Is it Safe to Drive With a Faulty Knock Sensor?

Schedule Brake Pad Replacement
Service Area

$124.62 - $450.29

Price range for all vehicles
Average rating from 10,852 customers who received a Brake Pads Replacement.

A car knock sensor is located on the intake manifold, cylinder, or engine block. The purpose of the knock sensor is to sense unusual pulsations caused by the engine detonation. It is basically the computer’s ear to the engine to determine if it is working properly.

To get a better understanding of how a faulty knock sensor reacts, note the points below:

  • One symptom of a bad knock sensor is the engine doesn’t feel right while driving at speed, or while the vehicle is carrying a light or heavy load. If you notice something seems off with your vehicle, even if no light illuminates, it is best to have your car checked out by a mechanic.

  • A bad knock sensor may also not let the engine accelerate properly while driving on the highway, and cause the vehicle to lose fuel mileage. If you notice these things happening, you should have a certified mechanic from YourMechanic inspect why the car is slow to accelerate.

  • The computer in the vehicle’s control system can detect the different sounds in the car’s engine. If the computer doesn’t recognize a sound, it will illuminate the Check Engine Light. This is true for the knock sensor as well. If the knock sensor detects an abnormality, the computer will let you know with the Check Engine Light. If the Check Engine Light turns on, have a certified mechanic inspect your vehicle as soon as possible.

  • Once the computer realizes the knock sensor is not working properly, your vehicle will most likely lose power. How much power you will lose depends on the octane limit of the engine, and how heavily it relies on the knock sensor input. The vehicles that will lose the most power are high-compression and flex-fuel engines. This is because the loss of power will slow the timing and keep the transmission out of drive until the sensor has been replaced. The slow timing is designed to allow you to get to safety or get the vehicle fixed, but not allow you to go very far.

The knock sensor senses the vibrations of the engine and will decrease acceleration until the sensor is replaced. With a faulty sensor, there is a chance that higher emissions are being produced from the engine because the engine may run hot. The Environmental Protection Agency does not allow such high emissions from a vehicle, which is why the decreased acceleration safety feature is put in place.


Next Step

Schedule Brake Pad Replacement

The most popular service booked by readers of this article is Brake Pad Replacement. Yourmechanic’s technicians bring the dealership to you by performing this job at your home or office 7 days a week between 7AM-9PM. We currently cover over 10k cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Brake Pad Replacement reviews

Excellent Rating


YourMechanic Brake Pad Replacement Service

Average Rating

4.9/5

Number of Reviews

10,852

Rating Summary
10,343
326
67
33
83
10,343
326
67
33
83

Eladio

8 years of experience
127 reviews
Eladio
8 years of experience
Honda Civic - Brake Pads Replacement (Rear) - Greensboro, North Carolina
Eladio arrived at the scheduled time and was great to work with. He was very professional and I am very satisfied with his work. This was my first time using YourMechanic and I am very pleased with how easy and convenient this service has been from start to finish. Definitely would recommend.
Nissan Altima - Brake Pads Replacement (Front) - Greensboro, North Carolina
Eladio was on time, expedient, and very professional. Very pleased with provided service (brake shoes replacement).

Willie

22 years of experience
7 reviews
Willie
22 years of experience
Dodge Avenger - Brake Pads Replacement (Front) - Long Beach, California
Willie is an amazing mechanic and person. He was very professional, helpful, knowledgeable and personable. I really appreciated all of his help!!

Richard

15 years of experience
52 reviews
Richard
15 years of experience
Mercedes-Benz C300 - Brake Pads Replacement (Front, Rear) - Pleasanton, California
Richard is very knowledgeable , he was prompt on arrival, change out of pads on my 2014 C300, was well done, and clean up was great. I would highly recommend Richard.

Simon

25 years of experience
16 reviews
Simon
25 years of experience
Infiniti G37 - Brake Pads Replacement (Front, Rear) - Upper Marlboro, Maryland
Simons was GREAT! Very easy to talk to and very knowledgeable on car repair. I hope to use him again very soon.

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE