DTC 37-1

DTC 37-1, 38-1: Engine RPM Signal Circuit

NOTE: Before you troubleshoot, review the general troubleshooting information.

1. Turn the ignition switch ON (II).
2. Clear the DTCs with the HDS.
3. Test-drive the vehicle, and check for DTCs with the HDS.
Is DTC 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 DTCs in the PGM-FI system with the HDS.
Are there any PGM-FI DTC's indicated?
YES - Go to the indicated DTC's troubleshooting.
NO - Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the VTM-4 control unit connector A (22P) from the VTM-4 control unit.
7. Turn the ignition switch OFF.
8. Measure voltage between the A12 terminal of the VTM-4 control unit and body ground.





YES - Go to step 18.
NO - Go to step 9.
9. Turn the ignition switch OFF.
10. Jump the SCS line with the HDS.
11. Disconnect PCM connector A (44P).
12. Turn the ignition switch ON (II).
13. Measure voltage between the A12 terminal of the VTM-4 control unit and body ground.





Is there voltage?
YES - Repair short to power in the wire between the A12 terminal of the VTM-4 control unit and the A28 terminal of the PCM.
NO - Go to step 14.
14. Turn the ignition switch OFF.
15. Check for continuity between the A12 terminal of the VTM-4 control unit and body ground.





Is there continuity?
YES - Repair short to ground in the wire between the A12 terminal of the VTM-4 control unit, the A28 terminal of the PCM.
NO - Go to step 16.
16. Connect the A12 terminal of the VTM-4 control unit connector A (22P) to body ground with the jumper wire.





17. Check for continuity between PCM connector terminal A28 and body ground.





Is there continuity?
YES - Go to step 18.
NO - Repair open in the wire between the A12 terminal of the VTM-4 control unit and the A28 terminal of the PCM.
18. Check for loose terminal fit in the VTM-4 control unit, PCM connectors. If it is normal, replace the VTM-4 control unit. Test-drive the vehicle, and check for DTCs with the HDS.
Is DTC 37-1 and/or 38-1 indicated?
YES - Replace the PCM .
NO - The system is OK at this time.