Diagnostic Test

2009 Jeep Compass Limited, ED3, AWD, Automatic CVTSECTION Diagnostic Test
  1. OXYGEN SENSOR 1/2 VOLTAGE 
    1. Start the engine and allow it to reach normal operating temperature.
      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, monitor the 1/2 O2 Sensor Volts.

      Is the voltage less than 2.52 volts?

      Yes 

      • Go to step  2

      No 

  2. (K141) O2 1/2 SIGNAL CIRCUIT VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the Oxygen Sensor 1/2 harness connector.
    3. Turn the ignition on.
    4. With a scan tool, monitor the 1/2 O2 Sensor Volts.

      Is the voltage above 4.8 volts?

      Yes 

      • Go to step  3

      No 

      • Go to step  5
  3. OXYGEN SENSOR 1/2 
    Fig 1: Checking O2 Sensor Circuit
    GC0099793Courtesy of CHRYSLER LLC
    1. Measure the voltage on the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 harness connector.

      Is the voltage between 2.475 and 2.525 volts?

      Yes 

      No 

      • Go to step  4
  4. (K904) O2 1/2 RETURN CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking O2 Sensor Circuit
    GC0099794Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the Powertrain Control Module (PCM) harness connector.
    3. Measure the resistance between ground and the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  8
  5. (K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 3: Checking O2 Sensor Circuit
    GC0099795Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (K141) O2 1/2 Signal circuit in the Oxygen Sensor 1/2 harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  6
  6. (K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 1/2 RETURN CIRCUIT 
    Fig 4: Checking O2 Sensor Circuit
    GC0099796Courtesy of CHRYSLER LLC
    1. Measure the resistance between the (K141) O2 1/2 Signal circuit and the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  7
  7. (K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO THE (K299) O2 1/2 HEATER CONTROL CIRCUIT 
    Fig 5: Checking O2 Sensor Circuit
    GC0099797Courtesy of CHRYSLER LLC
    1. Measure the resistance between the (K141) O2 1/2 Signal circuit and the (K299) O2 1/2 Heater Control circuit in the Oxygen Sensor 1/2 harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  8
  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.
    4. Refer to any Technical Service Bulletins (TSBs) that may apply.

      Were any problems found?

      Yes 

      No 

RENDER: 1.0x

NO RELATED

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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.