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P code powertrain Medium severity

P1119 Manifold Absolute Temperature Circuit High Input

The OBD2 code P1119 indicates that the Manifold Absolute Temperature (MAT) sensor circuit is sending a high voltage signal, which suggests a potential issue with the sensor or its wiring

Definition

The OBD2 code P1119 indicates that the Manifold Absolute Temperature (MAT) sensor circuit is sending a high voltage signal, which suggests a potential issue with the sensor or its wiring

Common causes

  • Faulty manifold absolute temperature (MAT) sensor
  • Open or shorted wiring in the MAT sensor circuit
  • Poor electrical connections or corroded connectors
  • Faulty engine control module (ECM)
  • Incorrectly installed or damaged intake manifold
  • Vacuum leaks in the intake system
  • High resistance in the sensor circuit

Common misdiagnoses

  • Faulty Manifold Absolute Temperature (MAT) sensor
  • Wiring issues or short circuits in the MAT circuit
  • Faulty Engine Control Module (ECM)
  • Vacuum leaks
  • Faulty intake air temperature sensor
  • Issues with the mass air flow (MAF) sensor
  • Problems with the throttle position sensor (TPS)
  • Incorrectly calibrated or installed aftermarket parts

Troubleshooting steps

  1. 1. Check the Vehicle's Service Manual

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

  2. 2. Visual Inspection

  3. 3. Inspect the MAT sensor and its wiring for any visible damage, such as frayed wires, corrosion, or loose connections

  4. 4. Check the connector for any signs of moisture or dirt that could affect the sensor's performance

  5. 5. Test the MAT Sensor

  6. 6. Disconnect the MAT sensor and measure its resistance with a multimeter. Compare the readings to the specifications in the service manual

  7. 7. If the resistance is out of range, the sensor may be faulty and should be replaced

  8. 8. Check the Voltage Supply

  9. 9. With the ignition on (engine off), use a multimeter to check the voltage at the MAT sensor connector. It should typically be around 5 volts (check the specific value for your vehicle)

  10. 10. If the voltage is higher than expected, there may be an issue with the power supply or a short circuit

  11. 11. Inspect the Ground Circuit

  12. 12. Ensure that the ground connection for the MAT sensor is secure and free of corrosion. A poor ground can lead to incorrect readings

  13. 13. Check for Short Circuits

  14. 14. Inspect the wiring harness for any signs of short circuits or damaged insulation that could cause the high input signal

  15. 15. Scan for Additional Codes

  16. 16. Use an OBD-II scanner to check for any other trouble codes that may be related to the MAT sensor or other engine management systems. This can provide additional context for the issue

  17. 17. Clear the Code and Test Drive

  18. 18. After performing the checks and repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  19. 19. Replace the MAT Sensor

  20. 20. If all other checks are normal and the code persists, consider replacing the MAT sensor, as it may be faulty

  21. 21. Consult a Professional

  22. 22. If you are unable to diagnose or resolve the issue, it may be best to consult a professional mechanic or technician who has experience with OBD-II systems. By following these steps, you should be able to identify and resolve the issue related to the P1119 code