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.

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 (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 (A29) and the APP sensor, then do the repair verification.

5. ECM internal circuit check:

ECM 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 ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM 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 ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM Service and Repair, then do the repair verification.
-NO- Repair an open in the VCC5 wire between the ECM (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 with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM 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. If the ECM was updated, substitute a known-good ECM Service and Repair, then recheck. If the ECM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the ECM was substituted, replace the original ECM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.