CODE 23 - Manifold Air Temperature Sensor
Trouble Code 23 indicates that the Manifold Air Temperature (MAT) sensor also known as the (IAT) Intake Air Temperature is reporting abnormally low readings. When the air is cold, the thermistor in the sensor has a high resistance, which falls as the air charge warms. Low readings thus indicate a possible bad sensor or open in the MAT circuit.
The conditions for setting this code are:
NOTE: A default MAT/IAT value indicating 82 deg F is used while Code 23 is present.
Typical thermistor resistance values are:
Typical causes for this code include: