Trouble CodesGM OBD Trouble CodesGM Code 25

CODE 25 - Manifold Air Temperature Sensor

Trouble Code 25 indicates that the Manifold Air Temperature (MAT) sensor also known as the (IAT) Intake Air Temperature is reporting abnormally high readings. When the air is hot, the thermistor has a low resistance, which rises as the air temperature cools. High readings thus indicate a possible bad sensor or short in the MAT/IAT circuit.

The conditions for setting this code are:

  • MAT/IAT reading is > 275 deg F (135 deg C), and
  • the engine has been running for more than 16 seconds, and
  • the vehicle speed is > 40 MPH

Refer to the Code 25 description for typical sensor resistance values.

Typical causes for this code include:

1) Defective MAT/IAT sensor
2) MAT/IAT signal shorted to ground or to sensor ground
3) Defective ECM

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Chevy Trouble Codes