Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSJEEP2009GRAND CHEROKEE LAREDO, 3.0 M, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 9 (DTCS P0125 TO P0196 - GAS)P0158-O2 SENSOR 2/2 CIRCUIT HIGHDIAGNOSTIC TEST

2009 Jeep Grand Cherokee Laredo, 3.0 M, AWD

Diagnostic Test

2009 Jeep Grand Cherokee Laredo, 3.0 M, AWDSECTION Diagnostic Test

WARNING: This page is about a different variant/trim than selected.

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 DTC Active at this time?
  
  Yes
  - Go to step 2
  No
  - Refer to the INTERMITTENT CONDITION Diagnostic Procedure. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K243) O2 2/2 SIGNAL CIRCUIT SHORTED TO VOLTAGE

Fig 1: Measuring Voltage Of O2 Sensor Signal Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C1 and C2 PCM harness connectors.
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
  - Repair the short to voltage in the (K243) O2 Sensor 2/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
  No
  - Go to step 3
(K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO VOLTAGE

Fig 2: Measuring Voltage On O2 Sensor Return Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER 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
  - Repair the short to voltage in the (K904) O2 Return Downstream circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
  No
  - Go to step 4
O2 SENSOR

Fig 3: O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Connect the C1 and C2 PCM harness connectors.
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 2/2 Oxygen Sensor and Powertrain Control Module connectors. If OK, replace the 2/2 O2 Sensor.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 5
    NOTE: Remove the jumper wire before continuing.
(K243) O2 2/2 SIGNAL CIRCUIT OPEN

Fig 4: Measuring Resistance Of O2 sensor Signal Circuit From O2 Sensor Harness Connector To Appropriate Terminal Of PCM Pinout Box 8815
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C1 and C2 PCM harness connectors.
  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 PCM Pinout Box 8815 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 special tool #8815.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Go to step 6
  No
  - Repair the open in the (K243) O2 2/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K904) O2 RETURN DOWNSTREAM CIRCUIT OPEN

Fig 5: Measuring Resistance Of O2 Sensor Return Circuit From O2 Sensor Harness Connector To Appropriate Terminal Of PCM Pinout Box 8815
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (K904) O2 Return Downstream circuit from the O2 Sensor harness connector to the appropriate terminal of special tool #8815.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Go to step 7
  No
  - Repair the open in the (K904) O2 Return Downstream circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
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. Refer to any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Replace and program the Powertrain Control Module per Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.