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Home >> Jeep >> 2012 >> Liberty Limited, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> 3.7L - DTCS P0016 To P0205 >> Diagnosis And Testing >> P0158-O2 Sensor 2/2 Circuit High >> Diagnostic Test
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Diagnostic Test

  1. ACTIVE DTC 
    NOTE:

    If an O2 sensor signal circuit is shorted to voltage, all O2 sensor voltage readings displayed on the scan tool will be approximately 5.0 volts. Diagnose the sensor that set the most current DTC.

    1. Start the engine and allow it to idle for at least 60 seconds.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    2. With a scan tool, select View DTCs.

      Is the status Active for this DTC?

      Yes 

      • Go To  2.

      No 

  2. (K243) O2 2/2 SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 1: Checking O2 Sensor Signal Circuit For Short To Voltage
    GC0090690Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the C1 PCM harness connector.
    3. Disconnect the 2/2 O2 Sensor harness connector.
    4. Turn the ignition on.
    5. Measure the voltage on the (K243) O2 Sensor 2/2 Signal circuit in the O2 Sensor harness connector.
      NOTE:

      Measure the voltage in reference to ground, not the (K904) O2 Return Downstream circuit.

      Is there any voltage present?

      Yes 

      No 

      • Go To  3.
  3. (K904) O2 RETURN DOWNSTREAM CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 2: Checking Oxygen Sensor Return Upstream Circuit For Short To Voltage
    GC0090691Courtesy of CHRYSLER GROUP, LLC
    1. Measure the voltage on the (K904) O2 Return Downstream circuit in the 2/2 O2 Sensor harness connector.

      Is there any voltage present?

      Yes 

      No 

      • Go To  4.
  4. O2 SENSOR 
    Fig 3: O2 Sensor Harness Connector End View
    GC0090692Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Connect the C1 PCM harness connector.
    3. Ignition on, engine not running.
    4. With a scan tool, monitor the 2/2 O2 Sensor voltage.
    5. Connect a jumper wire between the (K243) O2 2/2 Signal circuit and the (K904) O2 Return Downstream circuit in the 2/2 O2 Sensor harness connector.

      Is the voltage between 2.3 and 2.7 volts with the jumper wire installed?

      Yes 

      • Verify that there is good pin to terminal contact in the Oxygen Sensor and Powertrain Control Module connectors. If OK, replace the 2/2 O2 Sensor.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to 3.7L - POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5.
        NOTE:

        Remove the jumper wire before continuing.

  5. (K243) O2 2/2 SIGNAL CIRCUIT FOR AN OPEN 
    Fig 4: Checking O2 Sensor 2/2 Signal Circuit For An Open
    GC0090700Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the C1 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 the PCM Pinout Box (special tool #8815A, Kit, NGC, 38 Position) to perform diagnosis.

    3. Measure the resistance of the (K243) O2 2/2 Signal circuit from the O2 Sensor harness connector to the appropriate terminal of PCM Pinout Box (special tool #8815A, Kit, NGC, 38 Position).

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  6.

      No 

  6. (K904) O2 RETURN DOWNSTREAM CIRCUIT FOR AN OPEN 
    Fig 5: Checking O2 Sensor Return Downstream Circuit For An Open
    GC0090698Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance of the (K904) O2 Return Downstream circuit from the O2 Sensor harness connector to the appropriate terminal of PCM Pinout Box (special tool #8815A, Kit, NGC, 38 Position).

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  7.

      No 

  7. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 2/2 and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched, or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Oxygen Sensor and Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No 

      • Replace and program the Powertrain Control Module in accordance with the service information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to 3.7L - POWERTRAIN VERIFICATION TEST .