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 MANUALSJEEP2014GRAND CHEROKEE LAREDO, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 23 (5.7L - DTCS P000B TO P0298)DIAGNOSIS AND TESTINGP0155-O2 SENSOR 2/1 HEATER PERFORMANCEDIAGNOSTIC TEST

2014 Jeep Grand Cherokee Laredo, AWD

Diagnostic Test

2014 Jeep Grand Cherokee Laredo, AWDSECTION Diagnostic Test

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

O2 SENSOR HEATER OPERATION
1. Turn the ignition off.
  NOTE:
  Wait a minimum of eight 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.
2. Ignition on, engine not running.
3. With the scan tool, actuate the O2 Heater Test.
4. Using the scan tool, monitor O2 Sensor 2/1 voltage for at least two minutes.
  Does the voltage stay above 4.5 volts?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
O2 SENSOR 2/1 HEATER ELEMENT
1. Turn the ignition off.
  NOTE:
  Allow the O2 sensor to cool down to room temperature.
2. Disconnect the 2/1 O2 Sensor harness connector.
3. Measure the resistance of the O2 Sensor Heater Element across the O2 Sensor, between the O2 Heater Control terminal and the O2 Heater ground terminal.
  NOTE:
  O2 Sensor Heater Element resistance values should be measured at 21.1C (70°F). The resistance value will vary with different temperature values.
  
  Is the resistance of the O2 Sensor 2/1 Heater Element between 2.0 and 30.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Verify that there is good pin to terminal contact in the O2 Sensor 2/1 and Powertrain Control Module connectors. If OK, replace the O2 Sensor 2/1. Refer to SENSOR, OXYGEN, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K199) O2 SENSOR 2/1 HEATER CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Disconnect the PCM C2 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 GPEC Diagnostic Adaptor to perform the diagnosis.
2. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
3. Measure the resistance of the (K199) O2 Sensor 2/1 Heater Control circuit from the O2 Sensor 2/1 harness connector to the GPEC Adaptor.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the excessive resistance in the (K199) O2 2/1 Heater Control circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE O2 SENSOR 2/1 HEATER GROUND CIRCUIT OPEN/HIGH RESISTANCE

Fig 1: Checking O2 Sensor Heater Ground Circuit For An Open Or High Resistance
Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between ground and the O2 Heater ground circuit at the O2 Sensor 2/1 harness connector.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the excessive resistance in the O2 Heater ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 2/1 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 2/1 and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

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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.