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  • P0087 - Fuel Rail Pressure Too Low

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    P0087 - Fuel Rail Pressure Too Low

     Special Tools: Click to display a list of tools used in this procedure

    When Monitored and Set Conditions

    When Monitored: This diagnostic runs continuously when the following conditions are met:
    • With the engine running.

    Set Conditions:
    • The Powertrain Control Module (PCM) detects that the actual fuel pressure reading is below a calibrated threshold. This DTC will cause active regeneration to be disabled.

    Default Actions:
    • The MIL is illuminated.

    Possible Causes

    P000F PRESENT
    EXTERNAL FUEL LEAKS
    GELLED FUEL
    NO VOLTAGE AT CHASSIS MOUNTED FUEL HEATER
    NO VOLTAGE AT ENGINE MOUNTED FUEL HEATER
    CHASSIS MOUNTED FUEL HEATER-FUEL FILTER
    ENGINE MOUNTED FUEL HEATER-FUEL FILTER
    HIGH PRESSURE PUMP
    INJECTOR LEAKAGE
    IN TANK LIFT PUMP
    FUEL PRESSURE LIMITING VALVE

     

    Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTCBased Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

     

    1. P000F PRESENT

     

    1. Ignition on, engine not running.
    2. With the scan tool, read DTCs.
    Is DTC P000F active?

     

    Yes
    • Perform the Diagnostics for DTC P000F first.
    • If DTC P0087 is still active or pending after the P000F Diagnostics is completed, begin this Diagnostic Tree again.

     

    No
    • Go To 2

     

    2. CHECK FOR OTHER DTCS
    1. With the scan tool, read DTCs.
    Are any other injector/fuel pressure related DTCs present?

     

    Yes
    • Troubleshoot other injector/fuel pressure related DTCs first.

     

    No
    • Go To 3

     

    3. CHECK FOR EXTERNAL FUEL LEAKS

     

    1. Put on personal protective equipment.
    2. Operate engine at idle when looking for fuel leaks.
    3. Use the scan tool to operate engine at a variety of engine speeds.
    Any external leaks detected?

     

    Yes
    • Repair or replace component with external fuel leak.
    • Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

     

    No

    • Go To 4

     

    4. CHECK OPERATING CONDITIONS
    1. Determine the environmental conditions at or near the time the DTC set.
    Has the vehicle been operated or cold soaked in ambient temperatures below freezing?

     

    Yes
    • Go To 5

     

    No
    • Go To 7

     

    5. CHECK FOR GELLED FUEL/PERFORM THE IN-TANK LIFT PUMP FLOW TEST

     

    NOTE: Before performing the IN-TANK FUEL LIFT PUMP FLOW test, verify that the fuel level in the fuel tank is above 1/4 full. If fuel tank is not above 1/4 full the pump will take in air causing the test results to be inaccurate.

     

    1. Disconnect the low pressure fuel supply line from the High Pressure Fuel Pump. Connect the Decay Tool,
    Fuel 8978A to the low pressure fuel supply line.

     

    WARNING: To reduce the risk of fire and serious possible serious or fatal injury, place the Reservoir Assembly 534960 (3) on the floor and out of the way so that it is not a trip hazard.

     

    2. Perform the following to purge air from the system:
    • With the scan tool, actuate the In-Tank Fuel Lift Pump Module.
    • Open the Flow Test Valve and allow the fuel to flow into the Reservoir for 10 seconds, then close the Flow Test Valve.
    • Turn the ignition off.
    • Disconnect, empty, and then reconnect the Reservoir Assembly.
    3. Perform the following three times to find the average flow rate:
    • With the scan tool, actuate the In-Tank Fuel Lift Pump Module.
    • Open the Flow Test Valve (1) for 10 seconds, then close the Valve.
    • Turn the ignition off.
    • Measure and record the amount of fuel in the Reservoir Assembly.
    • Disconnect, empty, and then reconnect the Reservoir Assembly.
    4. Add the three recorded measurements and then divide the total by three to calculate the average flow rate. 

    NOTE: The flow rate specification is 500 ml in 10 seconds.

    Does the average flow rate meet or exceed the specification?

     

    Yes
    • If the vehicle exhibited symptoms related to fuel gelling such as hard start, start and stall, and/or low power, but no longer exhibits these symptoms, fuel gelling may have been present but corrected itself. The fuel temperature may have increased through normal operation or if the vehicle was parked inside a warm building. Verify both fuel heaters are receiving power with the ignition on, and also check for proper operation of the fuel heaters. (Refer to 14 - Fuel System/Fuel Delivery, 6.7L Diesel/HEATER, Fuel/Diagnosis and Testing) .
    • Then, Go To 7

     

    No
    • Leave the Fuel Decay Tester installed. Remove both fuel filters and inspect for fuel gelling/wax build-up and other contaminants. If wax build-up is found, the fuel has gelled. Replace both fuel filters and correct the fuel gelling accordingly before any further testing. Verify both fuel heaters are receiving power with the ignition on, and also check for proper operation of the fuel heaters. (Refer to 14 - Fuel System/Fuel Delivery, 6.7L Diesel/HEATER, Fuel/Diagnosis and Testing) .
    • If no wax build-up or signs of fuel gelling is found, replace both Fuel Filter/Water Separators in accordance with the Service Information.
    • Then, Go To 6

     

    6. RECHECK IN-TANK FUEL LIFT PUMP FLOW
    1. Perform the following to purge air from the system:
    • With the scan tool, actuate the In-Tank Fuel Lift Pump Module.
    • Open the Flow Test Valve for 10 seconds, then close the Valve.
    • Turn the ignition off.
    • Disconnect, empty, and then reconnect the Reservoir Assembly.
    2. Perform the following three times to find the average flow rate:
    • With the scan tool, actuate the In-Tank Fuel Lift Pump Module.
    • Open the Flow Test Valve for 10 seconds, then close the valve.
    • Turn the ignition off.
    • Measure and record the amount of fuel in the Reservoir Assembly.
    • Disconnect, empty, and then reconnect the Reservoir Assembly.
    3. Add the three recorded measurements and then divide the total by three to calculate the average flow rate.
    NOTE: The flow rate specification is 500 ml in 10 seconds.

    Does the average flow rate meet or exceed the specification?

     

    Yes

    • Repair complete.
    • Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

     

    No
    • Use the wiring diagram as a guide to check the In-Tank Fuel Lift Pump wiring for an open, high resistance, or short to ground. If the In-Tank Fuel Lift Pump wiring is okay, remove the fuel tank and replace the In-Tank Fuel Lift Pump Module in accordance with the Service Information.
    • Perform the POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

     

    7. CHECK THE FUEL DELIVERY SYSTEM
    1. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) and perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure.
    Were any problems found?

     

    Yes
    • Repair as necessary.

     

    No
    • Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


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