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DTC P0111: Intake Air Temp Sensor Performance: Testing

  1. Turn ignition on, engine not running. With the DRBIII®, read DTCs. Is the Good Trip counter equal to zero? If yes, go to next step. If no, see INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn the ignition off. Disconnect the Intake Air Temperature Sensor harness connector. Turn ignition on, engine not running. With the DRBIII®, read the IAT voltage. Is the voltage above 4.6 volts? If yes, go to next step. If no, go to step  4.
  3. Turn the ignition off. Using a jumper wire, jumper across the IAT Sensor harness connector. Turn ignition on, engine not running. With the DRBIII®, read the IAT voltage. Is the voltage below 1.0 volt? If yes, replace the Intake Air Temperature Sensor. If no, go to next step.
    NOTE: Remove the jumper wire and connect the sensor harness connector before continuing.
    4. 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.
  4. Turn the ignition off. Perform a voltage drop test of the Sensor signal circuit by backprobing the (K21) IAT Sensor signal circuit at the IAT 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 in the (K21) IAT Sensor signal circuit.
    5. 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.
    NOTE: Turn the ignition off before continuing.
  5. Turn the ignition off. Perform a voltage drop test of the IAT Sensor ground circuit by backprobing the IAT 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 in the IAT Sensor ground circuit.
    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. If there are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
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