DTC Troubleshooting

DTC Troubleshooting: P0651 (134-1)

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 PCM and these parts:�

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed sensor
- FTP sensor

4. Turn the ignition switch to LOCK (0).

5. Disconnect the connectors from these parts:

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed 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 reconnecting these parts, one at a time:

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed 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 PCM and the following parts, then go to step 1.

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed sensor
- FTP sensor

10. Turn the ignition switch to LOCK (0).

11. Jump the SCS line with the HDS.

12. Disconnect PCM connectors A (49P) and B (49P).

13. Check for continuity between body ground and PCM connector terminals A25 and B36 individually.









Is there continuity?

YES -

Repair a short in the wire between the PCM(A25 or B36) and each part that was disconnected in step 5, 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 PCM with the HDS.

18. Do the PCM idle learn procedure PCM Idle Learn Procedure.

19. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0651 indicated?

YES -

Check for poor connections or loose terminals at the PCM and the following parts, then go to step 1.

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed sensor
- FTP sensor

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 PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.

22. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0651 indicated?

YES -

If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, check for poor connections or loose terminals at the PCM and the following parts, then go to step 1.

- APP sensor
- MAP sensor
- Output shaft (countershaft) speed sensor
- FTP sensor

NO -

If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