DTC P0123 (6-Speed A/T, '16-'18 9-Speed A/T)

DTC P0123  : TP Sensor A Circuit High Voltage

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. Turn the vehicle to the ON mode.

   - 2. Clear the DTC with the HDS.

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

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   TP SENSOR A	More than 4.8	V

   Do the current condition (s) match the threshold?

   YES 

   The failure is duplicated. Go to step 2.

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

2. Determine possible failure area (SG5 line, others)

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

   DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
   P0123 TP Sensor A Circuit High Voltage
   P0223 TP Sensor B Circuit High Voltage

   Are DTC P0123 and P0223 indicated at the same time?

   YES 

   Go to step 5.

   NO 

   Go to step 3.

3. Determine possible failure area (THL1 line, throttle body)

   -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 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 4.

4. 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 B (51P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Throttle body 6P connector: disconnected
   	PCM connector B (51P): disconnected
   Test point 1	Throttle body 6P connector No. 6
   Test point 2	PCM connector B (51P) No. 31 - Refer to: PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020), or PCM Connector for Inputs and Outputs (9-Speed A/T) (2016 2017 2018)

   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 (6-Speed A/T), (9-Speed A/T 2016 2017 2018) .

   NO 

   Repair an open in the THL1 wire between the PCM (B31) and the throttle body.

5. Open wire check (SG5 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 B (51P)

   Throttle body 6P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector B (51P): disconnected
   	Throttle body 6P connector: disconnected
   Test point 1	Throttle body 6P connector No. 3
   Test point 2	PCM connector B (51P) No. 46 - Refer to: PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020), or PCM Connector for Inputs and Outputs (9-Speed A/T) (2016 2017 2018)

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

   Is there continuity?

   YES 

   The SG5 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 (6-Speed A/T), (9-Speed A/T 2016 2017 2018) .

   NO 

   Repair an open in the SG5 wire between the PCM (B46) and the throttle body.