Technical Description of OBD-II Trouble Code
Low Input Bank 2 for Intake Air Temperature Sensor 2 Circuit
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The intake air temperature (IAT) sensor is responsible for measuring the temperature of the air entering the engine. The intake air temperature is crucial because higher intake air temperatures lead to higher combustion temperatures. Increased combustion temperatures result in higher emissions of nitrogen oxides (Nox).
To prevent these higher temperatures from causing increased combustion temperatures, it is important for the intake air tubing to be intact, allowing the engine to “breathe” air that is not sampled from the engine compartment. The IAT sensor measures air temperature using a thermistor or a thermometer. The thermistor receives a 5-volt reference voltage from the powertrain control module (PCM) and a ground. Typically, when the air temperature is cold, the resistance in the thermistor is high, and when the air temperature is warmer, the resistance decreases.
This change in resistance alters the 5-volt reference from the PCM, thereby informing the PCM about the temperature of the incoming air. If the PCM detects that the temperature of the incoming air from bank 2 sensor #2 is unusually high, such as 300 degrees, when the engine temperature is still relatively low, it will set a P00A7 code. Bank 2 refers to the side of the engine that does not contain cylinder #1.
Other related trouble codes for bank 2 sensor 2 of the intake air temperature sensor include:
Symptoms
There may not be any noticeable symptoms of a P00A7 code other than the Malfunction Indicator Lamp (MIL) being illuminated. However, an emissions test may reveal higher Nox readings depending on the type of IAT failure. Additionally, the engine may ping under load depending on the type of IAT failure.
Causes
Usually, the P00A7 code is caused by a faulty #2 IAT sensor (internally shorted, open, or otherwise damaged). However, it could also be caused by:
Possible Solutions
Connect a scan tool or code reader and check the IAT reading. With a cold engine, the IAT reading should roughly match the coolant reading since both readings reflect the ambient temperature. If the IAT #2 reading is excessively high, inspect the IAT connector for any damage. If no damage is found, unplug the IAT sensor and recheck the reading. It should now read the minimum temperature, around -20 degrees. If it does, then replace the IAT sensor #2.
However, if the reading is still high, unplug the sensor and check for resistance across the two wiring harness terminals. If there is infinite resistance, then the PCM itself is faulty. If the resistance is not infinite, then inspect and repair any short to ground on the signal circuit.
