WOMS
P code powertrain Medium severity

P0099 Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic

The OBD2 code P0099 indicates that there is an intermittent or erratic signal from the Intake Air Temperature Sensor 2, which measures the temperature of the air entering the engine

Definition

The OBD2 code P0099 indicates that there is an intermittent or erratic signal from the Intake Air Temperature Sensor 2, which measures the temperature of the air entering the engine

Common causes

  • Faulty intake air temperature sensor 2
  • Poor electrical connections or wiring issues
  • Short circuit in the sensor circuit
  • Open circuit in the sensor circuit
  • Corroded or damaged connectors
  • Faulty engine control module (ECM)
  • Intermittent sensor signal
  • Vacuum leaks affecting sensor readings

Common misdiagnoses

  • Faulty Intake Air Temperature Sensor
  • Wiring issues or damaged connectors
  • Faulty Engine Control Module (ECM)
  • Vacuum leaks
  • Faulty Mass Air Flow (MAF) sensor
  • Air filter blockage
  • Faulty coolant temperature sensor
  • Issues with the intake manifold or throttle body

Troubleshooting steps

  1. 1. Check the Vehicle's Service Manual

    Refer to the specific service manual for your vehicle to understand the IAT sensor's location, wiring diagrams, and specifications

  2. 2. Visual Inspection

    Wiring and Connectors: Inspect the wiring and connectors associated with the IAT sensor for any signs of damage, corrosion, or loose connections

  3. 3. Sensor Condition

    Check the physical condition of the IAT sensor. Look for cracks, dirt, or other contaminants

  4. 4. Scan for Codes

    Use an OBD-II scanner to check for any additional trouble codes that may be present. This can provide more context for the issue

  5. 5. Check Sensor Voltage and Ground

    Power Supply: Use a multimeter to check the voltage at the IAT sensor connector. Ensure it is receiving the correct voltage as specified in the service manual

  6. 6. Ground

    Verify that the ground connection for the sensor is intact and has a good connection

  7. 7. Test the IAT Sensor

    Resistance Check: Measure the resistance of the IAT sensor at different temperatures to ensure it is functioning within the specified range. Compare your readings with the manufacturer's specifications

  8. 8. Temperature Response

    If possible, test the sensor in a controlled environment to see if it responds correctly to temperature changes

  9. 9. Check for Air Leaks

    Inspect the intake system for any air leaks that could affect the readings of the IAT sensor. This includes checking hoses, gaskets, and the intake manifold

  10. 10. Inspect the Engine Control Module (ECM)

    Ensure that the ECM is functioning properly. Sometimes, issues with the ECM can lead to erratic sensor readings

  11. 11. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears

  12. 12. Replace the Sensor (if necessary)

    If the sensor is found to be faulty during testing, replace it with a new one

  13. 13. Professional Diagnosis

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or technician who has experience with your vehicle make and model.Additional Tips: - Always ensure that you are working safely and that the vehicle is in a secure position. - Keep in mind that intermittent issues can sometimes be challenging to diagnose, so thoroughness is key. By following these steps, you should be able to identify and resolve the issue related to the P0099 code