P00AA – Intake Air Temperature Sensor 1 Circuit

Reinier

By Reinier (Contact Me)
Last Updated 2018-07-27
Automobile Repair Shop Owner

Trouble CodeFault LocationProbable Cause
P00AA Intake Air Temperature Sensor 1 Circuit -

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What Does Code P00AA Mean?

OBD II fault code P00AA is a generic code that is defined as “Intake Air Temperature Sensor 1 Circuit Bank 2”, and is set when the PCM (Powertrain Control Module) detects a failure in the control and or signal circuit(s) of the intake air temperature sensor on bank 2. Note that “Bank 2” refers to the bank on cylinders that does not contain cylinder #1 on V-type engines.

In practice, there is a direct correlation between the temperature and density of atmospheric air; the colder the air, the denser the air is, with the corollary that the hotter the air is, the less dense it is, and the function of an intake air temperature sensor is to measure the actual temperature of the intake air that enters the engine.

While modern engine management systems can measure both the volume and temperature of the amount of air that flows through the inlet tract, these systems cannot control the rate at which air flows through the inlet tract, since this changes constantly as a result of both changes in engine speed and throttle position.

However, since modern engine and fuel management systems can control the amount of fuel that is injected at any given moment regardless of operating conditions, it uses input data from sensors such as the MAF (Mass Airflow) sensor, MAP (Manifold Absolute Pressure sensor if fitted), and the Intake Air temperature sensor(s) among others,  to calculate a fuel delivery strategy to suit the volume of air that is entering the engine.

As a practical matter, if the ambient temperature is very low, the intake air will be more dense than it would have been at very high ambient temperatures. Thus, in order to maintain an ideal air/fuel mixture, regardless of the density of the intake air, the PCM uses input data from the intake air temperature sensor to calculate the amount of fuel to inject to maintain an ideal air/fuel mixture. For instance, if the intake air is cold and dense the PCM will inject more fuel, since more air can be packed into inlet tract, while if the intake air is hot and rarified, the PCM will inject less fuel, since less fuel is required to bring the air/fuel ratio into the 14.7 parts of air to 1 part of fuel range.

From the above, it should be obvious that intake air temperature sensors play a critically important role in efficient engine management, and if a failure, defect, or malfunction exists that causes the sensor not to work, or to deliver inaccurate or implausible data to the PCM, the PCM will recognize that it cannot control the air/fuel mixture effectively. When this happens, the PCM will set code P00AA, and illuminate a warning light.

Where is the P00AA sensor located?

The image above shows the location (circled) of an intake air temperature sensor in the inlet tract of a VW application. However, it is important to note that the appearance and location of intake air temperature sensors vary greatly between applications. Therefore, it is important always to refer to the manual for the affected application to locate and identify intake air temperature sensors correctly, since other, unrelated sensors may also be located in the inlet tract.

However, intake air temperature sensors are typically also located directly on the inlet manifold, or in some cases, may be incorporated into the throttle body.

What are the common causes of code P00AA?

Some common causes of code P00AA could include the following-

  • Damaged, burnt, shorted, disconnected, or corroded wiring and or connectors in the sensors’ control/signal circuits
  • Defective intake air temperature sensor
  • Failed or failing PCM, but this a rare event, and the fault must therefore be sought elsewhere before any control module is replaced

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