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Home >> Jeep >> 2003 >> Wrangler Rubicon, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 14 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0135: 1/1 O2 Sensor Heater Failure, DTC P0141: 1/2 O2 Sensor Heater Failure, DTC P0155: 2/1 O2 Sensor Heater Failure Or DTC P0161: 2/2 O2 Sensor Heater Failure >> Testing

DTC P0135: 1/1 O2 Sensor Heater Failure, DTC P0141: 1/2 O2 Sensor Heater Failure, DTC P0155: 2/1 O2 Sensor Heater Failure Or DTC P0161: 2/2 O2 Sensor Heater Failure: Testing

WARNING: This page is about a different car, the 2003 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down before continuing the test.
  1. Turn ignition on, engine not running. With the DRBIII®, actuate the O2 Heater Test. With the DRBIII®, monitor O2 Sensor voltage for at least 2 minutes. Does the voltage stabilize between 0.1 and 0.3 volt during the Heater test? If yes, go to INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
  2. Turn ignition off. Allow HO2S to cool down to room temperature. Disconnect the O2 Sensor harness connector related to DTC. Measure the resistance across the O2 Sensor Heater element component side. The resistance value increases with temperature. Is the resistance for a 4.0L O2 Heater element between 4.0 and 5.0 ohms and 12.1 to 14.8 ohms for a 4.7L O2 Heater element (70°F, 21.1°C)? If yes, go to next step. If no, replace the O2 Sensor.
    3. NOTE: This test depends on the type of Heated O2 Sensor being tested. The Pulse Width Modulated (PWM) Heated O2 Sensor uses the ASD Relay to supply voltage to the heater element and the other type of Heated O2 Sensor uses an O2 Sensor Downstream Relay.
  3. Turn ignition on, engine not running. With the DRBIII®, actuate the O2 Heater Test. Measure the voltage on the O2 Heater supply circuit at the O2 Sensor harness connector. Is the voltage above 10.0 volts? If yes, go to next step. If no, repair the open in the O2 Sensor Heater Supply circuit.
  4. Turn the ignition off. Disconnect the PCM harness connectors. Remove the O2 Heater Relay, if it applies to the O2 Sensor being tested. Measure the resistance of the O2 Heater Control circuit (PWM) from the O2 Sensor to the PCM harness connector if it applies to the O2 Sensor being tested. Otherwise, the second option is to measure the resistance of the (K512) O2 Heater Relay Control circuit from the O2 Heater Relay to the PCM harness connector, if it applies to the O2 Sensor being tested. Is the resistance below 5.0 ohms? If yes, go to the next step. If no, repair the excessive resistance in the O2 Heater Control circuit.
    5. NOTE: Before beginning this test, verify what type of Heated O2 Sensor is being tested, either the PWM Heated O2 Sensor or the Heater Relay controlled Heated O2 Sensor.
  5. Measure the resistance between ground and the PWM circuit if it applies to the Heated O2 Sensor being tested. Otherwise, the second option is to measure the resistance between ground and the (K512) Heater Control circuit if it applies to the Heated O2 Sensor being tested. Is the resistance below 100 ohms? If yes, repair the short to ground in the O2 Heater Control circuit. If no, go to the next step.
    6. NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
  6. Using the wiring diagram as a guide, inspect the wire harness and connectors. Pay particular attention to all power and ground circuits. There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
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