Toyota Noah Knock Sensor Issue

I'm at my wit's end with my 2018 Toyota Noah hybrid. The check engine light is constantly on, and I've noticed a significant drop in fuel efficiency. On top of that, the engine idles unevenly, almost like it's misfiring sometimes. I scanned it and it's showing a defective knock sensor. I've checked the wiring and the plug connection seems dodgy. Anyone else run into this?

4 comment(s)

Sounds familiar! I had similar issues with my old Opel Astra – constant check engine light, and the fuel consumption went through the roof. Turned out to be a faulty sensor connection too. What kind of mileage are you getting and is the malfunction indicator always on?

Yeah, the malfunction indicator is always on, super annoying! I'm getting around 9l/100km now, used to be closer to 6. Where was the faulty connection in your Astra? Was it easy to spot?

Mine was corroded right where the sensor plugged in – almost invisible until I gave it a wiggle. Given your mileage and symptoms, it’s likely the same for you. I'd suggest taking it to a workshop if you are not comfortable replacing the wiring yourself.

Thanks for the advice! I took it to the shop, and you were spot on – corroded plug connection to the knock sensor! They replaced the plug, and it cost me 95€. Check engine light is gone, and the engine is running smooth again. Appreciate the help!

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