P1111
CIRCUIT DESCRIPTION
The Intake Air Temperature (IAT) sensor contains a semiconductor device, a thermistor, which changes the resistance based on the temperature. The IAT sensor has a signal circuit and a ground circuit. The Powertrain Control Module (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 IAT.
When the intake air is cold, the sensor or thermistor resistance is high. The PCM signal voltage only pulls down a small amount through the sensor to a ground. Therefore, the PCM senses a high signal voltage or low temperature. When the intake air is warm, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the PCM senses a low signal voltage, or a high temperature.
When the PCM senses a signal voltage higher than the normal operating range of the sensor, this Diagnostic Trouble Code (DTC) sets.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0102, P0103, P0117, P0118, P0502, or P0503 are not set.
^ The engine run time is more than 100 seconds.
^ 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 is less than 15 g/s.
CONDITIONS FOR SETTING THE DTC
^ The Intake Air Temperature (IAT) is less than -35°C (-31°F).
^ The intermittent condition exists for a total of 1 second during a 20-second time period.
ACTION TAKEN WHEN THE DTC SETS
^ The control module stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.
CONDITIONS FOR CLEARING THE DTC
^ 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 non-emission related diagnostic.
^ Use a scan tool in order to clear the DTC.
DIAGNOSTIC AIDS
IMPORTANT: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
If the engine has sat overnight, the engine coolant temperature and intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (37°F), refer to Temperature vs Resistance. Temperature VS Resistance
When moving related connectors, visually and physically inspect connectors for the following conditions:
^ Poor mating of the connector halves or a terminal not fully seated, or backed out, in the connector body
^ Improperly formed or damaged terminal-Carefully reform or replace all connector terminals in the related circuits in order to insure proper terminal contact tension.
^ Poor terminal to wire connection-Inspect for poor crimps or crimping over the wire insulation rather than the wire.
^ Dirt or corrosion on the terminals-Inspect the connector seals for damage.
For an intermittent, refer to Intermittent Conditions. Intermittent Conditions
TEST DESCRIPTION
Steps 1-10:
The numbers below refer to the step numbers on the diagnostic table.
2. If DTC P0113 failed this ignition, this indicates a hard failure is present. When a hard failure is present, both the hard and intermittent DTCs set.
3. This step inspects for the proper connections.
4. This step inspects the wiring harness.
5. Using the Freeze Frame/Failure Records data may aid in locating 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. Operate the vehicle within the same Freeze Frame conditions such as the engine RPM, the engine load, the vehicle speed, the temperature etc., that you observed. This will isolate when the DTC failed. For any test that requires probing the PCM or component harness connectors, use the Connector Test Adapter kit. Using this kit prevents any damage to the harness connector terminals.