The 3 main reasons for a defective throttle body

A throttle body: in order to function properly, it must be in good condition. In practice, however, there are often problems with throttle bodies, which can be found between the air filter and the engine. In this article we will discuss the operation of a throttle body, the main symptoms of a defective throttle body, the possible causes and the possible solutions that we can offer.

throttle body defect

The operation of a throttle body

The throttle body is an important part of many petrol engines; it is located between the air filter and the engine. The throttle body, with the throttle valve position, controls the amount of air that passes through to the engine according to the position of the throttle pedal. The further the throttle is pressed, the more air will be let through to the engine, the better the cylinders will be filled and the more powerful the combustion in the cylinders will be. The torque and power developed by the engine will therefore increase when the accelerator pedal is depressed, and that is exactly what the driver requires of the engine at that moment.

Main symptoms of defective throttle bodies

As said before, there are often problems with the throttle body. That there are problems with the throttle body is often noticeable by a badly running engine. The idling speed can be irregular, the engine can react badly to movements of the throttle pedal and the engine can even hold back or stall.

A 'Check Engine' light (engine failure light) can also be an indication of a defective throttle body. Reading out fault codes can provide further detailed information that indicates a defect inside the throttle body. For example, there are several error codes that we often see coming back to certain throttle bodies. An example of this are the error codes DF079 and P0638 that often occur in the Renault - Pierburg / Aisam (8712) throttle body. These error codes indicate problems with the throttle valve control.

Furthermore, the failure of the cruise control may also indicate a defective throttle body.

used throttle body

Possible causes of a malfunction

The above mentioned symptoms have of course an underlying cause. One of the main causes of a malfunctioning throttle body is internal contamination. Due to the contamination accumulated in the throttle body, the throttle valve can no longer move properly, causing problems with the control of the air supply.

Another cause for a malfunctioning throttle body is the presence of one or more vacuum leaks. This causes 'false air' to be sucked in, so that the total amount of air sucked in does not correspond to the position of the throttle valve.

An incorrectly adjusted throttle position sensor can also cause an engine to run badly. 

Remanufacture by ACtronics

Do you have a malfunctioning throttle body that you would like to have overhauled? Take a look at our complete overview of the throttle bodies that we have to overhaul. There is a good chance that you will find the desired type of throttle body with us within a few clicks. For more information about our products, please feel free to contact us! Please note: we only work with car companies and garages!