DTC 38-1

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 DTC.
3. Test-drive the vehicle, and check for DTSs 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 OFF.
6. Disconnect VTM-4 control unit connector A (22P).
7. Turn the ignition switch ON (II).
8. Measure voltage between the No. 12 terminal of the VTM-4 control unit connector A (22P) and body ground with the engine running.








Is the voltage correct?

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 No. 12 terminal of the VTM-4 control unit connector A (22P) and body ground.





Is there voltage?

YES - Repair short to power in the wire between the VTM-4 control unit (Al2) and the PCM (A28).

NO - Go to step 14.

14. Turn the ignition switch OFF.
15. Check for continuity between the No. 12 terminal of the VTM-4 control unit connector A (22P) and body ground.





Is there continuity?

YES - Repair short to ground in the wire between the VTM-4 control unit (Al2), and the PCM (A28).

NO - Go to step 16.

16. Connect the No. 12 terminal of the VTM-4 control unit connector A (22P) to body ground with a jumper wire.





17. Check for continuity between the No. 28 terminal of the PCM connector A (44P) and body ground.





Is there continuity?

YES - Go to step 18.

NO - Repair open in the wire between the VTM-4 control unit (Al2), and the PCM (A28).

18. Check for poor connections or loose terminals at the VTM-4 control unit, and the PCM connectors. If the connections are OK, replace the VTM-4 control unit, then go to step 19.
19. Test-drive the vehicle, and watch the VTM-4 indicator.

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

YES - Replace the PCM.

NO - The system is OK at this time.