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Home >> Jeep >> 2021 >> Cherokee Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 3.2L - DTCS P0300 To P054A >> DTC Troubleshooting >> P0521-Engine Oil Pressure Sensor Performance >> Diagnostic Test
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Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    2. With the scan tool, read DTCs and record on the repair order.

      Is the DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK THE ENGINE MECHANICAL AND LUBRICATION FOR PROPER TOLERANCES AND CONDITION 
    NOTE:

    The following items should be considered before determining the cause of this DTC. Failure to do so may lead to misdiagnosis.

    • ENGINE MECHANICAL TOLERANCES OUT OF SPECIFICATION
    • ENGINE OIL PRESSURE OUT OF SPECIFICATION
    • LOW ENGINE OIL
    • DETERIORATED OR DIRTY OIL
    • ENGINE OIL CONTAMINATED (i.e., coolant and/or fuel)

    1. If any of the above conditions are found, repair as necessary.

      Were any of the above conditions present?

      Yes 

      No 

      • Go To  3
  3. CHECK THE ENGINE OIL PRESSURE (EOP) SENSOR FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Disconnect the EOP Sensor harness connector.
    3. Turn the ignition on.
    4. With the scan tool, monitor the EOP Sensor voltage.
    5. Connect a jumper between the (K900) Sensor Ground circuit and the (G6) EOP Signal circuit.
      NOTE:

      Engine Oil Pressure voltage should change from approximately 4.9 volts to less than 0.1 volt.

      Is the voltage reading within the listed specification when the jumper is installed?

      Yes 

      • Verify that there is good pin to terminal contact in the Sensor and Powertrain Control Module connectors. Remove the Engine Oil Pressure (EOP) Sensor and ensure the oil passage/port is free from any blockage. If no problem is found, replace the EOP Sensor. Refer to SENSOR, OIL PRESSURE, REMOVAL .
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
        NOTE:

        Remove the jumper before continuing.

  4. CHECK THE (G6) EOP SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    4. Measure the resistance of the (G6) EOP Signal circuit from the Engine Oil Pressure Sensor harness connector to the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the (G6) EOP Signal circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE (F855) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (F855) 5-Volt Supply circuit from the EOP Sensor harness connector to the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the (F855) 5-Volt Supply circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (K900) Sensor Ground circuit from the EOP Sensor harness connector to the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the (K900) Sensor Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK RELATED HARNESS 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 

      No 

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