Tips and Tricks

How to know if a throttle position sensor is bad?

The throttle position sensor (TPS) is a component of the fuel management system. It gives signals to the fuel injection system about the power needs being indicated by the engine and delivers the right mixture of the air and fuel to the engine.

Its signal is continuously combined with other data like engine RPM and air temperature to decide the amount of fuel that needs to be injected into the engine at any given point of time. It is only when the TPS is operating well, that your baby accelerates smoothly and cruises while giving you the best fuel efficiency.

How to detect if something isn’t right?

There are several reasons why your TPS might not function properly. In most of these cases, it will drastically bring down your fuel efficiency.

To ensure safety, most of the manufacturers equip the vehicle with a ‘limp home’ mode with reduced power so that, in the case of a failure, a motorist can safely get off a busy highway. Moreover, even if it begins to fail partially, you will have to get it replaced immediately.

Common symptoms of a faulty TPS:

  1. Acceleration Problem:

If your car is not accelerating, is weak when doing so or accelerates all by itself, then something is wrong with your TPS. Most of the time you will feel that car is not accelerating like it should. All these symptoms point out to a bad TPS.

Acceleration problem

  1. Engine Problems:

If you suddenly start noticing misfires of the engine, the engine stalls suddenly or rough idle, then you must be careful as it means that there is a problem with your throttle position sensor. Don’t be lazy in getting it checked out by a well-trained mechanic as soon as possible.

  1. The car accelerates at low speed:

Sometimes, you will notice that even though your car is accelerating, it is not going beyond a low speed and this also indicates a faulty TPS in your vehicle. This means that your TPS is incorrectly minimizing the power that is needed through the accelerator pedal foot. In this case, your car will not go beyond the speed of 20-30 MPH even though it will accelerate. So acceleration happens at a restricted speed limit. This problem is often accompanied by loss of power too.

  1. The ‘check engine’ light turns on along with any of the above-specified problems:

If there is a problem with your TPS, the Check Engine might turn on to indicate this problem to you. However, this may not happen all the time. If you notice even one of the above-mentioned problems, then you must get it checked by a good mechanic. Any of the above problems can lead to serious safety hazards. The delaying is a huge risk that you just don’t want to take.

Engine problem


It is the throttle position sensor that gives you a better fuel economy and efficiency in any driving condition. So a problem in your TPS is not something that you should take lightly.

Once you realize that your throttle position sensor is not working correctly, you will have to replace. Also, it involves erasing all the faulty codes and software re-programming of the new one. Don’t attempt to do this yourself and always go to a highly trained engineer who will make the right diagnosis and find you the best replacement as well.

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