What Happens When The Electronic Throttle Control Goes Bad?

Cables are out – computers are in. This is the case for all cars equipped with a computerized throttle controller over a traditional cable system. However, even the magic of technology can eventually run into issues. What happens when an electronic throttle control goes bad?

Rather than moving a cable, ETC uses sensors to inform the ECM of the position of the gas pedal, and when it fails, symptoms can be severe. Some of these include sudden idle surges and engine stalling, an engine light that flashes intermittently, or a massive drop in mileage.

Ignoring a faulty ETC will not only cause your engine performance to suffer but can be a safety hazard as well.

Thankfully, in this article, we’ll cover everything you need to know about an ETC, including what to do if it fails. Let’s start by taking a closer look at what an electronic throttle controller is and how it works.

What Is Electronic Throttle Control?

There are two main types of throttle control systems – cable, which is the older of the two, and electronic.


With a traditional cable system, an internal wire connects the gas pedal and the control linkage on the throttle body housing. A throttle body is a circular valve that regulates the amount of air that’s allowed to enter the combustion chambers.

When you press down the gas pedal, it opens the throttle.


With electronic throttle control, instead of a cable, the pedal is connected to a position sensor. When you press the gas pedal, its position is shared with the ECM, which uses it to open the throttle as efficiently as possible.

One of the great things about an ETC is that it’s easily linked to other systems, like cruise control, engine control, traction control, and ESC control. Basically, it ensures the entire system operates more efficiently.

Signs That Suggest Your Electronic Throttle Controller Has Gone Bad

The throttle positioning sensor (TPS) clearly has a critical job, and if it fails, you’ll likely experience some severe symptoms.

Decreased Fuel Mileage

If your TPS is acting up, it may cause the butterfly valve inside the throttle body to allow too much or too little air through. If this happens, your ECM will likely try to compensate, which can drastically lower your fuel economy.

Acceleration Issues

Imagine if your car suddenly started accelerating for no reason – scary, right? This is one of the possibilities if your TPS fails. It may also result in a lack of power, where you’re able to start the car, but it doesn’t remain running for long.

Sporadic Idling

If your TPS decides to call it quits, you’ll likely experience random idle surges. Alongside sporadic idling, you may also notice your engine misfiring, a rough idle, or stalling. It’s also possible that your car idles too high or too low.

Intermittently Flashing Indicator Light

Your engine is designed to run as efficiently as possible. For this reason, if something isn’t working correctly, it can throw the entire system out of balance. Thankfully, this is the exact purpose of the “check engine” light.

If your TPS goes out, there’s a good chance you get notified randomly by a flashing indicator light.

Here’s What To Do If Your Electronic Throttle Controller Goes Bad

There are many reasons an ETC might act up. However, the most likely issue is that it’s dirty. Thankfully, cleaning an electronic throttle body is pretty simple.

If it has failed completely, though, you may need to replace the throttle body entirely. However, first, you’ll need to test it using a basic multimeter.

Depending on the location of the throttle body, you may be able to replace it yourself without too much hassle.

If you choose to take it to a shop, be ready to spend between $400-$1,500 for both parts and labor on an electronic throttle body replacement. Though, again, much of this depends on the make and model of your vehicle.

Just Because Your Throttle Hesitates Doesn’t Mean You Should

If your electronic throttle controller goes bad, don’t be the one that waits to take care of it. Not only will your engine suffer in terms of performance, but it also poses a potential safety concern due to random acceleration issues.

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Joshua Barrett

Josh Barrett is a writer hailing from the great state of Alaska. While describing himself in the third person is not his forte, writing about any and all things automotive – is. After 13+ years hustling in the exciting world of car sales, he took off to travel the world with his dog Teemo.