)	Drives A/T clutch pressure control solenoid valve C	With ignition switch ON (II): current control
9(1)	RED	ATPD3 (TRANSMISSION RANGE SWITCH D3 POSITION)	Detects transmission range switch D3 position signal input	In D3 position: about 0 V In any position other than D3: about 5.0 V
10(1)	BLU/WHT	OP3SW (3RD CLUTCH TRANSMISSION FLUID PRESSURE SWITCH)	Detects 3rd clutch transmission fluid pressure switch signal output	With ignition switch ON (II): about 5.0 V With 3rd clutch pressure: about 0 V
11(1)	BLU/YEL	P-PINSW (PARK PIN SWITCH)	Detects park pin switch signal	With park pin switch ON (II): about 0 V With park pin switch OFF: about 5.0 V
12(1)	RED/WHT	ATPRVS (TRANSMISSION RANGE SWITCH R POSITION)	Detects transmission range switch R position signal input	In R position: about 0 V In any position other than R: about 5.0 V
13(1)	BLU/RED	OP2SW (2ND CLUTCH TRANSMISSION FLUID PRESSURE SWITCH)	Detects 2nd clutch transmission fluid pressure switch signal input	With ignition switch ON (II): about 5.0 V With 2nd clutch pressure: about 0 V
14(1)	RED/YEL	ATFT (ATF TEMPERATURE SENSOR)	Detects ATF temperature sensor signal input	With ignition switch ON (II): about 0.2-3.0 V (depending on ATF temperature)
15(1)	BRN/WHT	LSB (A/T CLUTCH PRESSURE CONTROL SOLENOID VALVE B)	Drives A/T clutch pressure control solenoid valve B	With ignition switch ON (II): current control
17(1)	YEL/GRN	ATPD (TRANSMISSION RANGE SWITCH D POSITION)	Detects transmission range switch D position signal	In D position: about 0 V In any position other than D: about 5.0 V
18(1)	BLU/YEL	ATPFWD (TRANSMISSION RANGE SWITCH D/D3 POSITION)	Detects transmission range switch D, D3 position signal	In D, D3 position: about 0 V In any position other than D, D3: about 5.0 V
19(1)	WHT/RED	NM (INPUT SHAFT (MAINSHAFT) SPEED SENSOR)	Detects input shaft (mainshaft) speed sensor signal	With ignition switch ON (II): about 0 V or about 5.0 V With engine running in N position: about 2.5 V
20(1)	RED/BLK	ATPN (TRANSMISSION RANGE SWITCH N POSITION)	Detects transmission range switch N position signal	In N position: about 0 V In any position other than N: about 5.0 V
(1) A/T

ECM/PCM Inputs and Outputs at Connector D (17P)

Fig. 18: Identifying ECM/PCM Inputs And Outputs At Connector D (17P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

Standard battery voltage is about 12 V.

TERMINAL DESCRIPTION (CONNECTOR D)

Terminal number	Wire color	Terminal name	Description	Signal
2(1)	BRN	SMODE (SEQUENTIAL SPORT SHIFT MODE)	Detects sequential sport shift mode switch signal	In M position: about 0 V In any position other than M: about 5.0 V
3(1)	WHT/BLU (WHT)(3)	SUP (UPSHIFT SWITCH)	Detects upshift switch signal	In M position and shift lever pushed toward upshift position: about 0 V In M position and shift lever in neutral position: about 5.0 V
5(1)	WHT	ATPR (TRANSMISSION RANGE SWITCH R POSITION)	Detects transmission range switch R position signal	In R position: about 0 V In any position other than R: about 5.0 V
6(1)	BLU/BLK (BLU)(3)	ATPP (TRANSMISSION RANGE SWITCH P POSITION)	Detects transmission range switch P position signal	In P position: about 0 V In any position other than P: about 5.0 V
8	BRN	BKSWNC (BRAKE PEDAL POSITION SWITCH)	Detects brake pedal position switch signal	With ignition switch ON (II) and brake pedal released: battery voltage With ignition switch ON (II) and brake pedal pressed: about 0 V
9(1)	ORN	SDN (DOWNSHIFT SWITCH)	Detects downshift switch signal	In M position and shift lever pushed toward downshift position: about 0 V In M position and shift lever in neutral position: about 5.0 V
9(2)	LT BLU	CRMTCLS (CRUISE CLUTCH PEDAL POSITION SIGNAL)	Detects cruise clutch pedal position switch signal	With ignition switch ON (II) and clutch pedal released: battery voltage With ignition switch ON (II) and clutch pedal pressed: about 0 V
10(1)	LTGRN	METINH (METER DISPLAY INHIBIT SIGNAL)	Sends inhibit signal	With ignition switch ON (II): battery voltage
15	BRN	DBWRLY (THROTTLE ACTUATOR CONTROL MODULE RELAY)	Drives throttle actuator control module relay	With ignition switch ON (II): about 0 V
(1) A/T (2) M/T (3) '06-08 models

