Code P0113, IAT Sensor Circuit: Notes

The Intake Air Temperature (IAT) sensor is a thermistor. PCM applies and monitors 5 volts on circuit to sensor. When air is cold, sensor resistance is high and PCM will measure a high signal voltage. If air is warm, sensor resistance is low causing PCM to measure low voltage.

With Code P0113 set, PCM will use a default value of about 61°F (16°C) for intake air temperature. Code P0113 does not illuminate the Malfunction Indicator Light (MIL).

NOTE: Test numbers refer to numbers on diagnostic chart.

Tech-1 may be used to diagnose this fault since PCM transmits actual values when the fault is present. A grounded circuit will cause Tech-1 to display a temperature of about 297°F (147°C).
If Tech-1 displays -40° with IAT sensor disconnected, PCM and wiring are okay. Replace IAT sensor.