VTM-4 Indicator Light Circuit Troubleshooting
VTM-4 Indicator Light Circuit TroubleshootingThe VTM-4 indicator light comes on, but no DTC is stored.
1. Check the No. 6 (15A) fuse in the driver's under dash fuse/relay box.
Is the fuse OK?
YES - Go to step 2.
NO - Replace the fuse and recheck.
2. Reinitialize the VTM-4 control unit, and watch the VTM-4 indicator.
Does the VTM-4 indicator light come on and stay on?
YES - Go to step 3.
NO - The system is OK at this time.
3. Turn the ignition switch OFF.
4. Measure the voltage between the A12 and A10 terminals of the VTM-4 control unit, and between the B26 and B12 terminal of the VTM-4 control unit.
Is there battery voltage?
YES - Go to step 5.
NO - Repair open in the wire between A12 or B26 terminals of the VTM-4 control unit and the driver's underdash fuse/relay box, or repair open in the wire between A10 or B12 terminals of the VTM-4 control unit and body ground.
5. Turn the ignition switch OFF.
6. Disconnect the VTM-4 control unit and the gauge assembly connectors.
7. Check for continuity between the A14 and B20 terminals of the VTM-4 control unit and body ground.
Is there continuity?
YES - Repair short to ground in the wire between the A14 or B20 terminals of the VTM-4 control unit and the gauge assembly.
NO - Go to step 8.
8. Reconnect the gauge assembly connectors only, then turn the ignition switch ON (II).
Does the VTM-4 indicator light come on?
YES - Replace the gauge assembly.
NO - Check for loose terminal fit in VTM-4 connectors. If it is normal, replace the VTM-4 control unit.
The VTM-4 indicator light does not come on.
1. Turn the ignition switch ON (II), and check for operation all gauge assembly indicator lights.
Do the indicator lights come on?
YES - Go to step 2.
NO - Check for open or short in the power and ground circuits in the gauge assembly.
2. Disconnect the A (22P) and B (26P) connectors from the VTM-4 control unit.
3. Turn the ignition switch ON (II).
4. Connect the A14 or B20 terminals of the VTM-4 control unit to body ground with a jumper wire, and watch the VTM-4 indicator light.
Does the VTM-4 indicator light come on?
YES - Check for loose terminal fit in the VTM-4 control unit connectors. If it is normal, replace the VTM-4 control unit.
NO - Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the A (22P) and B (30P) connectors from the gauge assembly.
7. Connect the B20 terminal of the gauge assembly to body ground with a jumper wire, then check for continuity between the A14 and B20 terminals of the VTM-4 control unit and body ground.
Is there continuity?
YES - Check for a blown bulb in the VTM-4 indicator light or a problem in gauge assembly.
NO - Repair open in the wire between the A7 terminal of the gauge assembly and driver's underdash fuse/relay box.