ECM/PCM Inputs and Outputs at Connector E (31P)

Fig. 19: Identifying ECM/PCM Inputs And Outputs At Connector E (31P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

Standard battery voltage is about 12 V.

TERMINAL DESCRIPTION (CONNECTOR E)

Terminal number	Wire color	Terminal name	Description	Signal
1(3)	BLU	ECT2 (ENGINE COOLANT TEMPERATURE SENSOR 2)	Detects ECT sensor 2 signal	With ignition switch ON (II): about 0.1 - 4.9 V (depending on engine coolant temperature)
2(1)	YEL/BLK (YEL)(3)	SLS (SHIFT LOCK SOLENOID)	Drives shift lock solenoid	With ignition switch ON (II), in the P position, brake pedal pressed, and accelerator released: about 0 V
2(2)	GRY	RVS (REVERSE LOCKOUT SOLENOID)	Drives reverse lockout solenoid	With vehicle speed below 9 mph (15 km/h): battery voltage With vehicle speed above 13 mph (20 km/h): about 0 V
3	BRN/YEL	LG3 (LOGIC GROUND)	Ground for ECM/PCM control circuit	Less than 1.0 V at all times
4	GRN/BLK	SG3 (SENSOR GROUND)	Sensor ground	Less than 1.0 Vat all times
5	YEL/GRN (GRN)(3)	VCC3 (SENSOR VOLTAGE)	Provides sensor voltage	With ignition switch ON (II): about 5.0 V With ignition switch OFF: about 0 V
7	RED/YEL (YEL)(3)	MRLY (PGM-FI MAIN RELAY)	Drives PGM-FI main relay 1 (Fl MAIN) Power source for DTC memory	With ignition switch ON (II): about 0 V With ignition switch OFF: battery voltage
8	ORN	AFSHTCR (AIR FUEL RATIO (A/F) SENSOR HEATER CONTROL RELAY)	Drives A/F sensor heater relay	With ignition switch ON (II): about 0 V
9	BLK/YEL	IG1 (IGNITION SIGNAL)	Detects ignition signal	With ignition switch ON (II): battery voltage With ignition switch OFF: about 0 V
11	WHT	CANH (CAN COMMUNICATION SIGNAL HIGH)	Sends communication signal	With ignition switch ON (II): pulses
12	GRN	FANC (RADIATOR FAN CONTROL)	Drives radiator fan relay	With radiator fan running: about 0 V With radiator fan stopped: battery voltage
14	LTGRN	FTP (FUEL TANK PRESSURE (FTP) SENSOR)	Detects FTP sensor signal	With ignition switch ON (II) and fuel fill cap open: about 2.5 V
15	BLU/BLK (BLU)(3)	ELD (ELECTRICAL LOAD DETECTOR)	Detects ELD signal	With ignition switch ON (II): about 0.1-4.8 V (depending on electrical load)
16	BLU/YEL (BLU)(3)	PSPSW (POWER STEERING PRESSURE SWITCH SIGNAL)	Detects PSP switch signal	At idle with steering wheel straight ahead: about 0 V At idle with steering wheel at full lock: battery voltage
17	GRN/YEL (GRN)(3)	IMOFPR (IMMOBILIZER FUEL PUMP RELAY)	Drives PGM-FI main relay 2 (FUEL PUMP)	0 V for 2 seconds after turning ignition switch ON (II), then battery voltage
18	RED	ACC (A/C CLUTCH RELAY)	Drives A/C clutch relay	With compressor ON: about 0 V With compressor OFF: battery voltage
19	LTGRN/RED	VSV (EVAPORATIVE EMISSION (EVAP) CANISTER VENT SHUT VALVE)	Drives EVAP canister vent shut valve	With ignition switch ON (II): battery voltage
20	WHT/RED	SHO2S (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S), SENSOR 2)	Detects secondary HO2S (sensor 2) signal	With throttle fully closed at idle and fully warmed up engine: above 0.6 V With throttle quickly closed: below 0.4 V
21	BLK/WHT (WHT)(3)	SO2SHTC (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S) HEATER CONTROL)	Drives secondary HO2S heater	With ignition switch ON (II): battery voltage With fully warmed up engine running: duty controlled
22	WHT/BLK	BKSW (BRAKE PEDAL POSITION SWITCH)	Detects brake pedal position switch signal	With brake pedal released: about 0 V With brake pedal pressed: battery voltage
23(5)	BLU	K-LINE	Sends and receives HDS signals	With ignition switch ON (II): pulses or battery voltage
24	RED	CANL (CAN COMMUNICATION SIGNAL LOW)	Sends the communication signal	With ignition switch ON (II): pulses
25(4)	BLU	NEP (ENGINE SPEED PULSE)	Outputs engine speed pulse	Not functional on USA and Canada models
26	BLU/WHT (BLU)(3)	VSSOUT (VEHICLE SPEED SENSOR OUTPUT SIGNAL)	Sends vehicle speed signal	Depending on vehicle speed: pulses With ignition switch ON (II): battery voltage
27	RED/BLU (RED)(3)	IMOCD (IMMOBILIZER CODE)	Detects immobilizer signal
29	BRN	SCS (SERVICE CHECK SIGNAL)	Detects service check signal	With the service check signal shorted using HDS: about 0 V With the service check signal open: about 5.0 V
30	RED/WHT (WHT)(3)	WEN (WRITE ENABLE SIGNAL)	Detects write enable signal	With ignition switch ON (II): about 0 V
(1) A/T (2) M/T (3) '06-08 models (4) '04-05 models (5) '04-06 models

