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Home >> Jeep >> 2021 >> Cherokee Trailhawk >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> 3.2L - DTCS P0073 To P0298 >> DTC Troubleshooting >> P0140-O2 Sensor 1/2 Signal Inactive >> Diagnostic Test
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Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. Start the engine.
    2. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    3. With the scan tool, read DTCs and record on the repair order.
      NOTE:

      It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

      Is the DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK THE EXHAUST SYSTEM FOR LEAKS 
    1. Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS .

      Were any exhaust leaks found?

      Yes 

      No 

      • Go To  3
  3. CHECK THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT VOLTAGE VALUE 
    1. Turn the ignition off
    2. Disconnect the O2 Sensor 1/2 harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (K141) O2 Sensor 1/2 Signal circuit in the O2 Sensor 1/2 harness connector.

      Is the voltage between 4.1 and 5.0 volts?

      Yes 

      • Go To  4

      No 

  4. CHECK THE (K904) O2 SENSOR 1/2 RETURN CIRCUIT VOLTAGE VALUE 
    1. Measure the voltage on the (K904) O2 Sensor 1/2 Return circuit in the O2 Sensor 1/2 harness connector.

      Is the voltage at 2.5 volts?

      Yes 

      • Go To  5

      No 

  5. CHECK THE O2 SENSOR WIRING AND CONNECTOR 
    NOTE:

    Check for signs of contaminants that may have damaged the O2 Sensor 1/2, such as contaminated fuel, unapproved silicone, oil and coolant.

    1. Using the appropriate SYSTEM WIRING DIAGRAM/schematic as a guide, inspect the wiring and connectors between the O2 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.
    4. Perform any Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No 

      • Replace the Oxygen Sensor 1/2 in accordance with the Service Information. Refer to 3.2L .
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .