The possible causes of this fault are listed here:
- The sensor is faulty.
- The ground circuit in the machine harness is open.
- The signal circuit in the machine harness is shorted to the +battery circuit.
- The signal circuit in the machine harness is open or the sensor is disconnected.
- The VIMS module is faulty. This is unlikely.
- CHECK THE CONTROL AND THE HARNESS.
- Turn the disconnect switch and the key start switch to the ON position.
- Disconnect the machine harness from the sensor.
- At the machine harness connector for the sensor, measure the voltage (DCV) between the signal contact and the ground contact.
Expected Result: The voltage is 5.0 ± 0.5 DCV.
Results:
- OK - Voltage is 5.0 ± 0.5 DCV. The VIMS module is correct and the harness is correct. The sensor is faulty. Replace the sensor. Refer to the Testing and Adjusting, "Pulse Width Modulated (PWM) Sensor - Test" section. STOP.
- NOT OK - Voltage is NOT 5.0 ± 0.5 DCV. The VIMS module is faulty or the harness is faulty. Proceed to Step 2.
- CHECK THE GROUND CIRCUIT IN THE HARNESS.
The machine harness remains disconnected from the sensor.
- Turn the key start switch and turn the disconnect switch to the OFF position.
- Disconnect the machine harness from the VIMS module.
- At the machine harness connector for the sensor, measure the resistance between the ground contact and frame ground.
Expected Result: The resistance is less than 5.0 ohms.
Results:
- OK - Resistance is less than 5.0 ohms. The harness resistance is correct. Proceed to Step 3.
- NOT OK - Resistance is greater than 5.0 ohms. The ground circuit in the harness is faulty. There is an open circuit between the ground contact and frame ground. Repair the machine harness or replace the machine harness. STOP.
- CHECK THE SIGNAL CIRCUIT FOR A SHORT IN THE HARNESS.
The sensor remains disconnected from the machine harness. The VIMS module remains disconnected from the machine harness. The disconnect switch remains in the OFF position. The key start switch remains in the OFF position.
- At the machine harness connector for the sensor, measure the resistance between the signal contact and the +battery contact (+V).
Expected Result: The resistance is greater than 5000 ohms.
Results:
- OK - Resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Step 4.
- NOT OK - Resistance is less than 5000 ohms. The machine harness is faulty. There is a short between the +battery circuit and the signal circuit in the machine harness. Repair the machine harness or replace the machine harness. STOP.
- At the machine harness connector for the sensor, measure the resistance between the signal contact and the +battery contact (+V).
- CHECK THE SIGNAL CIRCUIT FOR AN OPEN IN THE HARNESS.
The sensor remains disconnected from the machine harness and the VIMS module remains disconnected from the machine harness. The disconnect switch remains in the OFF position and the key start switch remains in the OFF position.
- Measure the resistance of the signal circuit from the VIMS machine harness connector to the sensor machine harness connector.
Expected Result: The resistance is less than 5.0 ohms (continuity).
Results:
- OK - Circuit has continuity. The signal circuit is correct. The VIMS module is faulty. Replace the VIMS module. Refer to the Testing and Adjusting, "Module - Replace " section. STOP.
- NOT OK - Circuit has NO continuity. The signal circuit is faulty. The signal circuit is open in the machine harness. Repair the machine harness or replace the machine harness. STOP.
- Measure the resistance of the signal circuit from the VIMS machine harness connector to the sensor machine harness connector.