Vacuum Hose Routing

Fig. 20: Identifying Vacuum Hose Routing
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Vacuum Distribution

Fig. 21: Identifying Vacuum Distribution
Courtesy of AMERICAN HONDA MOTOR CO., INC.

PGM-FI System

The programmed fuel injection (PGM-FI) system is a sequential multiport fuel injection system.

Air Conditioning (A/C) Compressor Clutch Relay

When the ECM/PCM receives a demand for cooling from the A/C system, it delays the compressor from being energized, and enriches the air fuel mixture to assure smooth transition to the A/C mode.

Air Fuel Ratio (A/F) Sensor

The A/F sensor operates over a wide air/fuel range. The A/F sensor is installed upstream of the TWC, and sends signals to the ECM/PCM which varies the duration of fuel injection accordingly.

Fig. 22: Identifying Air Fuel Ratio (A/F) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Barometric Pressure (BARO) Sensor

The BARO sensor is inside the ECM/PCM. It converts atmospheric pressure into a voltage signal that modifies the basic duration of the fuel injection discharge.

Camshaft Position (CMP) Sensor B

CMP sensor B detects the position of the No. 1 cylinder as a reference for sequential fuel injection to each cylinder.

Fig. 23: Cross Sectional View Of Camshaft Position (CMP) Sensor B
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Crankshaft Position (CKP) Sensor

The CKP sensor detects crankshaft speed and is used by the ECM/PCM to determine ignition timing and timing for fuel injection of each cylinder as well as detecting engine misfire.

Fig. 24: Cross Sectional View Of Crankshaft Position (CKP) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Engine Coolant Temperature (ECT) Sensor ('04-05 models)/Engine Coolant Temperature (ECT) Sensors 1 and 2 ('06-08 models)

ECT sensor ('04-05 models)/ECT sensor 1 and 2 ('06-08 models) is a temperature dependent resistor (thermistor). The resistance decreases as the engine coolant temperature increases.

Fig. 25: Cross Sectional View Of Engine Coolant Temperature (ECT) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Ignition Timing Control

The ECM/PCM contains the memory for basic ignition timing at various engine speeds and manifold absolute pressures. It also adjusts the timing according to engine coolant temperature and intake air temperature.

Injector Timing and Duration

The ECM/PCM contains the memory for basic discharge duration at various engine speeds and manifold pressures. The basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors to obtain the final discharge duration.

