C7 and C9 On-Highway Engines 0094-11 Low Cranking Fuel Pressure (63) Caterpillar

Conditions Which Generate This Code:

Note: This diagnostic code represents an event. This diagnostic code does not represent an electronic system fault.

The Engine Control Module (ECM) detects all of the following conditions:

• Engine speed is greater than 0 RPM.

• Engine speed is less than 100 RPM below the engine idle RPM (engine cranking).

• Fuel pressure is less than 175 kPa (25 psi).

The engine must be cranked for more than ten seconds without being started.

System Response:

Factory passwords are required in order to clear this diagnostic code.

Possible Performance Effect:

If the engine coolant temperature is less than 18 °C (64 °F), the injection actuation pressure is limited to 12000 kPa (1750 psi).

Troubleshooting:

This diagnostic code indicates a low fuel pressure in the low pressure fuel system. This diagnostic code does not indicate a problem with the ECM or the fuel pressure sensor.

In a fuel system that is functioning properly, this code is usually generated after a fuel filter has been serviced. This code becomes active if the low pressure fuel system does not achieve the proper pressure. This code will be active only during engine cranking. The code is logged for each occurrence.

Test Step 1. Check the Fuel Level

Check the fuel level.

Expected Result:

The fuel level is OK.

Results:

• OK - The fuel level is OK. Proceed to Test Step 2.

• Not OK - The fuel level is low.

  Repair: Fill the fuel tanks with fuel.

  Verify that the repair eliminates the problem.

  STOP

Test Step 2. Verify Proper Sensor Installation

1. Check the installation of the fuel pressure sensor.

2. Check the wiring of the fuel pressure sensor. Refer to the engine's Electrical Schematic. Ensure that all of the wires and the connectors are properly connected.

Expected Result:

The sensor is properly installed and the wiring is correct.

Results:

• OK - The sensor is properly installed and the wiring is correct. Proceed to Test Step 3.

• Not OK - The sensor is not properly installed and/or the wiring is incorrect.

  Repair: Install the fuel pressure sensor properly. Repair the wiring and/or the connectors.

  Verify that the repair eliminates the problem.

  STOP

Test Step 3. Prime the Low Pressure Fuel System

1. Use the hand priming pump to prime the low pressure fuel system. Refer to the appropriate information in Systems Operation/Testing and Adjusting.

2. Connect the AVSpare Electronic Technician (ET) to the data link connector.

3. Crank the engine. Monitor the status for "Fuel Pressure" during engine cranking.

Expected Result:

"Fuel Pressure" is greater than 175 kPa (25 psi) during engine cranking.

Results:

• OK - The fuel pressure exceeds 175 kPa (25 psi) during engine cranking. Priming the fuel system resolved the problem.

  Repair: If the fuel filter was serviced immediately prior to the activation of this diagnostic code, the fuel system was not properly primed before the engine was cranked.

  Verify that the repair eliminates the problem.

  If the fuel filter had not been serviced prior to the activation of this fault, air may be entering the fuel system. Check the fuel system for air prior to releasing the vehicle. Refer to Systems Operation/Testing and Adjusting for information that is related to checking for air in the fuel system. If necessary, repair the low pressure fuel system.

  Verify that the repair eliminates the problem.

  STOP

• Not OK - The fuel pressure does not exceed 175 kPa (25 psi) during engine cranking. Proceed to Test Step 4.

Test Step 4. Verify the Operation of the Fuel Pressure Sensor

1. Turn the keyswitch to the OFF position.

2. Remove the fuel pressure sensor.

3. Install a 1U-5470 Engine Pressure Group into the low pressure fuel system with a Tee fitting in the port for the fuel pressure sensor.

4. Connect the fuel pressure sensor to the Tee fitting.

5. Monitor the status for "Fuel Pressure" on Cat ET.

6. Crank the engine.

7. Compare the pressure reading on the gauge to the pressure reading on Cat ET.

Expected Result:

The pressure readings are within 35 kPa (5.0 psi) of each other.

Results:

• OK - The sensor is functioning properly.

  Repair: There is a mechanical problem with the low pressure fuel system.

  Repair the low pressure fuel system. Refer to the Systems Operation/Testing and Adjusting for information that is related to repairing the low pressure fuel system.

  Verify that the repair eliminates the problem.

  STOP

• Not OK - The sensor is not functioning properly.

  Repair: Temporarily install a new fuel pressure sensor.

  If the new sensor repairs the problem, reinstall the suspect sensor.

  If the problem returns, replace the sensor.

  Verify that the repair eliminates the problem.

  STOP