Knock Sensor Troubleshooting Questions Answered

Publish date: 2024-06-09

The knock sensor is a vital component to keeping the engine running as it should. Finding solutions to knock sensor problems can be bewildering and Experts are there to provide customized answers to each unique problem. Read below where Experts have answered Hyundai owner’s knock sensor questions.

What is a knock sensor?

This sensor in the engine communicates with the Engine Control Unit (ECU) to retard timing so the ignition in a cylinder takes place at just the right time. Its purpose is to prevent engine knocking yet achieve optimum power and fuel economy from the engine. It responds to the spark knock caused by pre-detonation of the air/fuel mixture.

What is the average cost to replace one on an Accent and where is it located?

The unit costs just over $70 and replacement would require an hour and half of labor. The total cost will vary since local labor rates are prevailing. The illustration below shows its location on that side of the engine closest to the windshield.

Where is it located on a Sonata?

The sketches below illustrate the location:

Will replacing this help with a sporadic engine knock?

Case Details: The Accent runs smoothly otherwise and when oil is added the knock subsides. A local garage has recommended a top overhaul at a cost of $1000.

Replacing the knock sensor would be a good idea and certainly more cost effective; though it might not necessarily be the right solution. Being a far cheaper option, it is worth a try but offers no guarantee of success.

Will a defective knock sensor cause filling the gas tank to take longer?

There is no connection whatsoever between the two. If the knock sensor is faulty the only solution is to replace it. Difficulty in filling gas is probably due to a failed purge solenoid valve.

What do fault codes P0301 and P0325 on an Accent indicate?

With these codes the check engine light should be on as well. P0301 is a misfire code while P0325 relates to the knock sensor. Both codes could be resolved by replacing the spark plugs which are evidently misfiring.

What could cause an Accent with a misfire and knock sensor code to die when the accelerator is pressed?

The fuel pressure needs to be checked as these symptoms point to low fuel pressure. The other possibility could be a clogged exhaust system. This can be checked by having an exhaust back pressure test done at a muffler repair shop which has a back pressure tester.

What could be the problem with an Accent which displays four fault codes, cranks easily but will not start?

Case Details: Error codes set are P0326, P0722, P0134 and P0343.

Here are what the various fault codes refer to:

The easy crank is cause for concern because it does suggest a broken timing belt. This is the first detail which needs to be checked. If the timing belt is good then a diagnostic scan on the cam sensor should be the next step as all symptoms point to a timing issue.

Knock sensor problems are linked to the ignition and extension spark plugs. When problems such as these arise it may be difficult for owner’s to know exactly what is causing the problem. Turning to an Expert for help can save you time and money without having to go to an auto shop. Verified Experts are available online at your convenience to answer all your knock sensor questions.

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