100-200 kW Tactical Quiet Generators (TQG) EMCP2 Plus Caterpillar

Illustration 1	g00527056
System Schematic For Engine Oil Pressure Sensor

This diagnostic code is for the pressure sensor (engine oil).

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

The sensor is powered by an 8 volt sensor supply from the GSC+. The oil pressure signal is a pulse width modulated signal. The base frequency of the signal is 500 ± 150 Hz. As pressure changes, the duty cycle of the signal varies from 10 to 95 percent.

• 0 kPa (0 psi) is approximately a duty cycle of 13%. The voltage will be approximately 1.0 DCV.

• 690 kPa (100 psi) is approximately a duty cycle of 85% .

System Response:

Note: The GSC+ is usually programmed to treat a problem with the oil pressure sensor as an alarm fault. The factory default for P004 is 0. If the GSC+ is programmed to shutdown for a problem with the oil pressure sensor, then it is not necessary to press the alarm codes key in order to view the CID 0100 FMI 03. P004 is equal to 1 for a shutdown fault. The CID 0100 FMI 03 is automatically shown on the upper display.

The possible causes of a CID 0100 FMI 03 are listed below:

• The sensor signal is shorted to +battery.

• The sensor signal is open.

Begin performing these procedures only when CID 0100 FMI 03 is showing and the "DIAG" indicator is FLASHING on the upper display. The diagnostic code is active. The GSC+ treats a CID 0100 FMI 03 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 NOT be in the OFF/RESET position. For an inactive diagnostic code, the problem may be intermittent. Use Illustration 1 in order to troubleshoot an inactive diagnostic code. Also see Testing And Adjusting, "Electrical Connector - Inspect". Clear the diagnostic code from the fault log after troubleshooting is complete.

Note: If a CID 0269 for the sensor supply is active, correct the diagnostic code before performing this procedure.

Test Step 1. CHECK THE SUPPLY CIRCUIT.

1. Turn the ECS to the OFF/RESET position and then turn the ECS to the STOP position.

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

3. At the engine harness side of the connector, measure the DC voltage that is between contact "A" and contact "B". Contact "A" is the supply. Contact "B" is the sensor ground.

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 or the engine harness has an open circuit. Proceed to Test Step 5.

Test Step 2. CHECK FOR A DIAGNOSTIC CODE.

1. Check the upper display for a diagnostic code for the sensor supply (CID 0269).

Expected Result:

CID 0269 is not showing on the upper display.

Results:

• OK - CID 0269 is not showing on the upper display. The engine harness has an open circuit. Proceed to Test Step 3.

• NOT OK - CID 0269 is showing on the upper display.

  Repair: There is a problem with the sensor supply. Exit this procedure and troubleshoot the sensor supply (CID 0269).

  STOP

Test Step 3. CHECK THE SIGNAL CIRCUIT.

Note: The ECS remains in the STOP position and the sensor remains disconnected from the engine harness.

1. At the engine harness side of the sensor connector, measure the voltage (DCV) between contact "C" and contact "B". Contact "C" is the signal. 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. Reconnect the sensor. Turn the ECS to OFF/RESET and then turn the ECS to STOP. If the CID 0100 FMI 03 fault is still showing on the upper display, the sensor has failed. Replace the sensor.

  STOP

• BATTERY VOLTAGE - The voltage is equal to +battery.

  Repair: The engine harness has failed. The signal circuit within the engine harness is shorted to +battery. Troubleshoot the engine harness and repair the engine harness.

  STOP

• NOT 7.0 ± 0.5 OR +BATTERY - The voltage is NOT 7.0 ± 0.5 DCV and the voltage is NOT equal to +battery voltage. The GSC+ or the harness has failed. Proceed to Test Step 4.

Test Step 4. CHECK THE HARNESS FOR A SHORT.

Note: See Illustration 1 when this step is performed. The sensor remains disconnected from the engine harness.

1. Turn the ECS to OFF/RESET.

2. Disconnect the harness connector from the GSC+.

3. At the GSC+ harness connector, measure the resistance from signal contact "8" to all other contacts of the connector.

Expected Result:

The resistance should be greater than 5000 ohms for each measurement.

Results:

• OK - The resistance is greater than 5000 ohms for each measurement. The harness functions properly. Proceed to Test Step 5.

• NOT OK - The resistance is not greater than 5000 ohms for each measurement.

  Repair: Troubleshoot the harness and repair the harness between the sensor connector and the connector of the GSC+ .

  STOP

Test Step 5. CHECK THE HARNESS FOR AN OPEN.

Note: See Illustration 1 when you are performing this step. 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.

1. Measure the resistance of the ground circuit. Measure the resistance from contact "B" of the harness connector for the sensor to contact "31" of the harness connector for the GSC+.

2. Measure the resistance of the signal circuit. Measure the resistance from contact "C" of the harness connector for the sensor to contact "8" of the harness connector for the GSC+.

3. Measure the resistance of the sensor supply circuit. The sensor supply circuit is 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 - The resistance is 5 ohms or less. Proceed to Test Step 6.

• NOT OK - 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 6. CHECK THE ELECTRICAL CONNECTORS.

1. Check the electrical connectors, terminals and wiring. Refer to Testing And Adjusting, "Electrical Connector - Inspect".

Expected Result:

All connectors, terminals and wiring should function properly.

Results:

• OK - All connectors, terminals and wiring should function properly.

  Repair: Connect all harness connectors that were previously disconnected. Start the engine. If the CID 0100 FMI 03 is still showing, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".

  STOP

• NOT OK - There is a problem with a connector, a terminal or wiring.

  Repair: Repair the component that has failed.

  STOP