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P0112 Intake Air Temperature Circuit Low Input

The OBD2 code P0112 indicates that the engine control module (ECM) has detected a low voltage signal from the intake air temperature (IAT) sensor, suggesting a potential issue with the sensor or its circuit

Definition

The OBD2 code P0112 indicates that the engine control module (ECM) has detected a low voltage signal from the intake air temperature (IAT) sensor, suggesting a potential issue with the sensor or its circuit

Common causes

  • Faulty intake air temperature sensor
  • Open or shorted wiring in the intake air temperature circuit
  • Poor electrical connections
  • Corroded connectors
  • Faulty engine control module (ECM)
  • Vacuum leaks
  • Damaged or disconnected intake air ducting

Common misdiagnoses

  • Faulty Mass Air Flow (MAF) Sensor
  • Faulty Engine Coolant Temperature (ECT) Sensor
  • Vacuum Leaks
  • Faulty Engine Control Module (ECM)
  • Wiring Issues or Short Circuits
  • Faulty Intake Air Temperature (IAT) Sensor
  • Air Filter Restrictions
  • Throttle Position Sensor (TPS) Issues

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can help identify if there are related issues

  2. 2. Inspect the IAT Sensor

    Locate the IAT sensor, which is usually found in the intake manifold or air intake duct

  3. 3. Check for physical damage to the sensor or its connector

  4. 4. Ensure that the sensor is properly connected and that there are no bent pins or corrosion

  5. 5. Test the IAT Sensor

    Use a multimeter to measure the resistance of the IAT sensor. Compare the readings to the specifications provided in the vehicle's service manual

  6. 6. If the resistance is outside the specified range, the sensor may be faulty and should be replaced

  7. 7. Check Wiring and Connectors

    Inspect the wiring harness and connectors leading to the IAT sensor for any signs of damage, fraying, or corrosion

  8. 8. Look for any loose connections or broken wires that could cause a poor signal

  9. 9. Check for Short Circuits or Open Circuits

    Use a multimeter to check for continuity in the wiring between the IAT sensor and the ECM

  10. 10. Check for any short circuits to ground or power that could affect the sensor's signal

  11. 11. Inspect the Air Intake System

    Check for any obstructions or leaks in the air intake system that could affect the air temperature readings

  12. 12. Ensure that the air filter is clean and not clogged

  13. 13. Check Engine Coolant Temperature (ECT) Sensor

    Sometimes, issues with the ECT sensor can affect the IAT readings. Check the ECT sensor for proper operation

  14. 14. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  15. 15. Take the vehicle for a test drive to see if the code reappears

  16. 16. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P0112 code