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gerhardschmid6

GLC Hybrid Engine Power Loss and ECU Issues

My 2022 Mercedes GLC hybrid with 162105 km is having engine power reduction issues. The error memory shows a defective engine control unit. The mechanic suspects a faulty main relay is causing the ECU problems. Has anyone else experienced similar automotive electronics or engine control issues?

4 comment(s)

erikguenther49

Whoa, sounds familiar! I have a GLC too, and I had something similar happen a while back. Reduced engine power and error codes galore. Could be the main relay, like your mechanic said. Did they check that specifically? If it is the ECU, that's not great, but sometimes it's something simpler messing with it.

gerhardschmid6 (Author)

So, when you had this issue, was it definitely the main relay, or was the engine control unit actually damaged? And did you notice any other weird symptoms besides the power loss? I am trying to understand how the main relay could affect the ECU.

erikguenther49

Okay, so I'm not 100% sure about the actual damage to the engine control unit itself, but the workshop guys told me the relay was the culprit. They replaced it, cleared the codes, and everything went back to normal. I'd suggest letting them take a closer look at the relay before jumping to conclusions about needing a new ECU. Good luck!

gerhardschmid6 (Author)

Just wanted to let you know the main relay was the issue, like you and the mechanic suspected. Got it replaced, and the engine is running smoothly again. Cost me about 120€, which is a huge relief compared to what a new engine control unit would have cost. Thanks a ton for the advice; you really helped me avoid a much bigger problem!

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