Hi David S, apologies for late reply only just seen your post. Yep finally sorted the problem but took a long time to resolve, in fact didn’t finally resolve it until the end of Feb. BMW offered no help whatsoever other than telling me to take it to a main dealer and depending on what they find they might offer some assistance…. and clearly having resolved it, it’s demonstrated to be a BMW quality issue. I just wasn’t prepared to take it to a dealer with their labour rates in the hope that BMW might make a contribution.
To finally sort the problem, I had to replace the Alternator/Generator/Starter combined component which was defective. Replacement cost at my local independent was just shy of £2k parts and labour.
Problem was to get to that point I had to eliminate the 48v battery being defective. Cost of that was probably going be about £1200 plus fitting, pretty fiddly as it’s connected to the coolant system. I managed to find one on eBay for £200 off a pretty new low mileage X5 (so was pretty confident it would be ok) and had it fitted at my independent. No change to the problem, leaving it down to the generator/alternator/starter. Did think about getting one of those from eBay but decided against it.
Having replaced the parts, the car is like new and drove as it always did!
in the period trying to resolve the problem, the issues did get worse. The heated rear view window, heated seats and heated mirrors stopped working (ok now, but not great in the winter….) and the car sounded like a ‘bag of spanner’s’ at idle, well I say idle, it was ‘racing’ rather than idling. I also ensured I kept the normal battery fully topped up as I did experience a complete electrical shutdown whilst out one day as the battery wasn’t being charged correctly due to the generator issue. Thought it was one of the usual shut down episodes, but instead of being a simple ‘push the start button’ fixes, the whole car was dead, luckily I had managed to cruise into a laybye.
When my independent rang bmw parts, they identified that they were getting a lot of enquiries each week for the generator component, so clearly a big problem for BMW.!! Which of course BMW denied when I told them.
Hope this helps and you get it sorted, it might not be the same issue as mine, but I bet it is! My independent has had an X3 in with the same problem since he did mine.
Bit of a heads up, I did struggle to find garages willing to take on the repairs (even so called BMW specialists) so might need a bit of looking for. If you’re pretty handy, it’s probably something you could do yourself but it’s pretty fiddly and takes a bit of time I understand.
Not sure where you’re based, but I still have my original battery if you wanted to eliminate the battery.
If you want any further info just let me know.
It’s something BMW need to wake up to because I can see there being a lot of very unhappy owners around!!
Cheers