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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 >> P067B-00-Cylinder 4 Glow Plug Circuit High >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR ACTIVE DTC 
    1. Ignition on, engine not running.
    2. With the scan tool, erase DTCs in the Powertrain Control Module (PCM).
    3. Perform several ignition cycles leaving the ignition on for at least 10 seconds then off for 10 seconds.
    4. With the scan tool, read the PCM DTCs.

      Did this DTC return?

      Yes 

      • Go To  2

      No 

      • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
  2. CHECK THE (A208) GLOW PLUG 4 CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the Glow Plug 4 harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (A208) Glow Plug 4 Control circuit at the Glow Plug 4 harness connector.

      Is there voltage present?

      Yes 

      • Repair the (A208) Glow Plug 4 Control circuit for a short to voltage.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Go To  3
  3. GLOW PLUG 4 
    1. Turn the ignition off.
    2. Replace the Glow Plug in accordance with the service information.
    3. Turn the ignition on.
    4. With the scan tool, erase PCM DTCs.
    5. Perform several ignition key cycles leaving the ignition on for at least 10 seconds per cycle.
    6. With the scan tool, read PCM DTCs.

      Does the scan tool display this DTC?

      Yes 

      • Go To  4

      No 

  4. GLOW PLUG MODULE 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Glow Plug and the Glow Plug Module.
    2. Look for any chafed, pierced, pinched, or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals.
    4. Perform any Technical Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No 

      • Replace the Glow Plug Module in accordance with the service information.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .