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

Illustration 1	g00529671
System Schematic For Engine Oil Temperature Sensor (EOTS)

The EMCP II+ monitors engine oil temperature in order to protect the engine in case of a problem with the oil temperature. The oil temperature sensor is mounted in an oil gallery of the engine. The exact location of the engine oil temperature sensor varies depending on the engine model.

The sensor is powered by an 8 volt sensor supply from the GSC+. The oil 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, which is approximately 1.0 DCV.

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

Note: The GSC+ is usually programmed to treat an oil temperature sensor fault as an alarm fault. The factory default for P004 is 0. The GSC+ may be programmed to shutdown for an oil temperature sensor fault. P004 is 1 for a shutdown. The operator is not required to press the Alarm Codes key in order to view the CID 175 FMI 2. The CID 175 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 particular fault is cleared. In a system that is operating properly, the following list of diagnostic fault codes are created when the harness connector is removed from the GSC+.

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)

The possible causes of a CID 175 FMI 2 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 performing these procedures only when CID 175 FMI 2 is showing and the "DIAG" indicator is FLASHING on the upper display. The GSC+ treats a CID 175 FMI 2 fault as an alarm fault. Active alarm faults are shown on the display when the "Alarm Codes" key is pressed. The engine control switch (ECS) must be in any position except the OFF/RESET position. For an inactive fault, the problem may be intermittent. In order to troubleshoot an inactive fault, use the preceding system schematic. 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 175 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. The "Alarm Codes" key does not need to be pressed for shutdown faults.

   5. Check if the CID 175 FMI 2 is not showing. This means that the CID 175 FMI 2 is inactive. Check if the CID 175 FMI 3 is now showing. CID 175 FMI 3 is now active.

      Expected Result: CID 175 FMI 2 is not showing. The fault is inactive. CID 175 FMI 3 is now showing. The fault is active.

      Results:

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

      • NOT OK: The CID 175 FMI 2 fault is 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 175 FMI 2 is no longer showing. Check if the CID 175 FMI 3 is now showing.

      Expected Result: CID 175 FMI 2 is not showing. The fault is inactive. CID 175 FMI 3 is now showing. The fault is 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 175 FMI 2 is still showing. The GSC+ is faulty. Replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace". STOP.