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Home › Dodge and Ram › 2003 › Grand Caravan Base › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes - 3.3L & 3.8L › Diagnostic Tests › DTC P0134: 1/1 O2 Sensor Stays At Center Or DTC P0140: 1/2 O2 Sensor Stays At Center › Testing

DTC P0134: 1/1 O2 Sensor Stays At Center Or DTC P0140: 1/2 O2 Sensor Stays At Center: Testing

NOTE: Before continuing check for contaminants that may have damaged HO2S such as contaminated fuel, unapproved silicone, oil and coolant.
  1. Turn the ignition on. With the DRBIII® scan tool, read DTCs. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, refer to the INTERMITTENT CONDITION  under SELF-DIAGNOSTICS SYSTEM.
  2. Turn the ignition off. Disconnect the O2 sensor harness connector. Turn the ignition on. Connect a test light to battery voltage, probe the O2 sensor signal circuit in the O2 sensor harness connector. With the DRBIII® scan tool, read the O2 sensor voltage. Is the voltage above 1.0 volts? If yes, replace the O2 sensor. If no, go to next step.
  3. Turn the ignition off. Disconnect the O2 sensor harness connector. Disconnect the Powertrain Control Module (PCM) harness connectors. Measure the resistance of the O2 sensor ground circuit between the O2 sensor harness connector and the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to the next step. If no, repair the (K127) O2 sensor ground circuit for an open.
  4. Turn the ignition off. Disconnect the O2 sensor harness connector. Disconnect the PCM harness connector. Measure the resistance of the O2 sensor signal circuit between the O2 sensor harness connector and the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the O2 sensor signal circuit for an open.
    5. WARNING: When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.
    NOTE: Ensure the voltmeter leads meet the terminals in the connector and that there is good terminal to wire connection. Ensure the voltmeter leads are connected for positive polarity.
  5. Ensure ignition is off. Reconnect O2 sensor and PCM harness connectors. Perform a voltage drop test by back probing between the O2 sensor ground circuit at the O2 sensor harness connector and PCM harness connector. Start the engine. Allow the engine to idle. Is the voltage below 0.10 volt? If yes, go to next step. If no, repair the high resistance on the (K127) O2 sensor ground circuit.
    6. NOTE: Ensure the voltmeter leads meet the terminals in the connector and that there is good terminal to wire connection. Ensure the voltmeter leads are connected for positive polarity.
  6. Perform a voltage drop test by backprobing between the O2 sensor signal circuit at the O2 sensor harness connector and PCM harness connector. Start the engine. Allow the engine to idle. Is the voltage below 0.10 volt? If yes, go to next step. If no, repair the high resistance on the O2 sensor signal circuit.
    7. NOTE: Before continuing disconnect the PCM harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.
  7. Using the wiring diagram as a guide, inspect the wire harness and connectors. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace and program the PCM. See PROGRAMMING .
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