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 IAT sensor. When the intake air is cold, the sensor resistance is high and the PCM will monitor a high signal voltage on the IAT signal circuit. If the intake air is warm, the sensor resistance is lower causing the PCM to monitor a lower voltage. DTC P0113 will set when the PCM detects an excessively high signal voltage on the intake air temperature sensor signal circuit.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0117, P0118 P0125, P0128, P0502, P0503, P1114, P1115 are not set.
^ The engine has been running for over 3 minutes.
^ Vehicle speed is less than 5 mph.
^ Mass air flow is less than 8 g/s.
^ Engine coolant temperature is more than 60°C (140°F).

CONDITIONS FOR SETTING THE DTC
^ IAT signal voltage indicates an intake air temperature less than -38°C (-37°F).
^ The above conditions are present for at least 110 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ First failure:
- The MIL is not turned ON.
- A DTC is stored in memory under Failed Last Test.
- The Failure Records are stored.
^ Second consecutive drive cycle with a failure:
- The MIL is turned ON.
- A DTC is stored in memory under history.
- The Freeze Frame data is stored.
- The Failure Records are stored.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after the third consecutive trip the diagnostic has run and passed.
^ The history DTC will clear if the fault conditions have not been detected for 40 warm-up cycles.
^ A scan tool can be used to clear DTC information.

DIAGNOSTIC AIDS
Check for the following conditions:
^ Poor connection at PCM.
Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. If DTC P0113 cannot be duplicated, the information included in the Failure Records data can be useful in determining vehicle mileage since the DTC was last set.
^ Damaged harness.
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 will indicate the location of the malfunction.
^ Skewed or mis-scaled IAT sensor - Refer to Temperature vs Resistance.
^ If a short to a separate 5-volt source occurs this DTC may set. If this is found to be a problem, a continuity test to all other PCM circuits will be necessary to diagnose the specific circuit.

TEST DESCRIPTION

Steps 1-8:

Steps 9-14:

The numbers below refer to the step numbers on the diagnostic table.
2. Verifies that the malfunction is present.
3. If DTC P0113 can be repeated only by duplicating the Failure Records conditions. The 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.
12. 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.