By monitoring long term fuel trim, the ECM/PCM detects long term malfunctions in the fuel system and sets a diagnostic trouble code (DTC).

Intake Air Temperature (IAT) Sensor

The IAT sensor is a temperature dependent resistor (thermistor). The resistance of the thermistor decreases as the intake air temperature increases.

Fig. 26: Cross Sectional View Of Intake Air Temperature (IAT) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Knock Sensor

The knock control system adjusts the ignition timing to minimize knock.

Fig. 27: Cross Sectional View Of Knock Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness Codes)

The vehicle has certain "readiness codes" that are part of the on-board diagnostics for the emissions systems. If the vehicle's battery has been disconnected or gone dead, if the DTCs have been cleared, or if the ECM/PCM has been reset, these codes are reset. In some states, part of the emissions testing is to make sure these codes are set to complete. If all of them are not set to complete, the vehicle may fail the test, or the test cannot be finished.

To check if the readiness codes are set to complete, turn the ignition switch ON (II), but do not start the engine. The MIL will come on for 15-20 seconds. If it then goes off, the readiness codes are complete. If it flashes five times, one or more readiness codes are not complete. To set each code, drive the vehicle or run the engine as described in the procedures (see MALFUNCTION INDICATOR LAMP (MIL) INDICATION (IN RELATION TO READINESS CODES) ).

Manifold Absolute Pressure (MAP) Sensor

The MAP sensor converts manifold absolute pressure into electrical signals to the ECM/PCM.

Fig. 28: Cross Sectional View Of Manifold Absolute Pressure (MAP) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Output Shaft (Countershaft) Speed Sensor

This sensor detects countershaft speed.

Fig. 29: Cross Sectional View Of Output Shaft (Countershaft) Speed Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Secondary Heated Oxygen Sensor (Secondary HO2S)

The secondary HO2S detects the oxygen content in the exhaust gas downstream of the three way catalytic converter (TWC), and sends signals to the ECM/PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The ECM/PCM compares the HO2S output with the A/F sensor output to determine catalyst efficiency. The secondary HO2S is located on the TWC.

Fig. 30: Identifying Secondary Heated Oxygen Sensor (Secondary HO2S)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Electronic Throttle Control System

The throttle is electronically controlled by the electronic throttle control system. Refer to Electronic Throttle Control System Diagram to see a functional layout of the system.

Idle control: When the engine is idling, the ECM/PCM controls the throttle actuator to maintain the proper idle speed according to engine loads.

Acceleration control: When the accelerator pedal is pressed, the ECM/PCM opens the throttle valve depending on the accelerator pedal position (APP) sensor signal.

Cruise control: The ECM/PCM controls the throttle actuator to maintain set speed when the cruise control is operating. The throttle actuator takes the place of the cruise control actuator.

Accelerator Pedal Position (APP) Sensor

As the accelerator pedal position changes, the sensor varies the signal voltage to the ECM/PCM.

Fig. 31: Identifying Accelerator Pedal Position (APP) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Throttle Body

The throttle body is a single-barrel side draft type. The lower portion of the throttle valve is heated by engine coolant from the cylinder head to prevent icing of the throttle plate.

Fig. 32: Identifying Throttle Body
Courtesy of AMERICAN HONDA MOTOR CO., INC.

VTEC/VTC

• The i-VTEC has a VTC (variable valve timing control) mechanism on the intake camshaft in addition to the usual VTEC.

  This mechanism improves fuel efficiency and reduces exhaust emissions at all levels of engine speed, vehicle speed, and engine load.

• The VTEC mechanism changes the valve lift and timing by using more than one cam profile.
• The VTC changes the phase of the intake camshaft via oil pressure. It changes the intake valve timing continuously.

  Fig. 33: VTEC/VTC Graph
  Courtesy of AMERICAN HONDA MOTOR CO., INC.

DRIVING CONDITION

Driving Condition	VTC Control	Description
(1) Light-load	Base Position	For stable combustion, the cam angle is retarded and reduces the entry of exhaust gas into the cylinder.
(2) Medium/high-load	Advance Control	Cam phase angle is controlled to optimize valve timing, improving fuel efficiency, and reducing emissions.
(3) High speed	Advance-Base Position	To reduce the pumping loss, the intake valve is closed quickly. This helps the entry of air fuel mixture with a charging effect, maximizing engine power.

