DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P2127

DTC P2127 : APP Sensor B (TP Sensor E) Circuit Low 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. Check APP SENSOR B in the DATA LIST with the HDS.

Is there about 0.2 V or less?
-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 APP sensor and the ECM/PCM.

2. Determine possible failure area (VCC5 line, others):

Determine possible failure area (VCC5 line, others)
-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- Go to step 3.
-NO- Go to step 6.

3. Shorted wire check (APS2 line):

Shorted wire check (APS2 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- Repair a short in the APS2 wire between the ECM/PCM (A29) and the APP sensor, then do the repair verification.
-NO- The APS2 wire is not shorted. Go to step 4.

4. Open wire check (APS2 line):

Open wire check (APS2 line)
-1. Connect terminals A and B with a jumper wire.









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









Is there continuity?
-YES- The APS2 wire is OK. Go to step 5.
-NO- Repair an open in the APS2 wire between the ECM/PCM (A29) and the APP sensor, then do the repair verification.

5. ECM/PCM internal circuit check:

ECM/PCM internal circuit check
-1. Reconnect the following connector.





-2. Connect terminals A and B with a jumper wire.









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

-4. Check APP SENSOR B in the DATA LIST with the HDS.

Is there about 0.2 V or less?
-YES- 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- Replace the APP sensor Service and Repair, then do the repair verification.

6. Open wire check (VCC5 line):

Open wire check (VCC5 line)
-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





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









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









Is there continuity?
-YES- The VCC5 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 VCC5 wire between the ECM/PCM (A35) and the APP sensor, 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 P2127 indicated?
-YES- Check for poor connections or loose terminals at the APP Sensor 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.