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Home >> Jeep >> 2020 >> Grand Cherokee Trackhawk >> Repair and Diagnosis >> Engine Performance >> System >> 6.2L - DTCS P0300 To P05DA >> DTC Troubleshooting >> P05D8-PCV Regulator Valve Control Circuit/Open >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR ANY SERVICE BULLETINS OR PCM SOFTWARE UPDATES 
    1. Check for any applicable Service Bulletins or Flash updates related to the DTC.

      Are there any applicable Service Bulletins or Flash updates?

      Yes 

      No 

      • Go To  2
  2. 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  3

      No 

  3. CHECK THE MAKEUP AIR SOLENOID CONNECTOR AND TERMINALS 
    1. Turn the ignition off.
    2. Check the Makeup Air Solenoid harness connector for proper connection at the Makeup Air Solenoid.
    3. Verify that the connector is completely plugged in and properly locked prior to disconnecting.
    4. Disconnect the Makeup Air Solenoid harness connector and check for any pushed out, damaged or spread terminals.

      Were any issues found with the connector or terminals?

      Yes 

      • Repair the damaged terminal or properly connect and lock the Makeup Air Solenoid harness connector and retest for DTCs.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE MAKEUP AIR SOLENOID (K710) CONTROL CIRCUIT AND (Z903) GROUND CIRCUIT BY LOAD TESTING THE CIRCUITS AT THE MAKEUP AIR SOLENOID HARNESS CONNECTOR 
    NOTE:

    Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

    NOTE:

    A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

    1. Turn the ignition off.
    2. Disconnect the Makeup Air Solenoid harness connector.
    3. 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.

    4. If it is necessary to probe a terminal at a PCM harness connector, connect the

      (special tool #10436, Adapter, GPEC Diagnostic)

      to the appropriate PCM harness connector.

      NOTE:

      The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

    5. Connect one lead of a load test tool to the Makeup Air Solenoid (K710) Control circuit and the other lead to the (Z903) Ground circuit at the Makeup Air Solenoid harness connector.
    6. Load test the circuit by connecting a fused jumper between Battery (+) and the Makeup Air Solenoid (K710) Control circuit at the GPEC Adaptor.
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  6

      No 

      • Go To  5
  5. DETERMINE IF THE OPEN OR HIGH RESISTANCE IS IN THE MAKEUP AIR SOLENOID (K710) CONTROL CIRCUIT BY LOAD TESTING THE CIRCUIT AT THE MAKEUP AIR SOLENOID HARNESS CONNECTOR 
    1. Disconnect the lead of the load test tool that is connected to the (Z903) Ground circuit at the Makeup Air Solenoid harness connector.
    2. Connect the lead to a good chassis ground to determine if the open or high resistance is in the Makeup Air Solenoid (K710) Control circuit.

      Is the load test bulb illuminated and bright?

      Yes 

      • Repair the (Z903) Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Repair the Makeup Air Solenoid (K710) Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. REPLACE THE MAKEUP AIR SOLENOID AND RETEST FOR DTCS 
    1. Turn the ignition off.
    2. Replace the Makeup Air Solenoid in accordance with the Service Information.
    3. Connect all disconnected 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  7

      No 

      • Replacing the faulty Makeup Air Solenoid repaired the fault.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. 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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