oliverberger10

Mercedes GT Roadster High Voltage Error

I'm starting to lose my mind here. I've got a 2021 Mercedes GT Roadster, hybrid engine, with about 96000 km on it. Recently, I keep getting this annoying "High-voltage system error" message popping up. It's stored in the error memory, which I can read out. What's worse, sometimes the engine just decides to shut off completely, and I get seriously reduced engine power at other times. I suspect it's a battery issue, like maybe it's heavily discharged or even defective. I did a quick check of the electrical wiring and didn't see anything obvious, no cable damage that I could spot. Could a battery drain cause all this? I am not an expert, but I have some knowledge about cars. Any ideas before I take it in and get robbed?

A 2021 Mercedes GT Roadster with a hybrid engine was experiencing a "High-voltage system error" message, engine shutdowns, and reduced power. The initial suspicion was a defective or heavily discharged battery. A suggestion was made to check the 12V battery, which can cause issues with the high-voltage system. Upon testing, the 12V battery was found to be faulty, and replacing it resolved the error and restored normal engine function.

Did this summary help you solve your problem?

4 comment(s)

Sounds familiar. I had a similar problem with my old BMW i3, although it wasn't quite as dramatic. I also got high-voltage system warnings. Is your 12V battery OK? In my case, the small 12V battery was causing all sorts of weird issues with the main high-voltage system. Think of it like a small cog jamming up a big machine.

Interesting! I hadn't really considered the 12V battery. I mean, I assumed it was fine since everything else seems to be working – lights, radio, etc. But if that was the culprit, wouldn't that be something? How did you figure out it was the 12V battery and not something more serious with the main high-voltage system? Did you also have an electrical fault stored?

Well, the i3 is known for that issue. I was getting odd electrical faults and weird behavior. Eventually, the car wouldn't start. A simple battery test showed the 12V was toast. Given your symptoms, it's worth checking. But honestly, with a high-voltage system error, it's probably best to get it properly diagnosed by a workshop. It could be something simple, but it could also be a more serious issue with the hybrid system itself. Don't risk it.

You were spot on. Turns out the 12V battery was indeed the problem. I got it tested, and it failed miserably. Replaced it, and the high-voltage error is gone, engine runs perfectly, and no more power reduction. The whole thing cost me 290€, including the battery and installation. Thanks a bunch for pointing me in the right direction! Saved me a ton of stress and probably a fortune compared to having the main battery replaced.

rmh_community_comment_box_header

community_crosslink_scanner_headline

community_crosslink_scanner_intro

community_crosslink_scanner_title

community_crosslink_scanner_price

community_crosslink_rmh_headline

community_crosslink_rmh_intro

community_crosslink_rmh_title

community_crosslink_rmh_subtitle

community_crosslink_rmh_brand

MERCEDES

community_crosslink_rmh_model

GTROADSTER