Throttle valve defective? You should pay attention to this now!

Reading time 4 Min.

Is the throttle valve on the engine broken? What are the symptoms, how is the replacement/cleaning done and what is the cost? The most important facts are in this article at a glance! at petrol engines (Otto engines), the throttle valve regulates the amount of fresh air that enters the combustion chamber. Diesel engines, on the other hand, are operated with an excess of air and therefore do not need a throttle valve, but often have one flap. Age and dirt can cause the throttle body to become stuck or even fail. However, it does not necessarily have to be replaced with a new part. One Cleaning by a specialist is often sufficient.

Symptoms/signs of defective throttle body

• Fluctuations in engine speed when idling
• Only very slow drop in engine speed after releasing the accelerator pedal.
• Engine power limited.
• The engine doesn'tstart.
• Engine goes into limp home mode.
• Error memory entry like "Throttle position implausible" respectively "Correlation of gas pedal position and throttle valve position implausible"

Clean or replace the throttle body!

If any of the above symptoms appear, it does not necessarily mean that the throttle body has failed. In many cases a clogged throttle body the cause of the associated symptoms. Deposits due to exhaust gas recirculation or crankcase ventilation can be the cause. But also a heavily soiled or defective one Air Filter can cause problems in the intake system. The cleaning (not with the air filter, which has to be replaced when it is dirty) is in many cases a cost-effective alternative to replacement. In the event of a defect potentiometer (position sensor) or another mechanical error, cleaning is usually not possible and there is no other option than replacing the throttle.

In order to clean or replace the throttle valve, it must first be removed. It is located in the intake system of the engine. In order to gain access to the throttle body, the Engine cover, Suction and any other parts removed. The plug can be removed and the throttle valve can be removed. For cleaning, however, a special cleaner be used. The cleaned throttle valve or a suitable new part / exchange part can then be installed again. In many cases, the new or cleaned throttle valve still has to be taught and programmed. The basic setting of the throttle valve is then compared with the control unit. Tip: Depending on the vehicle, the removal is during the cleaning not always required.

Cost of cleaning or replacing the throttle body.

Removing and installing a throttle body typically takes between 30 minutes and 2 hours. The exact effort depends in particular on the installation location and the vehicle type. The material costs for a new throttle valve are usually between 50 and 400 euros. Well-known manufacturers include Mapco, Herth+Buss, Valeo and Magneti Marelli. If the throttle body only needs to be cleaned, you can count on costs between 60 and 200 euros, depending on the effort involved in removing and installing it.

The importance of the throttle valve

The throttle body is located in the air intake system between the air filter and the intake manifold. It enables the engine control unit to regulate the fuel-air mixture. In short, the throttle is a circular plate connected to a pivot that opens or closes the intake port. The mechanical throttle valve, which is connected directly to the gas pedal via a Bowden cable, has long since been replaced by the electric throttle valve. The throttle valve position is varied via a servomotor in the engine control unit (electronic gas). Depending on various parameters such as the accelerator pedal position or the engine temperature more or less fresh air is supplied to the engine. The fresh air is often supplemented by exhaust gases from the exhaust gas recirculation.

The following note is essential: For safety reasons, tuningblog recommends all repair, inspection and maintenance work exclusively to be carried out in a specialist workshop! Although our information is summarized to the best of our knowledge and belief, we cannot assume any liability for the content. All information is therefore "without guarantee".

Of course, that wasn't the end of it!

In this tuningblog category there are guides and instructions for common defects/repairs on the vehicle and for installing accessories/tuning parts. Our articles explain in a simple way common defects and the corresponding repairs, as well as explaining how the first signs of a defect become noticeable. In most cases, we also have initial clues to the repair instructions in our repair instructions approximate The costs of the pending repair are listed. The goal of our subcategory “Auto Repair Guide“ is to create a head start in knowledge for the next visit to the workshop with initial tips. This may save you from tedious troubleshooting and small things can perhaps be done directly on your own. The same applies, of course, to the installation of accessories/tuning parts. Here, too, we would like to help with the implementation with instructions and tips. There are many other posts on this as well. Below is an excerpt of the last and HERE there are all previous instructions:

Suspension spring / broken spring: everything you need to know about repairs!

A tire repair kit instead of a spare wheel?

Symptoms, exchange/repair, costs: defective brake light switch!

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