Peugeot 308 Electric High Voltage Error

Whoa, that sounds like a major headache! A high-voltage system error on a relatively new electric 308 is definitely not something you want to ignore. The engine shutting off and reduced power are serious symptoms. Since you've already checked the obvious stuff like connections, I'd be hesitant to poke around too much yourself. Has the battery warning light come on at all besides the error message? Do you have any way to check the battery voltage, even roughly? It could be a faulty voltage sensor giving false readings, or worse, an actual issue with the inverter. Does it happen more when the car's been sitting, or during/after charging?

Thanks for the quick response! The battery warning light illuminates with the error message. I don't have a way to check the battery voltage. How likely is this a voltage sensor issue versus something more serious like the inverter? If the battery is heavily discharged or defective, would that trigger this error code even if the car is plugged in?

Okay, the battery warning light coming on solidifies that you have a problem that needs professional attention. It could be "just" a faulty sensor, but honestly, with those symptoms I'd lean towards a more significant battery issue. A heavily discharged or defective battery absolutely can trigger that error code, even when plugged in! The car's computer is constantly monitoring the battery's health and performance, and if it detects something out of spec, it'll throw a code. I’d consider taking your Peugeot to a qualified workshop. Do you have a trusted one already? It's likely going to be 290€ to replace the battery, but confirm this beforehand. Don’t risk further damage or even injury by trying to fix this on your own.

Thanks for your insights! I brought the car to the workshop. As you suspected, the diagnostic pointed to a heavily discharged/defective battery. The repair cost was 290€. All seems to be working now. Thanks again for your help!