DTC Troubleshooting
DTC Troubleshooting: P0651
DTC P0651: Sensor Reference Voltage B Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0651 indicated?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the ECM/PCM and these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
4. Turn the ignition switch to LOCK (0).
5. Disconnect these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
6. Turn the ignition switch to ON (II).
7. Clear the DTC with the HDS.
8. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0651 indicated?
YES - Go to step 10.
NO - Go to step 9.
9. Check for Temporary DTCs or DTCs with the HDS while connecting each these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
Is DTC P0651 indicated?
YES - Replace the parts connected when the DTC is indicated, then go to step 14.
NO - Check for poor connections or loose terminals at the PCM and these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
If the connections and terminals are OK, go to step 1 and recheck.
10. Turn the ignition switch to LOCK (0).
11. Jump the SCS line with the HDS.
12. Disconnect ECM/PCM connectors A (49P), B (49P), and C (49P).
13. Check for continuity between body ground and ECM/PCM connector terminals A25, A36, B36, and C11 individually.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A25, A36, B36, or C11) and each sensor, then go to step 14.
NO - Go to step 20.
14. Turn the ignition switch to LOCK (0).
15. Reconnect all connectors.
16. Turn the ignition switch to ON (II).
17. Reset the ECM/PCM with the HDS.
18. Do the ECM/PCM idle learn procedure. ECM/PCM Idle Learn Procedure
19. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0651 indicated?
YES - Check for poor connections or loose terminals at the ECM/PCM and these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
If the connections and the terminals are OK, go to step 1 and recheck.
NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
20. Reconnect all connectors.
21. Update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM. Initial Inspection and Diagnostic Overview
22. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0651 indicated?
YES - If the ECM/PCM was updated, substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the ECM/PCM was substituted, check for poor connections or loose terminals at the ECM/PCM and these connectors:
- MAP sensor
- Output shaft (countershaft) speed sensor
- Rocker arm oil pressure sensor (J35Z2 engine)
- IMT actuator (J35Z3 engine)
- A/C pressure sensor
- APP sensor
- FTP sensor
If the connections and the terminals are OK, go to step 1.
NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. Service and Repair If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.