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)P0137-O2 SENSOR 1/2 CIRCUIT LOWDIAGNOSTIC 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
1. Turn the ignition on.
2. With a scan tool, select View DTCs. Record DTC and Freeze Frame information.
3. 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.
4. 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 .
(K141) O2 1/2 SIGNAL CIRCUIT
1. Turn the ignition off.
2. Disconnect the 1/2 O2 Sensor harness connector.
3. Ignition on, engine not running.
4. With a scan tool, monitor the 1/2 O2 Sensor voltage.
  Is the O2 Sensor voltage between 4.1 and 5.0 volts?
  
  Yes
  - Go to step 3
  No
  - Go to step 5
O2 SENSOR

Fig 1: 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 O2 Sensor harness connector.
  Is the voltage at 2.5 volts?
  
  Yes
  - Verify that there is good pin to terminal contact in the 1/2 O2 Sensor and Powertrain Control Module connectors. If OK, replace the 1/2 O2 Sensor.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 4
(K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO GROUND

Fig 2: Measuring Resistance Between Ground And O2 Sensor Return Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the C2 PCM harness connector.
3. Measure the resistance between ground and the (K904) O2 Return Downstream circuit in the O2 Sensor harness connector.
  Is the resistance below 100 ohms?
  
  Yes
  - Repair the short to ground 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 8
(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO GROUND

Fig 3: Measuring Resistance Between Ground And 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. Measure the resistance between ground and the (K141) O2 1/2 Signal circuit in the O2 Sensor harness connector.
  Is the resistance below 100 ohms?
  
  Yes
  - Repair the short to ground in the (K141) O2 1/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 6
(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 RETURN DOWNSTREAM CIRCUIT

Fig 4: Measuring Resistance Between O2 Sensor Signal Circuit And O2 Sensor Return Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (K141) O2 1/2 Signal circuit and the (K904) O2 Return Downstream circuit in the O2 Sensor harness connector.
  Is the resistance below 100 ohms?
  
  Yes
  - Repair the short between the (K904) O2 Return Downstream circuit and the (K141) O2 1/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 7
(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO THE (Z42) O2 1/2 HEATER GROUND CIRCUIT

Fig 5: Measuring Resistance Between O2 Sensor Signal Circuit And O2 Sensor Heater Ground Circuit In O2 Sensor Harness Connector
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (K141) O2 1/2 Signal circuit and the (Z42) O2 1/2 Heater ground circuit in the O2 Sensor harness connector.
  Is the resistance below 100 ohms?
  
  Yes
  - Repair the short between the (Z42) O2 1/2 Heater ground circuit and the (K141) O2 1/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 8
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 1/2 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 O2 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.