BlackRider
Mercedes CLA Hybrid High Voltage System Error
Summary of the thread
A 2021 Mercedes CLA hybrid is experiencing a high-voltage system error, causing the engine to cut out and lose power. The issue may stem from a battery drain, defective battery pack, cable damage, or a faulty voltage sensor. After checking the 12V battery, the problem was identified as a faulty voltage sensor, which was repaired at a certified workshop.
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4 comment(s)
BlackRider (community.author)
Good point about the 12V battery. I did check it, and it seemed okay, but maybe I need to load test it properly. It is definitely something to consider. But wouldn't a dead 12V battery present different symptoms? What was the fix in your case? Was it a straightforward battery replacement?
gerteagle4
Mine ended up being a faulty voltage sensor throwing off the whole system. Cost me to diagnose. Of course, a heavily discharged or defective high-voltage battery can absolutely trigger the same error, so it's best to get it checked out by a pro. I wouldn't mess with the high-voltage system yourself. Seriously, are you sure you want to risk that?
BlackRider (community.author)
Thanks for the insights. I took it to a certified workshop. They found a faulty voltage sensor, just like you suggested. Repair including the part and labor came to around 290€ Appreciate the help!
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MERCEDES
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CLA
gerteagle4
Sounds like a headache! I had a similar issue with my CLA, not sure of the exact year. High-voltage system warnings are never fun. Did you check the 12V battery first? Sometimes a weak auxiliary battery can cause all sorts of weird electrical gremlins in these complex systems. Is the car still under warranty?