VTC System

• The VTC system makes continuous intake valve timing changes based on operating conditions.
• Intake valve timing is optimized to allow the engine to produce maximum power.
• Cam angle is advanced to obtain the EGR effect and reduce pumping loss. The intake valve is closed quickly to reduce the entry of the air/fuel mixture into the intake port and improve the charging effect.
• The system reduces the cam advance at idle, stabilizes combustion, and reduces engine speed.
• If a malfunction occurs, the VTC system control is disabled and the valve timing is fixed at the fully retarded position.

  Fig. 34: VTC System Chart
  Courtesy of AMERICAN HONDA MOTOR CO., INC.

VTEC System

• The VTEC system changes the cam profile to correspond to the engine speed. It maximizes torque at low engine speed and output at high engine speed.
• The low lift cam is used at low engine speeds, and the high lift cam is used at high engine speeds.

  Fig. 35: VTEC System Chart
  Courtesy of AMERICAN HONDA MOTOR CO., INC.

VTEC/VTC

System Diagram

Fig. 36: VTEC/VTC System Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Camshaft Position (CMP) Sensor A

CMP sensor A detects camshaft angle position for the VTC system.

Fig. 37: Cross Sectional View Of Camshaft Position (CMP) Sensor A
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Idle Control System

When the engine is cold, the A/C compressor is on, the transmission is in gear, the brake pedal is pressed, the power steering load is high, or the alternator is charging, the ECM/PCM sends signals to the throttle position to maintain the correct idle speed.

Brake Pedal Position Switch

The brake pedal position switch signals the ECM/PCM when the brake pedal is pressed.

Power Steering Pressure (PSP) Switch

The PSP switch signals the ECM/PCM when the power steering load is high.

Fuel Supply System

Fuel Cutoff Control

During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at engine speeds over 1,010 rpm (A/T: 1,042 rpm). Fuel cutoff control also occurs when the engine speed exceeds 7,300 rpm, regardless of the position of the throttle valve, to protect the engine from over-revving. When the vehicle is stopped, the ECM/PCM cuts the fuel at engine speeds over 7,300 rpm (A/T: 5,000 rpm). On a cold engine, fuel cut occurs at a lower engine speed.

Fuel Pump Control

When the ignition is turned on, the ECM/PCM grounds PGM-FI main relay 2 (FUEL PUMP) which feeds current to the fuel pump for 2 seconds to pressurize the fuel system. With the engine running, the ECM/PCM grounds PGM-FI main relay 2 (FUEL PUMP) and feeds current to the fuel pump. When the engine is not running and the ignition is on, the ECM/PCM cuts ground to PGM-FI main relay 2 (FUEL PUMP) which cuts current to the fuel pump.

PGM-FI Main Relay 1 and 2

PGM-FI main relay 1 (Fl MAIN) is energized whenever the ignition switch is ON (II) to supply battery voltage to the ECM/PCM, power to the injectors, and power for PGM-FI main relay 2 (FUEL PUMP). PGM-FI main relay 2 (FUEL PUMP) is energized to supply power to the fuel pump for 2 seconds when the ignition switch is turned ON (II), and when the engine is cranking or running.

Intake Air System

This system supplies air for engine needs.

Intake Air Bypass Control Thermal Valve

When the engine is cold, the intake air bypass control thermal valve sends air to the injector.

The amount of air is regulated by engine coolant temperature. Once the engine is hot, the intake air bypass control thermal valve closes, stopping air to the injector.

Fig. 38: Identifying Intake Air Bypass Control Thermal Valve
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Resonator

A resonator in the intake air duct provides additional silencing as air is drawn into the engine.

Catalytic Converter System

Three Way Catalytic Converter (TWC)

The TWC converts hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO₂ ), nitrogen (N2), and water vapor.

Fig. 39: Identifying Three Way Catalytic Converter (TWC)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Positive Crankcase Ventilation (PCV) System

The PCV valve prevents blow-by gasses from escaping into the atmosphere by venting them into the intake manifold.

Fig. 40: Identifying Positive Crankcase Ventilation (PCV) System
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Evaporative Emission (EVAP) Control System

Refer to Evaporative Emission (EVAP) Control Diagram to see the functional layout of the system.

EVAP Canister

The EVAP canister temporarily stores fuel vapor from the fuel tank until it can be purged from the EVAP canister into the engine and burned.

