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Home >> Jeep >> 2024 >> Wagoneer Carbide, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 21 (3.0L - DTCS P0073-00 To P00C1-00) >> DTC Troubleshooting >> P0090-00-Fuel Pressure 1 Control Circuit/Open >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2024 Jeep Grand Wagoneer L and 2024 Jeep Grand Wagoneer. However, it is still accessible from the selected car via links, so may be relevant.
  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, with the scan tool, 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  3

      No 

  2. ISOLATE AND CHECK THE FUEL QUANTITY SOLENOID 1 (N17) HSD CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. The ignition must be off when checking the continuity of a circuit.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  3

      No 

  3. ISOLATE AND CHECK THE FUEL QUANTITY SOLENOID 1 (N18) LSD CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. The ignition must be off when checking the continuity of a circuit.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  4

      No 

  4. ISOLATE AND CHECK THE FUEL QUANTITY SOLENOID 1 (N17) HSD CONTROL CIRCUIT FOR A SHORT TO THE FUEL QUANTITY SOLENOID 1 (N18) LSD CONTROL CIRCUIT 
    1. The ignition must be off when checking for a short between circuits.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Connect the test leads of the DVOM and check for continuity between the circuits being tested at the component harness connector.
      NOTE:

      There should be no continuity between the circuits being tested.

      Is there continuity between the circuits?

      Yes 

      No 

      • Go To  5
  5. REPLACE THE FUEL QUANTITY SOLENOID 1 AND RETEST FOR DTCS 
    1. Turn the ignition off.
    2. Replace the Fuel Quantity Solenoid 1 in accordance with the Service Information. Refer to ASSEMBLY, FUEL PUMP, REMOVAL AND INSTALLATION .
    3. Connect the component and Electronic Control Unit (ECU) harness connectors.
    4. Turn the ignition on.
    5. With the scan tool, erase all DTCs.
    6. Turn the ignition off for a minimum of 10.0 seconds.
    7. Turn the ignition on.
    8. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    9. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  6

      No 

  6. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. 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.

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

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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