vivieneis1
Mercedes B Klasse Oil Temperature Warning
Summary of the thread
A 2020 Mercedes B Klasse with a gasoline engine and high mileage is experiencing an oil temperature warning light issue. Diagnostics indicated an error related to the engine oil temperature sensor, and the oil pressure warning lamp also lights up intermittently. The problem was suspected to be a faulty oil sensor or a defective cable or plug connection. After inspection and professional evaluation, the issue was confirmed to be a defective cable connection to the oil temperature sensor, which was replaced, resolving the warning light problem.
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4 comment(s)
vivieneis1 (community.author)
Thanks for the tip! I did a visual inspection of the wiring and the plug, and nothing immediately jumped out. No obvious corrosion, but I'll take a closer look. You mentioned it might not be the sensor itself. In your case, with the Opel, was the car's performance affected, or was it just the light? I'm trying to figure out if the oil temperature reading is actually incorrect or if it's just a faulty signal.
rainer_maier1
Well, with the Corsa, the performance seemed normal at first. But after a while, I noticed it was running a little rough, especially on cold starts. I really don't know if that's connected. Honestly, it might be best to get it checked by a professional. They can do more thorough car diagnostics and pinpoint the exact problem. Don't want to risk damaging your engine, right?
vivieneis1 (community.author)
You were right, it turned out to be a faulty connection! Took it to the workshop, and they confirmed the cable to the oil temperature sensor was indeed defective. They replaced the connector, and the warning lights are gone. The error is gone as well. Total cost was 95€ Thanks for pointing me in the right direction!
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MERCEDES
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BKLASSE
rainer_maier1
That sounds familiar. I had a similar issue with my old Opel Corsa, although it wasn't exactly the same. The oil temperature light was going crazy. Did you check the wiring harness connected to the car sensor? In my case, it turned out to be a corroded connector. Could be worth a look before you assume the oil temperature sensor itself is bad. Is the car running any differently, or is it just the warning lights?