P0113

CIRCUIT DESCRIPTION
The Intake Air Temperature (IAT) sensor contains a thermistor which changes the resistance based on the temperature. The IAT sensor is located in the air intake passage of the engine air induction system. The IAT sensor has a signal circuit and a ground circuit. The PCM applies 5.0 volts on the signal circuit to the sensor. The PCM monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine intake air temperature.

When the intake air is cold, the sensor resistance is high. The PCM's signal voltage is only pulled down a small amount through the sensor to a ground. The PCM senses a high signal voltage, indicating a low temperature. When the intake air is warm, the sensor resistance is low. The signal voltage is pulled down more. The PCM senses a low signal voltage, indicating a high temperature.

When the PCM senses a signal voltage higher than the normal operating range of the sensor, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0502, or P0503 are not set.
^ The Engine Coolant Temperature (ECT) is more than 0°C (32°F).
^ The vehicle speed is less than 11 km/h (7 mph).
^ The Mass Air Flow (MAF) is less than 15 g/s.
^ The engine run time is more than 100 seconds.

CONDITIONS FOR SETTING THE DTC
^ The intake air temperature is less than -35°C (-31°F).
^ All conditions exist for more than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC "Last Test Failed" clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when you diagnose or replace the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the PCM.
^ For any test that requires probing the PCM or component harness connectors, use the J 35616-A connector test adapter kit. Using this kit prevents any damage to the harness connector terminals. Refer to Using Connector Test Adapters in Diagrams.

If the engine has sat overnight, the engine coolant temperature and the intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (5°F), refer to Temperature vs Resistance.

If you determine that the DTC occurs intermittently, performing the P1111 diagnostic table may isolate the cause of the fault. If a short to a separate 5-volt source occurs on the IAT signal circuit, this DTC may set. If this is found to be the problem, a continuity test to all other PCM circuits will be necessary to diagnose the specific circuit. Refer to DTC P1111. For an intermittent, refer to intermittent Conditions. P1111 Intermittent Conditions

TEST DESCRIPTION

Steps 1-8:

Steps 9-19:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the malfunction is present.
3. If DTC P1635 and DTC P1639 set at the same time, the signal circuit is shorted to a voltage.
4. Using the Freeze Frame/Failure Records may help to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. In order to isolate when the DTC failed, operate the vehicle within the same Freeze Frame conditions that you observed. These conditions include the following:
^ The RPM
^ The vehicle speed
^ The vehicle load
^ The temperature
5. An intake air temperature above 139°C (282°F) indicates that the PCM and the IAT sensor wiring is OK.
6. An intake air temperature above 139°C (282°F) indicates that the PCM and the IAT sensor signal circuit is OK.
7. Disconnecting the PCM allows you to use the DMM in order to test the continuity of the circuits. This procedure helps to locate an open circuit or a shorted circuit.
8. Disconnecting the PCM allows you to use the DMM in order to test for a short to voltage.