P0230

DTC P0230

DTC DESCRIPTOR

DTC P0230
Fuel Pump Relay Control Circuit

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection






CIRCUIT/SYSTEM DESCRIPTION
An electric fuel pump is used to prime the fuel system after changing the fuel filter or servicing the fuel system. The fuel pump is part of the diesel fuel conditioning module (DFCM) assembly. The fuel pump is powered by the fuel pump relay. The fuel pump relay is controlled by the engine control module (ECM). The ECM enables the fuel pump when the ignition is turned on and will continue to run for two minutes or until the engine starts. If the engine does not start due to low fuel pressure and the ignition is left in the ON position; the pump will run for up to two minutes or until the ignition is turned off. The ECM will also turn off the fuel pump if incorrect voltage is detected on the control circuit. The ECM will need to be powered down with a key cycle during diagnosis or after repairs, before it will command the fuel pump on again.

CONDITIONS FOR RUNNING THE DTC
Ignition is ON.

CONDITIONS FOR SETTING THE DTC
- The ECM detects an incorrect voltage on the control circuit of the fuel pump relay.
- The above condition exists for 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION
Install the EN-47620 and J 34730-1A to the fuel system service port on the right front side of the engine. Command the fuel pump on using a scan tool and observe the fuel pressure gauge. Fuel pressure should be a minimum of 69 kPa (10 psi) with the fuel pump running.

CIRCUIT/SYSTEM TESTING
1. Turn OFF the ignition.
2. Remove the fuel pump relay and turn ON the ignition, with the engine OFF.
3. Probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground.
4. Command the fuel pump ON and OFF with a scan tool.
- If the test lamp remains illuminated, test the fuel pump relay control circuit for a short to voltage or a faulty ECM.
- If the test lamp does not turn ON and OFF with each command, test the fuel pump relay control circuit for a short to ground, an open, or a faulty ECM.
5. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the relay.
6. Command the fuel pump ON and OFF with a scan tool.
- If the test lamp does not turn ON and OFF with each command, test the fuel pump relay ground circuit for an open or high resistance.
- If the test lamp turns ON and OFF with each command, replace the fuel pump relay.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Control Module References for ECM replacement, programing, and setup
- Diesel Fuel Conditioning Module Replacement Verification Tests