P1112
CIRCUIT DESCRIPTIONThe Intake Air Temperature Sensor (IAT) is a thermistor (a variable resistor) that measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) supplies 5 volts to the IAT signal circuit through a pull-up resistor. When the intake air is cold, the PCM detects a high voltage on the IAT signal circuit. As the intake air warms, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an intermittently low IAT signal voltage (high temperature indicated), this Diagnostic Trouble Code (DTC) will set.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0502, P0503, P1114, or P1115 are not set.
^ The Engine Coolant Temperature (ECT) is less than 100°C (212°F).
^ The vehicle speed is more than 15 km/h (9 mph).
CONDITIONS FOR SETTING THE DTC
^ The IAT sensor signal voltage is less than 0.25 volts. This would be approximately 133°C (271°F).
^ The condition exists for less than 1 second.
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
If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions
TEST
