P0113

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Intake Air Temperature (IAT) sensor is a thermistor located in the fresh air duct to the throttle body in order to monitor the temperature of the air entering the throttle body. The VCM applies 5 volts to the sensor on the 5 volt reference circuit. When the air is cool, the resistance in the sensor measures high and the VCM senses a high voltage signal. If the air is warm, the sensor resistance measures low and the VCM senses a low voltage signal.

CONDITIONS FOR SETTING THE DTC

The following items will set the DTC:

^ No ECT sensor DTCs

^ No VS sensor DTCs

^ No MAF sensor DTCs

^ The vehicle speed less than 2 mph

^ The MAF is less than 250 g/s

^ The engine coolant temperature is greater than 84.7°C (185.5°F)

^ The engine run time is greater than 100 seconds

ACTION TAKEN WHEN THE DTC SETS

The VCM turns the MIL ON when P0113 is reported and 1 failure has occurred.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.

^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.

DIAGNOSTIC AIDS

A scan tool indicates the temperature of the ambient air which is entering the throttle body. The air temperature should read very close to the temperature of the outside air. The air temperature should rise gradually as the engine warms up and the underhood temperature increases. If DTC P1111 is set, the problem is intermittent. Check for an open in the IAT sensor circuit. This may be accomplished by moving the VCM harness at various locations and monitoring IAT temperature or IAT voltage on the scan tool. If the voltage varies, look for an open in the area of the harness that caused the variance Also, a sensor may become skewed or mis-scaled. The Temperature vs. Resistance Value Table will help in order to detect a skewed sensor. Refer to Specifications / Electrical / Temperature vs Resistance.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

IMPORTANT: Use the same diagnostic test equipment for all the measurements.

2. If the IAT sensor circuit voltage measures greater than 4.90 volts, the conditions for the DTC are still present, and the problem is not intermittent.

3. This test will bypass the IAT sensor and will confirm that the IAT signal circuit and the sensor ground circuit to the VCM are sound. Grounding the signal circuit will provide a low voltage input to the VCM. The VCM should recognize this low voltage and indicate a high IAT temperature.

4. This test determines if the IAT sensor signal circuit is okay. If the scan tool does not indicate a high temperature, the IAT signal circuit is open.