37-1

VTM-4 DTC Troubleshooting: 37-1, 38-1

DTC 37-1, 38-1:

Engine RPM Signal Circuit

NOTE: Before you troubleshoot, 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. Test-drive the vehicle, and check for DTCs with the HDS.

Is DTCs 37-1 and/or 38-1 indicated?

YES -

Go to step 4.

NO -

Intermittent failure, the system is OK at this time.�

4. Check for DTC's in the PGM-FI DTCs indicated

Are there any PGM-FI DTCs indicated?

YES -

Go to the indicated DTCs troubleshooting.�

NO -

Go to step 5.

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

6. Disconnect VTM-4 control unit connector A (22P).

7. Turn the ignition switch to ON (II).

8. Measure the voltage between VTM-4 control unit connector terminal A12 and body ground.










Is the voltage correct?

YES -

Go to step 18.

NO -

Go to step 9.

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

10. Jump the SCS line with the HDS.

11. Disconnect PCM connector A (44P).

12. Turn the ignition switch to ON (II).

13. Measure the voltage between VTM-4 control unit connector terminal A12 and body ground.





Is there voltage?

YES -

Repair a short to power in the wire between VTM-4 control unit connector terminal A12 and PCM connector terminal A33.�

NO -

Go to step 14.

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

15. Check for continuity between VTM-4 control unit connector terminal A12 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire between VTM-4 control unit connector terminal A12 and PCM connector terminal A33.�

NO -

Go to step 16.

16. Connect the VTM-4 control unit connector terminal A12 to body ground with a jumper wire.






17. Check for continuity between PCM connector terminal A33 and body ground.





Is there continuity?

YES -

Go to step 18.

NO -

Repair an open in the wire between VTM-4 control unit connector terminal A12, and PCM connector terminal A33.�

18. Reconnect all connectors.

19. Check for poor connections or loose terminals at the VTM-4 control unit, and the PCM connectors. If the connections are OK, substitute a known-good VTM-4 control unit Service and Repair and recheck. If the symptom/indication goes away with the known-good VTM-4 control unit, replace the original VTM-4 control unit Service and Repair, then go to step 20.

20. Test-drive the vehicle, and check for DTCs with the HDS.

Is DTCs 37-1 and/or 38-1 indicated?

YES -

Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM and recheck. If the symptom/indication goes away with the updated PCM, troubleshooting is complete. If the symptom/indication goes away a known-good PCM, replace the original PCM control unit Service and Repair.�

NO -

Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