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DTC P2121 (19-21 9-Speed A/T)

DTC P2121  : Accelerator Pedal Position (APP) Sensor A (Throttle Position (TP) Sensor D) Out of Range

NOTE:  Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems .

DTC Description Confirmed DTC Pending DTC
P2121 Accelerator Pedal Position (APP) Sensor A (Throttle Position (TP) Sensor D) Out of Range    

DTC (PGM-FI)

  1. Problem verification 1

    - 1. Turn the vehicle to the ON mode.

    - 2. Check the parameter (s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    APP Sensor A Less than 0.69 V    

    Do the current condition (s) match the threshold?

    YES 

    The failure is duplicated. Go to step 3.

    NO 

    Go to step 2.

  2. Problem verification 2

    - 1. Check the parameter (s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    APP Sensor A More than 4.99 V    

    Do the current condition (s) match the threshold?

    YES 

    The failure is duplicated. Go to step 8.

    NO 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the APP sensor and the PCM.

    If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot - Refer to: How to Troubleshoot the Fuel and Emissions Systems .

  3. Determine possible failure area (VCC3 line, others)

    - 1. Turn the vehicle to the OFF (LOCK) mode.

    - 2. Disconnect the following connector.

    APP sensor 6P connector

    - 3. Turn the vehicle to the ON mode.

    - 4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    APP sensor 6P connector: disconnected
    Test point 1 APP sensor 6P connector (female terminals) No. 4:
    Test point 2 APP sensor 6P connector (female terminals) No. 5:
    GHH307924Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    Go to step 4.

    NO 

    Go to step 7.

  4. Shorted wire check (APS1 line)

    - 1. Turn the vehicle to the OFF (LOCK) mode.

    - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 3. Disconnect the following connector.

    PCM connector A (50P)

    - 4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    PCM connector A (50P): disconnected
    Test point 1 APP sensor 6P connector (female terminals) No. 6:
    Test point 2 Body ground
    GHH307925Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the APS1 wire between the PCM (A33) and the APP sensor.

    NO 

    The APS1 wire is not shorted. Go to step 5.

  5. Open wire check (APS1 line)

    - 1. Connect terminals A and B with a jumper wire.

    Terminal A APP sensor 6P connector (female terminals) No. 6:
    Terminal B Body ground
    GHH307926Courtesy of HONDA, U.S.A., INC.

    - 2. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    PCM connector A (50P): disconnected
    APP sensor 6P connector No. 6: jumped to body ground
    Test point 1 PCM connector A (50P) No. 33 - Refer to:
    PCM Connector for Inputs and Outputs (19-21 9-Speed A/T)
    Test point 2 Body ground

    Is there continuity?

    YES 

    The APS1 wire is OK. Go to step 6.

    NO 

    Repair an open in the APS1 wire between the PCM (A33) and the APP sensor.

  6. PCM internal circuit check

    - 1. Remove the jumper wire from the APP sensor 6P connector.

    - 2. Reconnect the following connector.

    PCM connector A (50P)

    - 3. Connect terminals A and B with a jumper wire.

    Terminal A APP sensor 6P connector (female terminals) No. 4:
    Terminal B APP sensor 6P connector (female terminals) No. 6:
    GHH307927Courtesy of HONDA, U.S.A., INC.

    - 4. Turn the vehicle to the ON mode.

    - 5. Check the parameter (s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    APP Sensor A Less than 0.69 V    

    Do the current condition (s) match the threshold?

    YES 

    Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T) .

    If DTC P2121 goes away and the PCM was substituted, replace the original PCM - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T) .

    NO 

    Replace the accelerator pedal module .

  7. Open wire check (VCC3 line)

    - 1. Turn the vehicle to the OFF (LOCK) mode.

    - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 3. Disconnect the following connector.

    PCM connector A (50P)

    - 4. Connect terminals A and B with a jumper wire.

    Terminal A APP sensor 6P connector (female terminals) No. 4:
    Terminal B Body ground
    GHH307928Courtesy of HONDA, U.S.A., INC.

    - 5. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    PCM connector A (50P): disconnected
    APP sensor 6P connector No. 4: jumped to body ground
    Test point 1 PCM connector A (50P) No. 48 - Refer to:
    PCM Connector for Inputs and Outputs (19-21 9-Speed A/T)
    Test point 2 Body ground

    Is there continuity?

    YES 

    The VCC3 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T)

    If DTC P2121 goes away and the PCM was substituted, replace the original PCM - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T) .

    NO 

    Repair an open in the VCC3 wire between the PCM (A48) and the APP sensor.

  8. Determine possible failure area (APP sensor, others)

    - 1. Turn the vehicle to the OFF (LOCK) mode.

    - 2. Disconnect the following connector.

    APP sensor 6P connector

    - 3. Turn the vehicle to the ON mode.

    - 4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    APP sensor 6P connector: disconnected
    Test point 1 APP sensor 6P connector (female terminals) No. 4:
    Test point 2 APP sensor 6P connector (female terminals) No. 5:
    GHH307929Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    Replace the accelerator pedal module .

    NO 

    Go to step 9.

  9. Open wire check (PGND line)

    - 1. Turn the vehicle to the OFF (LOCK) mode.

    - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

    - 3. Disconnect the following connector.

    PCM connector A (50P)

    - 4. Connect terminals A and B with a jumper wire.

    Terminal A APP sensor 6P connector (female terminals) No. 5:
    Terminal B Body ground
    GHH307930Courtesy of HONDA, U.S.A., INC.

    - 5. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    APP sensor 6P connector: disconnected
    PCM connector A (50P): disconnected
    APP sensor 6P connector No. 5: jumped to body ground
    Test point 1 PCM connector A (50P) No. 37 - Refer to:
    PCM Connector for Inputs and Outputs (19-21 9-Speed A/T)
    Test point 2 Body ground

    Is there continuity?

    YES 

    The PGND wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T)

    If DTC P2121 goes away and the PCM was substituted, replace the original PCM - Refer to:

    PCM Removal and Installation (19-21 9-Speed A/T) .

    NO 

    Repair an open in the PGND wire between the PCM (A37) and the APP sensor.

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