EVAP Canister Purge Valve

When the engine coolant temperature is below 131°F (55°C), the ECM/PCM turns off the EVAP canister purge valve which cuts vacuum to the EVAP canister.

Fuel Tank Pressure (FTP) Sensor

The FTP sensor converts fuel tank absolute pressure into an electrical input to the ECM/PCM.

Fig. 41: Cross Sectional View Of Fuel Tank Pressure (FTP) Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.

EVAP Canister Vent Shut Valve

The EVAP canister vent shut valve is on the EVAP canister.

The EVAP canister vent shut valve controls the venting of the EVAP canister.

Fig. 42: Cross Sectional View Of EVAP Canister Vent Shut Valve
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fuel Cap Warning Message ('06-08 models)

The ECM/PCM detects a loose or missing fuel fill cap as an evaporative system leak and alerts the driver by showing a warning message in the multi-information display.

First drive cycle

The first time a leak is detected a "TIGHTEN FUEL CAP" message appears in the multi-information display (A). To scroll to another message, press the select/reset button. The "TIGHTEN FUEL CAP" message will appear each time you restart the engine until the system turns the message off. Turn the engine off then replace or tighten the fuel fill cap until it clicks at least once.

Fig. 43: Identifying Fuel Cap Warning Message ('06-08 Models)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

To make the message go off (With the HDS)

Procedure

1. Tighten the fuel fill cap until it clicks.
2. Clear the Temporary DTC with the HDS.
3. Verify there is no leak by doing the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

To make the message go off (Without the HDS) ('06-07 models)

Procedure

1. Tighten the fuel fill cap until it clicks.
2. The message should go off after several days of normal driving.

To make the message go off (Without the HDS) ('08 model)

Procedure

1. Tighten the fuel fill cap until it clicks.
2. Turn the ignition switch ON (II), and then to LOCK (0).
3. Do step 2 above two more times.

Electronic Throttle Control System Diagram

The electronic throttle control system consists of the throttle actuator, the throttle position (TP) sensor A/B, the accelerator pedal position (APP) sensor A/B, the throttle actuator control module, and the ECM/PCM. The throttle is electronically controlled by this system.

Fig. 44: Electronic Throttle Control System Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Evaporative Emission (EVAP) Control Diagram

The EVAP controls minimize the amount of fuel vapor escaping to the atmosphere. Vapor from the fuel tank is temporarily stored in the EVAP canister until it can be purged from the canister into the engine and burned.

The EVAP canister is purged by drawing fresh air through it and into a port on the intake manifold.

The purging vacuum is controlled by the EVAP canister purge valve, which operates whenever engine coolant temperature is above 131°F (55°C).

Fig. 45: Evaporative Emission (EVAP) Control Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

ECM/PCM Circuit Diagram

Fig. 46: ECM/PCM Circuit Diagram (1 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 47: ECM/PCM Circuit Diagram (2 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 48: ECM/PCM Circuit Diagram (3 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 49: ECM/PCM Circuit Diagram (4 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 50: ECM/PCM Circuit Diagram (5 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 51: ECM/PCM Circuit Diagram (6 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 52: ECM/PCM Circuit Diagram (7 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 53: ECM/PCM Circuit Diagram (8 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 54: ECM/PCM Circuit Diagram (9 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 55: ECM/PCM Circuit Diagram (10 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 56: ECM/PCM Circuit Diagram (11 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 57: ECM/PCM Circuit Diagram (12 Of 12)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

How to Set Readiness Codes

Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness Codes)

The vehicle has certain "readiness codes" that are part of the on-board diagnostics for the emissions systems. If the vehicle's battery has been disconnected or gone dead, if the DTCs have been cleared, or if the ECM/PCM has been reset, these readiness codes are reset to incomplete. In some states, part of the emissions testing is to make sure these codes are set to complete. If all of them are not set to complete, the vehicle may fail the emission test, or the test cannot be finished.

To check if the readiness codes are set to complete, turn the ignition switch ON (II), but do not start the engine. The MIL will come on for 15-20 seconds. If it then goes off, the readiness codes are complete. If it flashes five times, one or more readiness codes are not set to complete. To set readiness codes from incomplete to complete, do the procedure for the appropriate code.

To check the status of a specific DTC system, check the OBD status in the DTC MENU with the HDS (see OBD STATUS ). This screen displays the code, the current data list of the enable criteria, and the status of the readiness testing.

