C30 Electrical Issues

Sounds familiar! I had a similar problem with my BMW 3 series. It drove me nuts for ages! Same symptoms: random error messages and the car struggling to start, especially in cold weather. I'd check all the connections to both the main and auxiliary batteries first. A loose connection can cause a voltage drop and mess everything up. Is your battery light on?

Thanks! Good shout about checking all connections, I'll take a look this weekend. The battery light itself isn't constantly on, but it flickered a couple of times when the engine almost stalled. Did you manage to solve your problem?

Yeah, in the end, it turned out to be a faulty auxiliary battery that wasn't holding charge. It was causing all sorts of weird power management issues. Given your symptoms and the error code, I'd say it's highly likely that's your culprit too. Honestly, I'd recommend getting it checked by a workshop. They will test the charging circuit of the car.

Thanks for the advice! You were spot on. I took it to a workshop, and it was indeed the auxiliary battery. Needed replacing, and with labor and parts, it came to 290€. Annoying, but at least the car is running perfectly again.