DTC Troubleshooting

DTC Troubleshooting: P0651, 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 Pending or Confirmed 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 the connectors of these parts:�

- 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 the connectors of these parts:

- 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 Pending or Confirmed DTCs with the HDS.

Is DTC P0651 indicated?

YES -

Go to step 10.

NO -

Go to step 9.

9. Check for Pending or Confirmed DTCs with the HDS while connecting each connectors of these parts:

- 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 part that caused the DTC when it was reconnected, then go to step 14.

NO -

Check for poor connections or loose terminals at the ECM/PCM and the connectors of these parts:

- 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.

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 DTCs with the HDS.

Is DTC P0651 indicated?

YES -

Check for poor connections or loose terminals at the ECM/PCM and the connectors of these parts:

- 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 Pending or Confirmed 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 Pending or Confirmed 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 the connectors of these parts:

- 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 Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