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Home >> Jeep >> 2018 >> Grand Cherokee Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 8 (3.0L Diesel - DTCS P0627-00 To P1692-00) >> DTC Troubleshooting >> P068B-00-ECM Power De-Energized Performance - Too Late >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR AN ACTIVE DTC 
    1. Ignition on, engine not running.
    2. With the scan tool, erase DTCs in the Powertrain Control Module (PCM).
    3. Start the engine and allow it to reach normal operating temperature.
    4. With the scan tool, select View DTCs.

      Is the status Active for this DTC?

      Yes 

      • Go To  2

      No 

      • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any other PCM system DTCs active or pending?

      Yes 

      No 

      • Go To  3
  3. CHECK THE ASD RELAY FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Install a known good relay in place of the ASD Relay.
    3. Turn the ignition on.
    4. With the scan tool, erase DTCs.
    5. Perform several ignition key cycles, pausing for at least 40 seconds between each cycle.
    6. Turn the ignition on.
    7. With the scan tool, read ECM DTCs.

      Did this DTC set again?

      Yes 

      • Go To  4

      No 

  4. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Remove the ASD Relay from the PDC.
    3. Disconnect the PCM C1 harness connector.
    4. Measure the resistance between ground and the (K51) ASD Relay Control circuit at the PCM C1 harness connector while wiggling the wiring harness and connectors.

      Does the resistance remain above 10k Ohms while wiggling the wiring harness and connectors?

      Yes 

      • Go To  6

      No 

      • Go To  5
  5. CHECK THE POWER DISTRIBUTION CENTER FOR PROPER OPERATION 
    1. Disconnect the PDC C3 harness connector.
    2. Measure the resistance between ground and the (K51) ASD Relay Control circuit at the PCM C1 harness connector while wiggling the wiring harness and connectors.

      Does the resistance remain above 10k Ohms while wiggling the wiring harness and connectors?

      Yes 

      • Replace the Power Distribution Center in accordance with the service information.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Repair the (K51) ASD Relay Control circuit for a short to ground.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  6. CHECK THE ASD RELAY OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Reconnect the PCM C1 harness connector.
    2. Turn the ignition on.
    3. Measure the voltage on the ASD Relay Output circuit at the ASD Relay Output terminal.

      Is the voltage above 1.0 Volts?

      Yes 

      • Go To  7

      No 

      • Go To  8
  7. CHECK THE POWER DISTRIBUTION CENTER FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Disconnect the PDC C3 harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the ASD Relay Output circuit at the ASD Relay Output terminal.

      Is the voltage above 1.0 Volts?

      Yes 

      • Replace the Power Distribution Center in accordance with the service information.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Refer to the Fuses/Relay-ASD Wiring Diagrams. Determine which of the 3 ASD Relay Output circuits (F342, F343, or F344) is above 1.0 Volts (with the ASD Relay disconnected) and repair that circuit for a short to voltage.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  8. CHECK THE PCM POWER AND GROUND CIRCUITS FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Reconnect the ASD Relay.
    3. Refer to symptom CHECKING THE PCM POWER AND GROUNDS and verify proper Ignition, Battery and Ground circuits at the PCM.

      Were any problem found with the PCM Ignition, Battery or Ground circuits?

      Yes 

      No 

      • Go To  9
  9. 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 

      • Repair the poor connections.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .