DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0123

DTC P0123 : TP Sensor A Circuit High Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Check TP SENSOR A in the DATA LIST with the HDS.

Is there about 4.8 V or more?
-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 ECM/PCM.

2. Determine possible failure area (SG3 line, others):

Determine possible failure area (SG3 line, others)
-1. Check for Pending or Confirmed DTCs with the HDS.

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 (TH_1 line, throttle body):

Determine possible failure area (TH_1 line, throttle body)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Turn the ignition switch to ON (II).

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









Is there about 5.0 V?
-YES- Replace the throttle body Removal and Replacement, then do the repair verification.
-NO- Go to step 4.

4. Open wire check (TH_1 line):

Open wire check (TH_1 line)
-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





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









Is there continuity?
-YES- The TH_1 wire is OK. Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
-NO- Repair an open in the TH_1 wire between the ECM/PCM (C30) and the throttle body, then do the repair verification.

5. Open wire check (SG3 line):

Open wire check (SG3 line)
-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connectors.





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









Is there continuity?
-YES- The SG3 wire is OK. Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
-NO- Repair an open in the SG3 wire between the ECM/PCM (C14) and the throttle body, then do the repair verification.

Repair verification:

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the ECM/PCM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM/PCM idle learn procedure. ECM/PCM Idle Learn Procedure

-6. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0123 indicated?
-YES- Check for poor connections or loose terminals at the throttle body and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM Service and Repair, then recheck. If the ECM/PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.