Catalytic Converter Monitor and Readiness Code

NOTE:

Do not turn the ignition switch off during the procedure. All readiness codes are cleared when the battery is disconnected, if the DTCs have been cleared, or if the ECM/PCM is reset with the HDS. Low ambient temperatures or excessive stop-and-go traffic may increase the drive time needed to switch the readiness code from incomplete to complete. The readiness code will not switch to complete until all the enable criteria are met. If a fault in the secondary HO2S system caused the MIL to come on, the readiness code cannot be set to complete until you correct the fault.

Enable Criteria

• ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) at 158°F (70°C) or more.
• Intake air temperature (IAT) at 20°F (-7°C) or more.
• Vehicle speed sensor (VSS) above 25 mph (40 km/h).

Procedure

1. Connect the HDS to the vehicle's data link connector (DLC), and bring up the READINESS CODEs screen for Catalyst in the DTCs MENU.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. After about 5 miles (8 km), the readiness code should switch to complete.
4. If the readiness code is still not set to complete, check for a Temporary DTC with the HDS. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

Evaporative Emission (EVAP) Control System Monitor and Readiness Code

NOTE:

All readiness codes are cleared when the battery is disconnected, if the DTCs have been cleared, or if the ECM/PCM is reset with the HDS.

Enable Criteria

• Battery voltage is more than 10.5 V.
• Engine at idle.
• ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) between 176°F (80°C) and 212°F (100°C).
• MAP SENSOR less than 46.6 kPa (14 in.Hg, 350 mmHg).
• Vehicle speed 0 mph (0 km/h).
• IAT SENSOR between 32°F (0°C) and 212°F (100°C).

Procedure

1. Connect the HDS to the vehicle's data link connector (DLC).
2. Start the engine.
3. Select EVAP TEST in the INSPECTION MENU with the HDS, then select the FUNCTION TEST in the EVAP TEST MENU.
   • If the result is normal, readiness is complete.
   • If the result is not normal, go to the next step.
4. Check for a Temporary DTC. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

Air Fuel Ratio (A/F) Sensor Monitor and Readiness Code

NOTE:

Do not turn the ignition switch off during the procedure. All readiness codes are cleared when the battery is disconnected, if the DTCs have been cleared, or if the ECM/PCM is reset with the HDS.

Enable Criteria

ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) at 140°F (60°C) or more.

Procedure

1. Start the engine.
2. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. During the drive, decelerate (with the throttle fully closed) for 5 seconds. After about 3.5 miles (5.6 km), the readiness code should switch from incomplete to complete.
3. Check the readiness codes screen for the air fuel ratio (A/F) sensor in the DTCs MENU with the HDS.
   • If the screen shows complete, readiness is complete.
   • If the screen shows not complete, go to the next step.
4. Check for a temporary DTC. If there is no DTC, the enable criteria was probably not met. Select the DATA LIST. Check the ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) in the ALL DATA LIST with the HDS. If the ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) is less than 140°F (60°C), run the engine until it is more than 140°F (60°C), then repeat the procedure.

Air Fuel Ratio (A/F) Sensor Heater Monitor Readiness Code

NOTE:

All readiness codes are cleared when the battery is disconnected, if the DTCs have been cleared, or if the ECM/PCM is reset with the HDS.

Procedure

1. Start the engine, and let it idle for 1 minute. The readiness code should switch from incomplete to complete.
2. If the readiness code is still not set to complete, check for a Temporary DTC. If there is no DTC, repeat the procedure.

Misfire Monitor and Readiness Code

• This readiness code is always set to available because misfiring is continuously monitored.
• Monitoring pauses, and the misfire counter resets, if the vehicle is driven over a rough road.
• Monitoring also pauses, and the misfire counter holds at its current value, if the throttle position changes more than a predetermined value, or if driving conditions fall outside the range of any related enable criteria.

Fuel System Monitor and Readiness Code

• This readiness code is always set to available because the fuel system is continuously monitored during closed loop operation.
• Monitoring pauses when the catalytic converter, EVAP control system, and A/F sensor monitors are active.
• Monitoring also pauses when any related enable criteria are not being met. Monitoring resumes when the enable criteria is again being met.

Comprehensive Component Monitor and Readiness Code

This readiness code is always set to available because the comprehensive component monitor is continuously running whenever the engine is cranking or running.

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