DTC P0111 - IAT Sensor Circuit Performance: Notes
WARNING: This page is about a different car, the 1998 Cadillac Seville, 1998 Cadillac Eldorado, and 1998 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For circuit reference, see ENGINE PERFORMANCE - WIRING DIAGRAMS
article.
The IAT sensor is a thermistor that varies resistance based on temperature. Low temperature will result in a high signal voltage. This test monitors IAT sensor voltage. If PCM detects a large change in IAT sensor signal voltage in a .25 second period, DTC will set.