You’re thrumming along a long nation road, of course, and also you can’t really tell what’s going ~ above in her engine bay. That’s since everything is for this reason quiet nowadays.

You are watching: Can a bad knock sensor cause rough idle

But you do see a examine engine light the wasn’t there before or possibly you feeling a weird bumping sound upon acceleration. Maybe your mileage has actually gone downhill fast, or something simply doesn’t feeling right. While the problem can be a selection of things, a bad knock sensor can be the culprit.

What is a hit Sensor?


The final symptom that a bad knock sensor is in my opinion the coolest, and I’m completely geeking out around it. When your knock sensor go bad, your car will effectively slow under the timing just enough to not do any further damages to the car, yet enough therefore you’ll have the ability to get to a mechanic.

Another exciting bit is if you have an EcoBoost, high compression motor prefer Mazda’s SkyActiv tech, or flex-fuel engine, you’ll experience more of an impact when the hit sensor goes bad.

Knock Sensor instead of Cost

For an median vehicle, the cost of replacing her knock sensor in ~ a shop is anywhere from $120-$500. This is made up of parts that will typically cost in between $65 and $200, and the labor, which will selection between $55 and $300.

Replacement Process

If you have some mechanically experience and also want to perform it yourself, just factor in one hour or 2 of your very own time to replace that pesky sensor. YouTube is often a large help as well.

First, take a ton of pictures with your phone for this reason you have actually a reference for what things are supposed to look at like once all placed together. Make certain you disconnect the battery and also get various other hoses, wires, and also brackets out of her way. You’ll give thanks to yourself later.

Then, make certain you get the instead of sensor an initial and discover where your damaged one is. This could seem stupid, but make sure you gained the right component and the it at the very least looks right. I can’t tell you how many times i have picked up the wrong component and it to be a full crapshoot from over there on in.

Once you’ve replaced the sensor, inspect out that photo you took earlier, and put every the bits earlier in place. Now, reconnect her battery and start your auto to watch if that CEL has actually gone away.

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What causes a hit Sensor to walk Bad?

Generally, the hit sensor will certainly go negative with not correct handling. Probably you’re working on the car and bump it with a wrench.

Or, you disconnect and also reconnect it v the battery connected and you fried food it. Simply be mindful with this sensors, and also they must last the life the the engine.

Can ns Drive through a poor Knock Sensor?

You can technically drive v a poor knock sensor, yet depending on exactly how much her motor depends on it, you i will not ~ get really far and also you’ll burn a ton that gas.

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When the hit sensor go bad, that is an extremely important the you obtain it replaced. This is because it is dangerous to run your motor through a faulty knock sensor and in certain cases, the could an outcome in you no finding out a catastrophic engine failure rapid enough. Climate you have a totaled car.