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Home >> Jeep >> 2022 >> Gladiator Mojave, Part Time T/Case Control, Standard Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (3.0L Diesel - DTCS P0087-00 To P0116-00) >> DTC Troubleshooting >> P0090-00-Fuel Pressure 1 Control Circuit/Open >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. For future reference, run and save a vehicle Scan Report and all related recorded data.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

      • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
  2. CHECK THE FUEL PRESSURE REGULATOR (K646) CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the Fuel Pressure Regulator harness connector.
    3. Disconnect the PCM C2 harness connector.
    4. Measure the resistance of the Fuel Pressure Regulator (K646) Control circuit between the Fuel Pressure Regulator harness connector and the PCM C2 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the Fuel Pressure Regulator (K646) Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to 3.0L, POWERTRAIN VERIFICATION TEST .
  3. CHECK THE FUEL PRESSURE REGULATOR (K369) RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the Fuel Pressure Regulator (K369) Return circuit between the Fuel Pressure Regulator harness connector and the PCM C2 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the Fuel Pressure Regulator (K369) Return circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to 3.0L, POWERTRAIN VERIFICATION TEST .
  4. CHECK THE ABILITY OF THE PCM TO MONITOR THE FUEL PRESSURE REGULATOR OPERATION 
    1. Reconnect the Fuel Pressure Regulator harness connector.
    2. Reconnect the Powertrain Control Module C2 harness connector.
    3. Turn the ignition on.
    4. With the scan tool, erase DTCs.
    5. Turn the ignition off.
    6. Disconnect the Fuel Pressure Regulator harness connector.
    7. Connect a jumper between the Fuel Pressure Regulator (K646) Control circuit and ground.
    8. Turn the ignition on.
    9. With the scan tool, read DTCs.
      NOTE:

      The scan tool should display a P0091-FUEL PRESSURE CONTROL CIRCUIT LOW DTC with the jumper in place.

      Did the scan tool display as described above?

      Yes 

      No 

      • Go To  5
  5. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Disconnect all PCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    10. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to 3.0L, POWERTRAIN VERIFICATION TEST .

      No 

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