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Home >> Jeep >> 2018 >> Grand Cherokee Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (3.0L Diesel - DTCS P0001-00 To P01CC-00) >> DTC Troubleshooting >> P0088-00-Fuel Rail Pressure Too High >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECKING FOR OTHER PCM DTCS 
    1. Turn the ignition on.
    2. With the scan tool, read the PCM DTCs.

      Are there any other DTCs present?

      Yes 

      No 

      • Go To  2
  2. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, erase the PCM DTCs.
    3. Test drive the vehicle under various load and speed conditions to attempt to duplicate the fault.
    4. With the scan tool, read the PCM DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

  3. CHECK THE FUEL SYSTEM FOR A LEAK 
    1. Turn the ignition off.
    2. Inspect the entire fuel system for leakage.

      Is there any evidence of leakage?

      Yes 

      • Repair as necessary in accordance with the Service Information.
      • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE FUEL SYSTEM FOR CONTAMINATION 
    1. Inspect the fuel system for contamination.

      Is the fuel contaminated?

      Yes 

      • Repair as necessary in accordance with the Service Information.
      • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE ENGINE FOR PROPER STARTING CONDITIONS 
    1. With the scan tool, erase the PCM DTCs.
    2. Attempt to start the engine.

      Does the engine start and idle?

      Yes 

      • Go To  6

      No 

      • Go To  10
  6. CHECK THE FUEL PRESSURE REGULATOR FOR PROPER PRESSURE 
    1. With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure.
      NOTE:

      A sticking Fuel Pressure Regulator is indicated by the Actual Fuel Pressure gradually dropping below the Fuel Pressure Setpoint then suddenly increasing (spiking) above the Fuel Pressure Setpoint.

      Does the Actual Fuel Pressure gradually decrease then suddenly increase (spike) above the Fuel Pressure Setpoint?

      Yes 

      No 

      • Go To  7
  7. CHECK THE FUEL DELIVERY SYSTEM FOR PROPER OPERATION 
    1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM .

      Were there any problems with the Fuel Delivery System?

      Yes 

      • Repair as necessary in accordance with the Service Information.
      • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. CHECK THE FUEL INJECTOR(S) FOR PROPER OPERATION 
    NOTE:

    An injector that sticks open can cause this DTC. A sticking injector will cause the engine to misfire and emit excessive black smoke from the exhaust system.

    Does the engine exhibit the symptoms described in the above note?

    Yes 

    • Using the service information, remove and inspect the Fuel Injectors for signs of damage or debris that may cause the injector to stick. Sticking injectors may cause the combustion chamber to become black and oil soaked. Replace Injector(s) as necessary.
    • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

    No 

    • Go To  9
  9. CHECK THE FUEL PRESSURE REGULATOR FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Replace the Fuel Pressure Regulator in accordance with the Service Information. Refer to REGULATOR, FUEL PRESSURE, REMOVAL .
    3. Turn the ignition on.
    4. With the scan tool, erase the PCM DTCs.
    5. Attempt to start and test drive the vehicle.
    6. With the scan tool, read the PCM DTCs.

      Did the DTC return?

      Yes 

      No 

  10. CHECK THE FUEL DELIVERY SYSTEM FOR PROPER OPERATION 
    1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM .

      Were there any problems with the Fuel Delivery System?

      Yes 

      • Repair as necessary in accordance with the service information.
      • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  11
  11. CHECK THE FUEL QUANTITY SOLENOID FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Replace the Fuel Quantity Solenoid in accordance with the Service Information. Refer to SOLENOID, FUEL QUANTITY, REMOVAL .
    3. Turn the ignition on.
    4. With the scan tool, erase the PCM DTCs.
    5. Attempt to start and test drive the vehicle.
    6. With the scan tool, read the PCM DTCs.

      Did the DTC return?

      Yes 

      • Go To  12

      No 

  12. CHECK THE FUEL PRESSURE REGULATOR FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Replace the Fuel Pressure Regulator in accordance with the Service Information. Refer to REGULATOR, FUEL PRESSURE, REMOVAL .
    3. Turn the ignition on.
    4. With the scan tool, erase the PCM DTCs.
    5. Attempt to start and test drive the vehicle.
    6. With the scan tool, read the PCM DTCs.

      Did the DTC return?

      Yes 

      No