Electronic Modular Control Panel II+ (EMCP II+) for EUI Engines Caterpillar

Illustration 1	g00527377
System Schematic For Engine Coolant Temperature Sensor

The EMCP II+ monitors engine coolant temperature in order to protect the engine in case of a coolant temperature problem. 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. This is approximately 1.0 DCV.

• 135°C (275°F) is approximately 93% of the duty cycle.

Note: The GSC+ is usually programmed to treat a coolant temperature sensor fault as an alarm fault. P004 = 0 is the factory default. If the GSC+ is programmed to shutdown for a coolant temperature sensor fault, then it is not necessary to press the "Alarm Codes" key in order to view the CID 110 FMI 2. P004 = 1 is a shutdown. The CID 110 FMI 2 is automatically shown on the upper display.

Note: Faults are created when the harness connector is disconnected from the GSC+ during these troubleshooting procedures. Clear these created faults after the particular fault is corrected and the fault is cleared. In a properly operating system, when the harness connector is removed from the GSC+, the following diagnostic fault codes are recorded.

CID 100 FMI 2 - Pressure Sensor (Engine Oil)

CID 110 FMI 2 - Temperature Sensor (Engine Coolant)

CID 111 FMI 3 - Fluid Level Sensor (Engine Coolant)

CID 175 FMI 3 - Temperature Sensor (Engine Oil)

CID 190 FMI 3 - Speed Sensor (Engine)

CID 336 FMI 2 - Switch (Engine Control)

CID 590 FMI 9 - Engine (ECM)

An FMI 2 describes an incorrect signal.

Note: A CID 111 FMI 3 and a CID 175 FMI 3 will only be recorded if the machine is equipped with the proper sensors.

The possible causes of a CID 110 FMI 2 fault are listed below:

• The base frequency of the sensor signal is beyond accepted limits.

• The duty cycle of the sensor signal is beyond accepted limits.

Begin to perform these procedures only when the CID 110 FMI 2 is showing and when the "DIAG" indicator is FLASHING on the upper display. The fault is active when the "DIAG" indicator is FLASHING. The GSC+ treats a CID 110 FMI 2 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, the problem may be intermittent. To troubleshoot 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: This procedure can be replaced by troubleshooting the sensor signal with a meter that is capable of measuring frequency and duty cycle. See Testing And Adjusting, "Pulse Width Modulated (PWM) Sensor - Test".

Note: If a sensor supply fault (CID 269) is active, correct the fault prior to proceeding with this procedure.

1. Check the GSC+ and the harness.

   Make sure that CID 110 FMI 2 is showing on the display.

   1. Turn the ECS to the OFF/RESET position.

   2. Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.

   3. Turn the ECS to the STOP position.

   4. Press the "Alarm Codes" key. Pressing the "Alarm Codes" key is not required for shutdown faults.

   5. Check if the CID 110 FMI 2 is not showing. The CID 110 FMI 2 is inactive. Check if the CID 110 FMI 3 is now showing. The CID 110 FMI 3 is active.

      Expected Result: The CID 110 FMI 2 is not showing. The CID 110 FMI 3 is now showing. The CID 110 FMI 3 is now active.

      Results

      • OK: The GSC+ and the harness function properly. Therefore, the sensor is faulty. Replace the sensor. More testing for the sensor is available. See Testing And Adjusting, "Pulse Width Modulated (PWM) Sensor - Test". STOP.

      • NOT OK: The CID 110 FMI 2 fault is still showing. The harness or the GSC+ is faulty. Proceed to Step 2.

2. Check the GSC+.

   1. Turn the ECS to the OFF/RESET position.

   2. Disconnect the harness connector from the GSC+.

   3. Turn the ECS to the STOP position.

   4. Press the "Alarm Codes" key.

   5. Check if the CID 110 FMI 2 is not showing. The CID 110 FMI 2 is inactive. Check if the CID 110 FMI 3 is now showing. The CID 110 FMI 3 is active.

      Expected Result: CID 110 FMI 2 is not showing. The CID 110 FMI 3 is now showing. The CID 110 FMI 3 is now active.

      Results:

      • OK: The GSC+ functions properly. Therefore, the signal wire is faulty in the harness. Troubleshoot the signal wire in the harness between the sensor connector and the GSC+ connector. Also check the electrical connectors and terminals. See Testing And Adjusting, "Electrical Connector - Inspect". STOP.

      • NOT OK: The CID 110 FMI 2 fault is still showing. The GSC+ is faulty. Replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace". STOP.