A knock sensor is a device that can detect out-of-the-ordinary sounds or vibrations in an engine block and signals the engine control unit to determine if something is wrong.

If something is amiss in your engine, you’ll want to know about it as soon as possible to avoid any engine damage. Thankfully, modern cars have problem-detecting technology built-in, the knock sensor among them.

To help you better understand what this car component does and what it means if it’s faulty, the

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for car owners,

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, has created this guide on the knock sensor. We’ll cover what an engine knock is and what causes it, what the knock sensor does and how it operates, and how you can get the best deal on your

car insurance

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What is an engine knock?

First of all, what is an engine knock? An engine knock is essentially what it sounds like—a knocking sound or pinging sound—coming from your engine. Knocks happen due to a reaction in your engine block from pressurized fuel and air igniting in front of the spark plug. It’s basically an unplanned ignition.

Engine knocks can wreak havoc on your engine, so if you notice one or multiple happening, it’s a good idea to get your vehicle looked at by a professional mechanic as soon as you can.

What causes engine knock?

It’s never a good sign when your engine knocks, and identifying the problem isn’t the most straightforward process. There are a few things that could be the cause:

Incorrect timing of a spark plug ignition. In this case, you or a certified mechanic will need to correct the ignition timing.

Deposit build-up in the cylinder from any dirt or debris that made its way in and will require cleaning.

Faulty or damaged

spark plugs

that require a spark plug replacement.

Whatever the cause, it’s important to get it taken care of right away or risk severe damage to your engine.

MORE:

What does the check engine light mean?

What is a knock sensor?

Now that we’re familiar with what an engine knock is, we can discuss the knock sensor.

A knock sensor is a sensing device that detects irregular noises or vibrations in your engine block, such as an engine knock.

The knock sensor in your vehicle can typically be found on the cylinder, the engine block, or the intake manifold. It will signal your car’s engine control unit to determine if there is an issue in engine timing, if the check engine light needs to come on, or if your engine should lose power for safety.

MORE:

Car shaking or vibrating inspection cost

How does a knock sensor work?

Okay, but how does a knock sensor work? Knock sensors are usually constructed from piezoelectric materials that take vibrations and changes in pressure and turn them into electrical signals.

The knock sensor will detect out-of-place vibrations or increased cylinder pressure and send that information to the engine control unit, which controls the fuel entry into your engine and the timing of the ignition. If there is something wrong, your engine control unit will act to alert you to the problem or reduce your engine’s power.

MORE:

Does insurance cover engine failures?

Is it safe to drive with a faulty knock sensor?

Driving with a faulty knock sensor isn’t the biggest risk, but it will cause you to lose engine power and fuel mileage.

The effects of a faulty knock sensor will be most noticeable during acceleration, especially at higher speeds. Your vehicle may not be able to speed up properly, so this could be dangerous if you’re trying to get up to speed to merge onto a busy highway.

Essentially, a faulty knock sensor will cause the engine control unit to decrease power to your engine until it is fixed or replaced. If this happens while you’re driving, you will likely be able to keep driving until you can safely pull over, but do so as soon as possible to avoid your engine shutting down completely.

MORE:

What to do if your engine hesitates during acceleration

How to find affordable car insurance

Engine repairs and, heaven forbid, engine replacements can get expensive, and sometimes the cause of the damage is something out of our control. Start a car emergency fund to back you up in case of a damaging engine knock by saving big on your

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rates with super app Jerry!

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And to ensure you always have the lowest rate, Jerry will send you new quotes every time your policy comes up for renewal, so you’re always getting the coverage you want at the best price. This level of service is why Jerry earned a 4.6/5 rating on the App Store and made it the top insurance app in the country.

“
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blew my mind, honestly. From start to finish, using the app took me 10 minutes and I ended up with $100 of savings a month. Best of all, customer service answered all my questions about rental car reimbursement and roadside assistance.” —Savanna R.

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