P0113

Circuit Description
The intake air temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The powertrain control module (PCM) applies 5 volts through a pull-up resistor to the AT sensor. When the intake air is cold, the sensor resistance is high and the PCM monitors a high signal voltage on the AT signal circuit. If the intake air is warm, the sensor resistance is lower causing the PCM to monitor a lower voltage. DTC P0113 sets when the PCM detects an excessively high signal voltage on the IAT sensor signal circuit.

Conditions for Running the DTC
^ No engine coolant temperature (ECT) sensor, mass air flow (MAF) sensor, or vehicle speed sensor (VSS) DTCs are present.
^ The engine has run for over 3 minutes.
^ The vehicle speed is less than 35 mph.
^ The MAF is less than 12 g/s.
^ The ECT is more than 60°C (140°F).

Conditions for Setting the DTC
^ The AT signal voltage indicates an intake air temperature less than -34°C (-29°F).
^ The above conditions are present for at least 20 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has run and failed.
^ The PCM stores the conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC
^ The PCM turns the MIL off during the third consecutive trip in which the diagnostic has run and passed.
^ The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Inspect for the following conditions:
^ A faulty connection at PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections.
^ Inspect the wiring harness for damage. If the harness appears to be OK, observe the IAT display on the scan tool while moving connectors and wiring harnesses related to the IAT sensor. A change in the IAT display indicates the location of the malfunction.
^ A skewed or mis-scaled IAT sensor.

If DTC P0113 cannot be duplicated, the information included in the Fail Records data may be useful in determining vehicle mileage since the DTC was last set.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
2. Verifies that the malfunction is present
3. If DTC P0113 can be repeated only by duplicating the Fail Records conditions. The Temperature vs Resistance table may be used to test the IAT sensor at various temperatures to evaluate the possibility of a shifted sensor that may be open above or below a certain temperature. If this is the case, replace the IAT sensor. If the IAT sensor appears to be OK, the malfunction is intermittent; refer to Diagnostic Aids.
11. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.