 | |
| Illustration 1 | g00527377 |
System Schematic For Engine Coolant Temperature Sensor (ECTS) | |
The EMCP II+ monitors the engine coolant temperature in order to protect the engine from a problem with the coolant temperature. The coolant temperature sensor is mounted in the water jacket, close to the front of the engine. The exact location of the engine coolant temperature sensor varies depending on the engine model.
The sensor is powered by an 8 volt sensor supply from the GSC+. The coolant temperature signal is a pulse width modulated signal. The base frequency of the signal is 455 Hz (370 to 550 Hz). As temperature changes, the duty cycle of the signal varies from 10 to 95 percent.
- −40°C (−40°F) is approximately 10% of the duty cycle. The voltage is approximately 1.0 DCV.
- 135°C (275°F) is approximately 93% of the duty cycle.
System Response:
Note: The GSC+ is usually programmed to treat a fault with the coolant temperature sensor as an alarm fault. P004is set to 0 for the factory default. The GSC+ is programmed to shutdown when P004 is set to 1. If the GSC+ is programmed to shutdown for a fault with the coolant temperature sensor, then the operator is not required to press the "Alarm Codes" key in order to view the CID 0110 FMI 03. The CID 0110 FMI 03 is automatically shown on the upper display.
The possible causes of a CID 0110 FMI 03 fault are listed below:
- A short to +battery of the sensor signal.
- An open circuit of the sensor signal.
Begin performing these procedures only when CID 0110 FMI 03 is showing and the "DIAG" indicator is FLASHING on the upper display. The flashing "DIAG" indicator means that the fault is active. The GSC+ treats a CID 0110 FMI 03 fault as an alarm fault. Active alarm faults are shown on the display when the "Alarm Codes" key is pressed and the engine control switch (ECS) is in any position except the OFF/RESET position. For an inactive fault, use the preceding system schematic and see Testing And Adjusting, "Electrical Connector - Inspect". Clear the fault from the fault log after troubleshooting is complete.
Note: If a diagnostic code for the sensor supply (CID 0269) is active, correct the diagnostic code for the sensor supply prior to proceeding with this procedure.
Test Step 1. CHECK THE SUPPLY CIRCUIT.
- Turn the ECS to OFF/RESET and then turn the ECS to the STOP position.
- Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.
- At the engine harness side of the sensor connector, measure the voltage (DCV) that is between contact "A" and contact "B". Contact "A" is the supply for the sensor. Contact "B" is the ground for the sensor.
Expected Result:
The voltage should be 8.0 ± 0.5 DCV.
Results:
- OK - The voltage is 8.0 ± 0.5 DCV. The sensor voltage supply circuit functions properly. Proceed to Test Step 2.
- NOT OK - The voltage is not 8.0 ± 0.5 DCV. The sensor voltage supply circuit has failed. Check the upper display for a diagnostic code for the sensor supply (CID 0269). Correct the problem with the sensor supply. If there is not a problem with the sensor supply, then the engine harness has an open circuit. Proceed to Test Step 4.
Test Step 2. CHECK THE SIGNAL CIRCUIT.
- The ECS remains in the STOP and the sensor remains disconnected from the sensor harness. At the engine harness side of the sensor connector, measure the voltage (DCV) between contact "C" and contact "B". Contact "C" is the signal of the sensor. Contact "B" is the sensor ground.
Expected Result:
The voltage measures ...
Results:
- 7.0 ± 0.5 DCV - The voltage is 7.0 ± 0.5 DCV.
Repair: The signal circuit functions properly. Verify this result by checking the upper display for the fault. Reconnect the sensor. Turn the ECS to the OFF/RESET position and then turn the ECS to the STOP position. If the CID 0110 FMI 03 is still showing on the display, the sensor has failed. Replace the sensor.
STOP
- BATTERY VOLTAGE - The voltage is not 7.0 ± 0.5 DCV. Voltage is equal to + battery.
Repair: The engine harness has failed. The signal circuit within the engine harness is shorted to + battery. Troubleshoot and repair the engine harness.
STOP
- NOT 7.0 ± 0.5 DCV OR +BATTERY - The voltage is NOT 7.0 ± 0.5 DCV. The voltage is NOT equal to + battery. The GSC+ or the harness is faulty. Proceed to Test Step 3.
Test Step 3. CHECK FOR A SHORTED HARNESS.
Note: See illustration 1 when you are performing this step. The sensor remains disconnected from the engine harness.
- Turn the ECS to the OFF/RESET position.
- Disconnect the harness connector from the GSC+.
- At the GSC+ harness connector, measure the resistance from signal contact "7" to all other contacts of the connector.
Expected Result:
For each measurement, the resistance should be greater than 5000 ohms.
Results:
- OK - For each measurement, the resistance is greater than 5000 ohms. The harness functions properly. Proceed to Test Step 4.
- NOT OK - For each measurement, the resistance is not greater than 5000 ohms.
Repair: The harness wiring with the incorrect resistance is shorted in the harness. Troubleshoot and repair the failed harness wiring between the sensor and the GSC+ connector.
STOP
Test Step 4. CHECK FOR AN OPEN HARNESS.
Note: See illustration 1 when you are performing this step. The sensor remains disconnected from the engine harness. The ECS remains in the OFF/RESET position. The sensor remains disconnected from the engine harness and the GSC+ remains disconnected from the harness connector.
- Measure the resistance of the ground circuit. The measurement should be taken from contact "B" of the sensor harness connector to contact "31" of the GSC+ harness connector.
- Measure the resistance of the signal circuit. The measurement should be taken from contact "C" of the sensor harness connector to contact "7" of the GSC+ harness connector.
- Measure the resistance of the sensor supply circuit. The measurement should be taken from contact "A" of the sensor harness connector to contact "9" of the GSC+ harness connector.
Expected Result:
For each measurement, the resistance should be 5 ohms or less.
Results:
- OK - For each measurement, the resistance is 5 ohms or less. The harness functions properly. Proceed to Test Step 5.
- NOT OK - For each measurement, the resistance is not 5 ohms or less.
Repair: The harness wiring with the incorrect resistance measurement is open. The harness wiring has failed. Troubleshoot and repair the failed harness wiring between the sensor connector and the GSC+ connector.
STOP
Test Step 5. CHECK THE ELECTRICAL CONNECTORS.
- Check the electrical connectors, terminals and wiring. Proceed to Testing And Adjusting, "Electrical Connector - Inspect" for more information on checking the electrical connectors and wiring.
Expected Result:
All connectors, terminals and wiring should function properly.
Results:
- OK - All connectors, terminals and wiring function properly.
Repair: Connect all harness connectors that were previously disconnected. Start the engine. If the CID 0110 FMI 03 is still showing, the GSC+ may have failed. It is unlikely that the GSC+ has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".
STOP
- NOT OK - All connectors, terminals and wiring do not function properly.
Repair: Repair the component that has failed.
STOP