Hey folks,
Currently struggling to diagnose a weird issue with my F10 M5 2012. The car is totally standard with 82,000 miles. No warranty
What's the issue?
Typical drivetrain malfunction warning on the iDrive, then reduced power. Usually occurs after about 45 minutes of driving. If I then stop the car, turn off, it clears, but then can reoccur much more quickly when I get going again. It can also occur several times in the same journey.
In all other respects the car runs fine. No smoke, no noises. As soon as the fault is cleared by switching off, it's back to it's best.
What codes is it showing?
120408 Boost pressure control: shutdown due to reaction
164022 Inlet camshaft sensor 2, electronic short circuit to positive
120908 Boost pressure control 2, cut-off: pressure build-locked
120918 Boost pressure control 2, shutdown coupling: pressure build-locked
What have I done about it?
I took the car to my local BMW service centre who normally look after the car and, despite a few visits, they were unable to find a cause or solve it. To be honest, I got frustrated by the experience with them and gave up. You know how it is.. you have to talk to the tech via the service guy, so it's all so slow and frustrating.
I've now got it in with a really reputable local BMW specialist and they definitely seem to be trying their best, but they're a bit stumped too. They've replaced the Inlet camshaft sensor, and updated to the very latest engine software (which is the common solution to the mixture of boost control codes).
So far, it's not fixed anything.
How can you help?
The challenge here is that the issue is so hard to recreate. So, the mechanics try something, I pick the car up, spend a few hours driving it to see if it'll reoccur. It eventually does. Take it back to the mechanic and repeat.
It's not their fault - But I don't want to be paying for some guy to drive my car around for hours, so I do that part myself. But, I wondered if anyone has seen this particular set of circumstances and had a strong view on a potential root cause? I'd like to avoid replacing lots of expensive parts as some sick game of whack-a-mole if I can!
If it was something really obvious, I'm convinced that these two sets of mechanics would have found it by now. So.. I'd really appreciate any concrete ideas?
Cheers