P0112 - INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW INPUT

The Input Air Temperature sensor (IAT) has the function of measuring the temperature of the air entering through the motor. It is important to know the value of the air temperature, taking into account that the greater the intake air, the higher the combustion temperatures will be. The high combustion temperatures are the result of increased nitrogen oxide emissions.

So that these high temperatures do not cause combustion temperatures, it is necessary that the intake air pipe is clean, since in this way the engine can in a certain sense breathe air that does not look like the engine compartment. The IAT sensor (Intake Air Temperature) uses a thermistor that has a reference signal of 5 volts from the Power Train Control Module (PCM) and also a ground.

Generally, when the air temperature is low, the resistance increases. And if, on the other hand, the air temperature is high, the resistance drops. This variation in resistance makes the 5 volt reference of the PCM (Powertrain Control Module) change and in this way, information is given to the PCM about the incoming air temperature. If the Powertrain Control Module (PCM) observes that the temperature of the incoming air is above the expected level, when it is possible that the engine temperature is low, the DTC code P0112 OBD2 is established.

• Check Engine light turns on.
• There may be difficulty when starting the engine.
• You may notice that the fuel lasts less.
• When accelerating you can perceive black smoke coming out of the exhaust.

Generally, if diagnostic code P0112 is established, it means that one or more of the following problems has occurred:

• There may be no reference voltage to the Input Air Temperature Sensor (IAT) possibly caused by a cable that is shorted.
• The IAT sensor ground circuit may be shorted.
• Admission temperatures may be excessively high.
• The IAT sensor may be defective.

To solve the P0112 code you can do the following:

• With a scanning tool, observe the readings of the IAT sensor (Input Air Temperature Sensor). If the engine is cold, this reading must be in accordance with the refrigerant reading, since both read the ambient temperature. In case the IAT sensor of a reading that shows a high level of excessive form, verify that the connector is not defective. If you do not find any damage in this, you can disconnect the sensor and reconnect it and proceed to verify the reading, which should be at a minimum of -20 degrees. If you do, you can change the IAT sensor.
• If the reading continues to show a high level, disconnect the sensor, and check the resistance through the 2 terminals of the cables. If the resistance is infinite, there may be a problem in the PCM (Power Train Control Module). If, on the contrary, the resistance is not infinite, it is indicative that there is a short circuit to ground in the signal circuit.