Intake Air Temperature (IAT)
DIAGNOSTIC CODES: P0112, P0113The range is checked for values outside the limits. If these tests are not passed then a fault event is recorded and if the count exceeds a given limit then a fault is registered. While fault counting is in progress a back-up value of air temperature will be supplied and when faults are present a default value of air temperature will be supplied. The strategy will report to the Diagnostic Status Manager (DSM) when all the tests have been performed once; the DSM will then decide whether to store a fault code and illuminate the MIL.
IAT Circuit Low Input, Diagnostic Code P0112
The IAT output is checked for intake values outside expected limits.
- High temperature threshold 180 °C.
- Low temperature threshold 39 °C.
Possible causes:
- Temperatures have been very cold (sub -50 °C)
- IAT disconnected
- IAT harness open circuit or high resistance
- IAT signal short circuit to battery voltage
- IAT sensor fault - open circuit or high resistance
- ECM interface circuit fault
IAT Circuit High Input, Diagnostic Code P0113
A range check on the output of the air temperature sensor is performed to check for intake values outside expected limits.
Possible causes:
- Temperatures have been very hot - engine has boiled
- IAT harness wires short circuit to ground
- IAT fault - low resistance
- ECM interface circuit fault
For more information about this sensor, please see Computers and Control Systems, Intake Air Temperature Sensor. Description and Operation