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| Illustration 1 | g00679810 |
Simplified Schematic For The Engine Coolant Temperature Sensor | |
Note: This schematic is not for EUI engines. The engine ECM monitors the coolant temperature on EUI engines. The engine ECM sends the information to the GSC. The following procedure DOES APPLY to EUI engines.
In order to find the cause of a high water temperature shutdown, perform the following procedure.
Test Step 1. CHECK FOR THE DIAGNOSTIC CODE.
- Check for the following active diagnostic codes: CID 110 (coolant temperature sensor) and CID 269 (sensor power supply). See Testing And Adjusting, "Troubleshooting Diagnostic Codes".
Expected Result:
CID 110 or CID 269 should not be showing. This means that CID 110 or CID 269 are not active.
Results:
- OK - CID 110 or CID 269 are not showing. Proceed to Test Step 2.
- NOT OK - CID 110 or CID 269 is active.
Repair: Correct the active CID 110 or CID 269 prior to proceeding with this procedure. See the topic Testing And Adjusting, "Troubleshooting Diagnostic Codes". On EUI engines, see Troubleshooting, SENR1003, "3500B EPG Engines", "P-503" or Troubleshooting, RENR2227, "3406E EPG Engines", "P-503".
Stop.
Test Step 2. CHECK OBVIOUS CAUSES.
- Check the water level.
- Check the fan drive belts.
- Check for other obvious causes of high water temperature.
Expected Result:
No obvious cause should exist.
Results:
- OK - No obvious causes were found. Proceed to Test Step 3.
- NOT OK - An obvious cause exists.
Repair: Correct the problem. Refer to the Engine Service Manual.
Stop.
Test Step 3. CHECK SETPOINT P15.
Note: Setpoint P15 describes high water temperature.
- View setpoint P15. Make a note of setpoint P15. See System Operation, "Engine/Generator Setpoint Viewing OP2-0".
- Compare the setpoints which are viewed with the specified setpoints of the particular generator set.
Expected Result:
The actual setpoint value and the specified setpoint value should agree.
Results:
- OK - The setpoints agree. Proceed to Test Step 4.
- NOT OK - The setpoints do NOT agree.
Repair: Reprogram setpoint P15. See System Operation, "Engine/Generator Programming OP5-0".
Stop.
Test Step 4. CHECK THE HIGH WATER TEMPERATURE FUNCTION.
- Turn the engine control switch (ECS) to OFF/RESET. Then, turn the ECS to START.
- Run the engine until the water temperature has stabilized.
- Check and note the actual water temperature which is showing on the lower display.
- Compare the actual temperature that is showing on the lower display with setpoint P15.
Note: It may be necessary to check the accuracy of the temperature that is shown on the lower display of the GSC. Install an accurate engine coolant temperature gauge. Install the sensor as close as possible to the EMCP II coolant temperature sensor.
Expected Result:
The actual temperature which is showing on the lower display should be less than setpoint P15. This actual temperature should not cause a high water temperature shutdown.
Results:
- Temp less than P15, indicator OFF - The actual temperature is less than the setpoint P15 and the high water temperature indicator does not FLASH.
Repair: The problem is not present now. The problem may be intermittent. Check the harness. Check all of the electrical connections of the water temperature circuit. See Testing And Adjusting, "Electrical Connector - Inspect".
Stop.
- Temp less than P15, indicator FLASHING - The actual temperature is less than the setpoint P15 and the high water temperature indicator remains FLASHING.
Repair: Therefore, the GSC has failed. Replace the GSC. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".
Stop.
- Temp higher than P15 - Actual temperature is greater than the setpoint P15.
Repair: The temperature is correct for a high water temperature shutdown. The engine should shutdown, and the indicator for high water temperature should FLASH. The GSC is operating properly. Refer to the Engine Service Manual in order to find the cause of high water temperature.
Stop.