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Home >> Jeep >> 2018 >> Grand Cherokee Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (3.0L Diesel - DTCS P0403-00 To P061C-00) >> DTC Troubleshooting >> P05F4-00-Exhaust AFTERTREATMENT Power Relay Control Circuit Low >> 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 THE SCR RELAY 2 FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Use a known good relay in place of the SCR Relay 2 in the Power Distribution Center (PDC).
    3. Ignition on, engine not running.
    4. With the scan tool, erase DTCs in the Powertrain Control Module (PCM).
    5. Start the engine and allow it to reach normal operating temperature.
    6. With the scan tool, select View DTCs.

      Does the DTC return?

      Yes 

      • Go To  3

      No 

  3. CHECK THE (K402) SCR RELAY 2 CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Remove the SCR Relay 2.
    3. Disconnect the PCM C1 harness connector.
    4. Measure the resistance between ground and the (K402) SCR Relay 2 Control circuit at the PCM C1 harness connector.

      Is the resistance above 10k Ohms?

      Yes 

      • Go To  5

      No 

      • Go To  4
  4. CHECK THE (K402) SCR RELAY 2 CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Disconnect the PDC C3 harness connector.
    2. Measure the resistance between ground and the (K402) SCR Relay 2 Control circuit at the PCM C1 harness connector.

      Is the resistance above 10k Ohms?

      Yes 

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

      No 

      • Repair the (K402) SCR Relay 2 Control circuit (between the PDC and the PCM) for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  5. 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 .