P1111

Diagnostic Chart:

Engine Controls Schematics: A/C Refrigerant Pressure Sensor, TP, MAP, ECT and IAT Sensor:

CIRCUIT DESCRIPTION
The Intake Air Temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The PCM applies 5.0 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 P1111 will set when the PCM detects an intermittently high signal voltage on the intake air temperature sensor signal circuit.

CONDITIONS FOR RUNNING THE DTC
^ No active ECT, MAF sensor, VSS DTC present.
^ Vehicle speed is less than 35 mph.
^ The mass air flow is less than 12 g/s.
^ The engine coolant temperature is greater than 60°C (140°F).
^ Engine run time more than 3 minutes.

CONDITIONS FOR SETTING THE DTC
^ IAT signal voltage indicates an intake air temperature intermittently less than -37°C (-35°F).
^ The conditions is present for up to 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Inspect for the following conditions:

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection.
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams for diagnosis and repair.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Diagrams for diagnosis and repair.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.