P0113

Code P0113, Intake Air Temperature (IAT) Sensor Circuit (High Temp Indicated):

Intake Air Temperature (IAT), Engine Coolant Temperature (ECT), Throttle Position (TP), And Trans Temperature Sensors Wiring Schematic:

CIRCUIT DESCRIPTION
The Intake Air Temperature (IAT) sensor is a thermistor. The PCM applies 5 volts on CKT 472 to the sensor. When the air is cold, the sensor resistance is high, and the PCM will measure a high signal voltage. If the air is warm, the sensor resistance is low causing the PCM to measure a low voltage.


DTC PO113 WILL SET WHEN:
^ Signal voltage indicates intake air temperature greater than 140°C (284°F).
^ Vehicle speed greater than 35 mph.
^ Both of the above conditions are met for 5 seconds.


ACTION TAKEN (PCM will default to):
With DTC P0113 set, the PCM will substitute a default value of 17°C (63°F for intake air temperature. DTC P0113 will not illuminate the MIL (Service Engine Soon) lamp.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. A Tech I may be used to diagnose this fault since the PCM transmits "actual" values when the fault is present. A grounded circuit will cause the Tech-1 to display a temperature of approximately 147°C (297°F).
2. If the Tech 1 displays -40° with the IAT sensor disconnected, the PCM and wiring are OK and the IAT sensor must be replaced.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness - Inspect PCM harness connectors for backed out terminals "BF7" and/or, "WC6", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

^ Intermittent test - Observe IAT on Tech-1 while moving related connectors and wiring harness with warm engine running. If the failure is induced, the IAT display will change to a -4O°F temperature reading. This may help to isolate the location of the malfunction.