P1112
CIRCUIT DESCRIPTIONThe 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. If the PCM detects an intermittently low signal voltage on the intake air temperature sensor signal circuit DTC P1112 will set.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0501 or P0502 are not set.
^ The engine has been running for over 10 seconds.
^ The vehicle speed is greater than 40 km/h (25 mph).
^ The above conditions are present for at least 5 seconds.
CONDITIONS FOR SETTING THE DTC
The IAT signal voltage intermittently indicates an intake air temperature greater than 135°C (275°F).
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
