Illustration 1 | g00564751 |
Schematic For The Temperature Sensor (Engine Coolant) |
Note: Ensure that the desired diagnostic code (CID FMI) is on hold. Ensure that the "SERV CODE" indicator is ON. The operator should use the electrical system schematic for the engine that is being serviced to find the connector contact on the main display module that corresponds to the current CID that is shown.
The diagnostic code is recorded when the Main Display Module reads an abnormal sensor signal. The sensor signal is not identifiable to the input circuitry of the Main Display Module. This diagnostic code will cause the corresponding Alert indicator to flash and the Gauge Needle will move into the warning region. The following examples are possible causes.
- The engine coolant temperature sensor has a problem.
- The ground circuit that is located in the engine harness is open.
- The signal circuit that is located in the engine harness is shorted to the +Battery terminal.
- The signal circuit in the engine harness is open or the connector is disconnected.
- The Main Display Module has a problem.
- Check The Display Area And The Harness.
- Turn the "ECS" switch to the OFF/RESET position.
- Check for loose terminal connections or corroded terminal connections.
- Clean corroded terminals and tighten loose connections.
- Turn the "ECS" switch to the COOLDOWN/STOP position. The "SERV CODE" indicator should be ON for CID 0110 FMI 08.
- Measure The Voltage Of The Supply Wire For The Engine Coolant Temperature Sensor.
- Turn the "ECS" switch to the COOLDOWN/STOP position.
- Use the 7X-1710 Multimeter Probe to measure the voltage from ground wire of the engine coolant temperature sensor (pin B) to the supply wire (pin A).
Expected Result: The voltage should be 8.0 ± 0.5 DCV.
Results:
- OK: The voltage is 8.0 ± 0.5 DCV. The voltage is correct. Proceed to Step 3.
- Not OK: The voltage is less than 8.0 ± 0.5 DCV. The harness wiring has a problem. There is an open circuit, a short to ground in the supply wire of the Engine Coolant Temperature Sensor, or a poor connection. Repair the harness or replace the harness. If the cause of the diagnostic code is not found, proceed to Step 3.
- OK: The voltage is 8.0 ± 0.5 DCV. The voltage is correct. Proceed to Step 3.
- Measure The Signal Voltage Of The Engine Coolant Temperature Sensor.
- Turn the "ECS" switch to the COOLDOWN/STOP position.
- Use the 7X-1710 Multimeter Probe to measure voltage from the ground wire of the Engine Coolant Temperature Sensor (pin B) to the supply wire (pin C).
Expected Result: The voltage should be between 1.0 DCV and 7.0 DCV.
Results:
- OK: The voltage is between 1.0 DCV and 7.0 DCV. The signal voltage at the sensor is correct. Proceed to Step 4.
- Not OK: The voltage is NOT between 1.0 DCV and 7.0 DCV. The signal voltage at the sensor is not correct. If the voltage is greater than 7.0 DCV, proceed to Step 5. If the voltage is less than 1.0 DCV, proceed to Step 6.
- OK: The voltage is between 1.0 DCV and 7.0 DCV. The signal voltage at the sensor is correct. Proceed to Step 4.
- Measure The Signal Voltage of the Temperature Sensor (Engine Coolant) at the Main Display Module.
- Turn the "ECS" switch to the COOLDOWN/STOP position.
- Use the 7X-1710 Multimeter Probe to measure the voltage from the ground wire of the Main Display Module to the signal wire connector contact.
Expected Result: The voltage that is measured should be similar to the voltage from Step 3.
Results:
- OK: The voltage is similar to the voltage that was recorded in Step 3. The Main Display Module is receiving a valid signal voltage. The Main Display Module has a problem. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".
- Not OK: The voltage is not similar to the voltage that was measured in Step 3. The engine harness has an open circuit in the signal circuits or the ground circuits. Repair the engine harness or replace the engine harness.
- OK: The voltage is similar to the voltage that was recorded in Step 3. The Main Display Module is receiving a valid signal voltage. The Main Display Module has a problem. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".
- Check For A Short To The Engine's +Battery Terminal.
- Turn the "ECS" switch to the OFF/RESET position.
- Disconnect the connector for the Main Display Module and disconnect the connector for the Engine Coolant Temperature Sensor.
- Use the 7X-1710 Multimeter Probe to measure the resistance that is between the +Battery terminal and the signal wire (pin C) for the Engine Coolant Temperature Sensor.
Expected Result: The resistance should be greater than 5000 ohms.
Results:
- OK: The resistance is greater than 5000 ohms. The signal wire is correct. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".
- Not OK: The resistance is less than 5000 ohms. Repair the harness or replace the harness.
- OK: The resistance is greater than 5000 ohms. The signal wire is correct. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".
- Check For A Short To Ground.
- Turn the "ECS" switch to the OFF/RESET position.
- Disconnect the connector for the Main Display Module and the connector for the Engine Coolant Temperature Sensor.
- Use the 7X-1710 Multimeter Probe to measure the resistance between ground and the signal wire (pin C) for the Engine Coolant Temperature Sensor.
Expected Result: The resistance should be greater than 5000 ohms.
Results:
- OK: The resistance is greater than 5000 ohms. The signal wire is correct. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".
- Not OK: The resistance is less than 5000 ohms. Repair the harness or replace the harness.
- OK: The resistance is greater than 5000 ohms. The signal wire is correct. Replace the Main Display Module. For more information, see Testing And Adjusting, "Module - Replace".