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Home >> Jeep >> 2022 >> Grand Cherokee Laredo, AWD >> Repair and Diagnosis >> Engine Performance >> System >> 3.6L - DTCS P062C To P0699 >> DTC Troubleshooting >> P0685-ASD/Main Control Circuit >> Diagnostic Test
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Diagnostic Test

  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  2

      No 

  2. ISOLATE AND CHECK THE ASD RELAY (K51) CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE PCM HARNESS CONNECTOR 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
    3. Disconnect the PDC harness connector.
    4. Check for continuity between the ASD Relay (K51) Control circuit and all other circuits at the PDC harness connector.

      Is there continuity between the ASD Relay (K51) Control circuit and any other circuit?

      Yes 

      • Repair the short to the circuit that showed continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  3
  3. CHECK THE ASD RELAY (K51) CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity between ground and the ASD Relay (K51) Control circuit at the PDC harness connector.

      Is there continuity between ground and the ASD Relay (K51) Control circuit?

      Yes 

      • Repair the ASD Relay (K51) Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE ASD RELAY (K51) CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the ASD Relay (K51) Control circuit between the PDC C2 harness connector and the PCM C2 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the ASD Relay (K51) Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE ASD RELAY AND PDC FOR PROPER OPERATION 
    1. Reconnect the PCM C2 harness connector.
    2. Reconnect the PDC harness connector.
    3. Turn the ignition on.
      NOTE:

      This step is intended to determine if the relay coil can be energized.

    4. Using a 12-volt test light connected to ground, back probe the PDC Relay (K51) Control circuit at the PDC C2 connector.
      NOTE:

      The relay should make an audible click when closing.

      NOTE:

      Using a 12-volt test light connected to ground, probe the PDC Relay (F342) Output circuit at the PDC C2 connector to verify the relay is closing when energized. If the relay is operating correctly, the test light should illuminate brightly.

      Does the PDC Relay close when the control circuit is grounded?

      Yes 

      • Go To  6

      No 

      • Check all fuses in the PDC. If a fuse is open, replace the fuse and retest. If no problems are found with the fuses, replace the Power Distribution Center (PDC) in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. 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. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect 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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