erikfuchs68
Mercedes CLA knock sensor issue
Summary of the thread
A 2022 Mercedes CLA owner is experiencing issues with a check engine light, increased fuel consumption, and uneven idling. An OBD scan indicates a defective knock sensor, and the owner suspects a faulty cable or plug connection. Another person with a similar experience suggests checking and cleaning the sensor's connector, but ultimately recommends replacing the sensor if cleaning doesn't resolve the issue. The owner decides to consult a mechanic, who confirms the knock sensor is faulty and replaces it, resolving the problem.
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4 comment(s)
erikfuchs68 (community.author)
Thanks for the quick response! The sensor is the original one that came with the car. When you had the problem, were your symptoms exactly the same? And did cleaning the connector solve the issue or did you have to replace the sensor?
alexandertiger3
Yep, check engine, rough idle, the whole shebang. Cleaning the connector didn't do squat for me, unfortunately. Ended up needing a new knock sensor. TBH, with modern cars, it's often better to let a workshop handle it to ensure proper diagnosis and avoid further issues.
erikfuchs68 (community.author)
Okay, thanks for sharing your experience! It sounds like I'm heading down the same road. I'll take it to a trusted mechanic. Your insights have been a great help. I just got it back, the mechanic confirmed it was the knock sensor, they replaced it. The check engine light is off and the car runs smoothly now!
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MERCEDES
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CLA
alexandertiger3
Dude, sounds familiar. I had a similar issue with my CLA a while back. A bad knock sensor can mess with the ignition timing and cause all sorts of headaches. First thing, double-check the sensor's connector, maybe give it a clean with some electrical contact cleaner. Is the sensor itself OEM, or an aftermarket part?