Circuit Description: Notes
WARNING: This page is about a different car, the 2005 Suzuki Swift +, 2005 Pontiac Wave, and 2005 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. If the ECM detects the difference between the start-up coolant temperature and the start-up intake air temperature is more than a predetermined amount, this DTC sets. This DTC also sets if the current intake air temperature is more than a predetermined amount based on the start-up engine coolant temperature.
The following table illustrates the difference between temperature, resistance, and voltage:
DTC P0111
| IAT | IAT Resistance | IAT Signal Voltage |
|---|---|---|
| Cold | High | High |
| Warm | Low | Low |