P0088

P0088-FUEL RAIL PRESSURE TOO HIGH





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams. Electrical Diagrams

Theory of Operation

The Engine Control Module (ECM) will turn on the MIL lamp immediately after the diagnostic runs and fails. During this time the ETC lamp will also illuminate. The ECM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Engine running.

- Set Condition:
Fuel pressure is above a calibrated value for a calibrated amount of time.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. FUEL LEAKS

NOTE: If there are any other fuel system related DTCs present, repair those DTCs before proceeding.

NOTE: Verify that the fuel level is above 15% using the scan tool.

1. Turn the ignition off.
2. Visually inspect the low and high pressure side of the fuel system for fuel leaks or damaged components.

Do you have any fuel leaks or damaged components?

Yes

- Repair the fuel leak.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. CHECKING FUEL RETURN LOCATIONS FOR BLOCKED LINES
1. Check the following fuel return locations for blocked or restricted return flow:
- Fuel return line from the rear of the cylinder head.
- Fuel return line from the High Pressure Pump.
- Fuel return line from the Pressure Limiting Valve.
- Fuel return line to the Fuel Tank.

Are any of the return lines damaged or blocked?

Yes

- Repair or replace the damaged fuel line.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. FUEL PRESSURE SENSOR
1. Using the scan tool, monitor the fuel pressure reading from the Fuel Pressure Sensor at idle and at 2000 RPM.

Is the fuel rail pressure reading higher at 2000 RPM than at idle?

Yes

- Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Checking the Fuel Delivery System

No

- Replace the Fuel Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.