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Home >> Jeep >> 2007 >> Commander Overland, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0123 To P0174 >> P0135-O2 Sensor 1/1 Heater Performance >> Diagnostic Test
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Diagnostic Test

  1. 1) O2 SENSOR HEATER OPERATION 

    Turn the ignition off.

    NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize between 4.6 and 5.0 volts.

    Ignition on, engine not running.

    With a scan tool, actuate the 1/1 O2 Heater Test.

    With the scan tool, monitor 1/1 O2 Sensor voltage for at least 2 minutes.

    Does the voltage stay above 4.5 volts? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.
  2. 2) O2 SENSOR HEATER ELEMENT 

    Turn the ignition off.

    NOTE: Allow the O2 sensor to cool down to room temperature.

    Disconnect the O2 Sensor harness connector.

    Measure the resistance of the O2 Heater Element across the 1/1 O2 Sensor connector between the O2 Heater Control terminal and the Heater ground terminal.

    NOTE: O2 Heater Element resistance values should be measured at 21.1° C (70° F). The resistance value will vary with different temperature values.

    Is the resistance of the O2 Sensor Heater Element between 2.0 and 30.0 ohms? 

    Yes 

    1. Go to  3).

    No 

    1. Verify that there is good pin to terminal contact in the Sensor and Control Module connectors. If OK, replace the O2 Sensor.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. 3) (K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN 
    Fig 1: Measuring Resistance Of O2 1/1 Heater Control Circuit
    GC0058506Courtesy of CHRYSLER LLC

    Disconnect the C2 PCM 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 Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (K99) O2 1/1 Heater Control circuit from the O2 harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 0.5 of an ohm? 

    Yes 

    1. Go to  4).

    No 

    1. Repair the excessive resistance in the (K99) O2 1/1 Heater Control circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  4. 4) (Z42) O2 1/1 HEATER GROUND CIRCUIT OPEN 
    Fig 2: Measuring Resistance Between Ground And O2 Heater Ground Circuit
    GC0058508Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (Z42) O2 1/1 Heater ground circuit in the O2 Sensor harness connector.

    Is the resistance below 0.5 of an ohm? 

    Yes 

    1. Go to  5).

    No 

    1. Repair the excessive resistance in the (Z42) O2 1/1 Heater ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  5. 5) POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 1/1 and the Powertrain Control Module (PCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Sensor and Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace and program the Powertrain Control Module per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .
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