DTC P0121 (19-21 9-Speed A/T)

DTC P0121  : Throttle Position (TP) Sensor A Out of Range

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

DTC (PGM-FI)

1. Problem verification 1

   -1. Turn the vehicle to the ON mode.

   - 2. Clear the DTC with the HDS.

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

   - 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
   TP Sensor A	Less than 0.38	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
   TP Sensor A	More than 4.50	V

   Do the current condition (s) match the threshold?

   YES 

   The failure is duplicated. Go to step 7.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the throttle body 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 (THL1 line, others)

   -1. Check for Pending or Confirmed DTCs with the HDS.

   DTC Description	Confirmed DTC	Pending DTC
   P0121 Throttle Position (TP) Sensor A Out of Range

   DTC Description	Confirmed DTC	Pending DTC
   P0221 Throttle Position (TP) Sensor B Out of Range

   Are DTC P0121 and P0221 indicated at the same time?

   YES 

   Go to step 5.

   NO 

   Go to step 4.

4. Shorted wire check (THL1 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 connectors.

   PCM connector E (80P)

   Throttle body 6P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector E (80P): disconnected
   	Throttle body 6P connector: disconnected
   Test point 1	Throttle body 6P connector (female terminals) No. 6:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short in the THL1 wire between the PCM (E72) and the throttle body.

   NO 

   The THL1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

5. Determine possible failure area (throttle body, others)

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

   - 2. Disconnect the following connector.

   Throttle body 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
   	Throttle body 6P connector: disconnected

   Test point 1	Throttle body 6P connector (female terminals) No. 5:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5.0 V?

   YES 

   Replace the throttle body .

   NO 

   Go to step 6.

6. 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 E (80P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Throttle body 6P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	Throttle body 6P connector (female terminals) No. 5:
   Test point 2	PCM connector E (80P) No. 68 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .

   Courtesy of HONDA, U.S.A., INC.

   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 - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

   NO 

   Repair an open in the VCC3 wire between the PCM (E68) and the throttle body.

7. Determine possible failure area (SG3 line, others)

   -1. Check for Pending or Confirmed DTCs with the HDS.

   DTC Description	Confirmed DTC	Pending DTC
   P0121 Throttle Position (TP) Sensor A Out of Range

   DTC Description	Confirmed DTC	Pending DTC
   P0221 Throttle Position (TP) Sensor B Out of Range

   Are DTC P0121 and P0221 indicated at the same time?

   YES 

   Go to step 10.

   NO 

   Go to step 8.

8. Determine possible failure area (throttle body, others)

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

   - 2. Disconnect the following connector.

   Throttle body 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
   	Throttle body 6P connector: disconnected
   Test point 1	Throttle body 6P connector (female terminals) No. 6:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5.0 V?

   YES 

   Replace the throttle body .

   NO 

   Go to step 9.

9. Open wire check (THL1 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 E (80P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Throttle body 6P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	Throttle body 6P connector (female terminals) No. 6:
   Test point 2	PCM connector E (80P) No. 72 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The THL1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

   NO 

   Repair an open in the THL1 wire between the PCM (E72) and the throttle body.

10. Open wire check (SG3 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 connectors.

    PCM connector E (80P)

    Throttle body 6P connector

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

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector E (80P): disconnected
    	Throttle body 6P connector: disconnected
    Test point 1	Throttle body 6P connector (female terminals) No. 3:
    Test point 2	PCM connector E (80P) No. 67 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021), .

    Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The SG3 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

    NO 

    Repair an open in the SG3 wire between the PCM (E67) and the throttle body.