Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Jeep >> 2014 >> Grand Cherokee Laredo, AWD >> Repair and Diagnosis >> Engine Performance >> System >> 3.6L - DTCS P0501 To P1128 >> Diagnosis And Testing >> P0685-ASD/Main Control Circuit >> Diagnostic Test

Diagnostic Test

  1. ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, select View DTCs.

      Is the DTC Active at this time?

      Yes 

      • Go To  2

      No 

  2. ASD RELAY 
    1. With the scan tool, erase DTCs.
    2. Turn the ignition off.
    3. Replace the ASD Relay with a know good relay.
    4. Turn the ignition on.
    5. Using the scan tool, select View DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

  3. CHECK THE (K51) ASD CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Remove the ASD Relay from the PDC.
    3. Disconnect the PCM C1 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. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    5. Measure the resistance of the (K51) ASD Control circuit between the ASD Relay connector in the PDC and the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (K51) ASD Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE (K51) ASD CONTROL CIRCUIT FOR A SHORT TO ANOTHER VOLTAGE SUPPLY CIRCUIT 
    1. Measure the resistance between the (K51) ASD Control circuit and all other circuits at the GPEC Adaptor.

      Is the resistance above 10k Ohms between the (K51) ASD Control circuit and all other circuits?

      Yes 

      • Go To  5

      No 

      • Repair the (K51) ASD Control circuit for short to the circuit that measured below 10k Ohms.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE (K51) ASD CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Measure the resistance between ground and the (K51) ASD Control circuit at the ASD Relay connector in the PDC.

      Is the resistance above 10k Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the (K51) ASD Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related PDC and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the PDC and Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No