Examination
1. The IAT sensor is a thermistor (resistor whose resistance depends on temperature). A change in resistance entails a change in the amplitude of the signal voltage of the sensor, and the HIGHER the temperature, the LOWER the resistance, and vice versa. Sensor failures lead to the recording of a fault code P0112 or P0113 in the memory of the self-diagnosis system.
2. Check the resistance of the IAT sensor. Disconnect the connector of the electrical wiring of the sensor located on the inlet pipeline.
3. Using an ohmmeter, measure the resistance between the two terminals on the sensor. The resistance of the sensor depends on the temperature and at 20°C should be approximately 2500÷3500 Ohm. Start the engine (or remove the sensor and warm it up with a hair dryer). At 83°C, the sensor resistance should drop to 250÷350 Ohm. If the test fails, replace the IAT sensor.
Note. If the engine was running with the sensor disconnected, do not forget to clear the memory of the self-diagnosis system (see Section On-Board Diagnostic System (OBD) - the principle of operation and fault codes).
Replacement
1. Disconnect the negative cable from the battery.
Attention! If the stereo system installed in the car is equipped with a security code, before disconnecting the battery, make sure that you have the correct combination to activate the audio system!
2. Disconnect the electrical wiring from the IAT sensor.
3. Remove the sensor from the casing of the discharge chamber of the intake air path.
4. Installation is carried out in the reverse order.