For 1990-2009 cars

The intake air temperature sensor is an integral part of the mass air flow sensor (MAF). The intake air temperature (IAT) sensor is a thermistor that varies resistance according to changes in air induction temperature. The ECM supplies a 5-volt reference through a pull-up resistor to the sensor, which is connected to a ground. When the sensor is cold it has high resistance (high signal voltage at ECM). As the sensor temperature increases, its resistance decreases (lower signal voltage at ECM). The ECM uses the signal voltage to determine air induction temperature. DTC P0113 sets when the IAT sensor signal voltage at the ECM is above the calibrated voltage value (below the calibrated temperature value).

### DTC PARAMETERS

DTC P0113 will set if the IAT temperature is below -39°C (-38°F) when:

• | The condition exists for longer than 2 seconds.

• | The engine run time is greater than 1 minute and 20 seconds.

• | The engine has been at idle for at least 10 seconds.

DTC P0113 diagnostic runs continuously once the above conditions have been met.

P0113 is a type B DTC.

### DIAGNOSTIC AIDS

To locate an intermittent problem, use the scan tool to monitor the IAT temperature with the ignition On, and the engine Off. Wiggling the wires while watching for a change in the IAT temperature may locate the area where an open or short to voltage in the wiring could lie.

The CMP/ECT/IAT/EGR/MAF/MAP/TP1/TP2 sensors share the same sensor return circuit 652.

Refer to the ECT General Description for the Temperature vs. Resistance chart.

Important: A direct short to voltage on circuit 652 may cause internal damage to the ECM ground trace, or open the sensor element in the ECT, IAT and/or MAP sensors.