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Home >> Jeep >> 2018 >> Grand Cherokee Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (3.0L Diesel - DTCS P0001-00 To P01CC-00) >> DTC Troubleshooting >> P0030-00-O2 Sensor 1/1 Heater Circuit >> 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 PCM.
    3. Start the engine and allow the engine to reach normal operating temperature.
    4. Monitor the scan tool for at least two minutes.
    5. With the scan tool, read DTCs and record on the repair order.

      Is the DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    GC0143281Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the Oxygen Sensor harness connector.
    3. Disconnect the PCM C1 harness connector.
    4. Measure the resistance of the (K79) O2 Sensor 1/1 Heater Control circuit between the Oxygen Sensor harness connector and the PCM C1 harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the (K79) O2 Sensor 1/1 Heater Control circuit for an open or high resistance.
      • Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  3. CHECK THE OXYGEN SENSOR FOR PROPER OPERATION 
    1. Reconnect the PCM C1 harness connector.
    2. Replace the Oxygen Sensor in accordance with the Service Information. Refer to SENSOR, OXYGEN, REMOVAL .
    3. Start the engine.
    4. Allow the engine to reach normal operating temperature.
    5. Monitor the scan tool for at least two minutes.
    6. With the scan tool, select View DTCs.

      Is the status Active for this DTC?

      Yes 

      • Go To  4

      No 

  4. 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