P0113
CIRCUIT DESCRIPTIONThe intake air temperature (IAT) sensor is a variable resistor, sometimes called a thermistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance lowers. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0128, P0502, or P0503 are not set.
^ The engine run time is more than 120 seconds.
^ The vehicle speed sensor indicates that vehicle speed is less than 11 km/h (7 mph).
^ The engine coolant temperature is more than 60°C (140°F).
^ The mass air flow is less than 15 g/s.
CONDITIONS FOR SETTING THE DTC
The IAT sensor signal voltage indicates that the intake air temperature is less than -39°C (-38°F) for more than 5 seconds.
DIAGNOSTIC AIDS
^ When the vehicle is at ambient temperature the IAT sensor and ECT sensor temperatures should be relatively close to each other. Refer to Temperature vs Resistance. [1][2]Computers and Control Systems
^ If a short to a separate 5-volt source occurs this DTC may set. If this condition exists, a continuity test to all other PCM 5-volt reference circuits will be necessary.
^ If an intermittent condition is suspected, refer to Intermittent Conditions. Intermittent Conditions
TEST DESCRIPTION
Steps 1-7:
Steps 8-15:
The number below refer to the step number on the diagnostic table.
6. This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.