DTC 37-1
DTC 37-1: Engine RPM Signal Circuit1. Clear the DTCs.
2. Test-drive the vehicle, and watch the VTM-4 indicator.
Does the VTM-4 indicator come on?
YES - Go to step 3.
NO - The system is OK at this time.
3. Watch the MIL.
Does the MIL come on?
YES - Check the fuel and emission system for DTCs.
NO - Go to step 4.
4. Disconnect connector A (22P) from the VTM-4 control unit.
5. Measure the voltage between the A12 terminal and body ground with the engine running.
Is the voltage correct?
YES - Go to step 13.
NO - Go to step 6.
6. Turn the ignition switch OFF.
7. Disconnect PCM connector B (56P) and gauge assembly connector A (30P).
8. Turn the ignition switch ON (II).
9. Measure the 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 B27 terminal of the PCM.
NO - Go to step 10.
10. Turn the ignition switch OFF.
11. 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 B27 terminal of the PCM, and the A13 terminal of the gauge assembly.
NO - Go to step 12.
12. Connect the A12 terminal of the VTM-4 control unit connector A (22P) to body ground with the jumper wire, then check for continuity between the B27 terminal of the PCM, the A13 terminal of the gauge assembly, and body ground.
Is there continuity ?
YES - Go to step 13.
NO - Repair open in the wire between the A12 terminal of the VTM-4 control unit, the B27 terminal of the PCM, and the A13 terminal of the gauge assembly.
13. Check for loose terminal fit in the VTM-4 control unit, PCM connectors, and the gauge assembly connectors. If it is normal, replace the VTM-4 control unit. Test-drive the vehicle, and watch the VTM-4 indicator.
Does the VTM-4 indicator come on?
YES - Replace the PCM or gauge assembly.
NO - The system is OK at this time.