P0088

P0088-FUEL RAIL PRESSURE TOO HIGH





For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The 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 4 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. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. OTHER DTC'S
With the scan tool, read DTC's.
Are any other injector/fuel pressure related DTC's present?

Yes


- Troubleshoot other injector/fuel pressure related DTC's first.


No


- Go To 2



2. LIFT PUMP
Perform "*IN-TANK FUEL LIFT PUMP FLOW TEST - DIESEL"In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure
Did vehicle pass the *IN-TANK FUEL LIFT PUMP FLOW TEST - DIESEL?

Yes


- Go To 3


No


- Repair the Lift pump.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



3. FUEL CONTROL ACTUATOR
Check for a mechanically stuck Fuel Control Actuator (FCA). Using the scan tool, actuate the fuel control actuator.

NOTE: The fuel control actuator will only click when cycled off.

Do you hear a click from the actuator when you cycle the actuator off with the scan tool?

Yes


- Go To 4


No


- Replace the fuel control actuator.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



4. CHECK VALVE DAMAGED OR BLOCKED
Check the fuel drain line check valve in the rear of the cylinder head for signs of damage, blockage, or debris.

Is the check valve damaged or blocked?

Yes


- Repair the cause of the damaged or blocked check valve or replace the valve.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 5



5. Fuel Pressure Sensor
Using the scan tool, monitor the fuel pressure reading from the fuel rail pressure sensor at idle and at 2000 RPM.
Is the fuel rail pressure reading higher at 2000 RPM than at idle?

Yes


- Repair Complete.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Replace the fuel pressure sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test