[andyz0]

Hi,
New to this forum but tried my luck on Bimmerfest for a while but didn't have much success there compared to other forums so hopefully the UK one will be better!

I had a red runflat warning light come on a month or so ago. I stopped and checked pressured and all were fine. It has remained on ever since, even after resetting (key in and ignition on). The light re-ignites even if not moving the car or wheel (odd, as it's ABS based, not in-wheel sensors).

My car is under third party warranty from the garage I got it from. They will replace most things if they are faulty (not worn), but need to be 100% before agreeing any claim. Car has done ~105k miles.

So far I have tried:
1) Changing wheels (all of them)
2) Over inflating by 5psi
3) Returning to normal pressure
4) Plugging my own OBDII in (no faults detected)
5) Checking battery voltage (12.44v on a decent multimeter when left overnight)
6) Checking tyre pressures (obviously)
7) Taking it to an indipendent BMW specialist. They charge £70 an hour and I can recover £50 an hour. They could not diagnose it fully, so the warranty company are unwilling to proceed with any repair. The garage advised me to take to the dealership and diagnose there. As I can only claim £50 diagnosis, I am at minimum out of pocket £120 as of Friday, IF they diagnose within the hour (£140 p/h after that!).

The indipendent specialist managed to get these faults, after many attempts as they had trouble communicating with the ECU (makes me think it's ECU or communications related).

D35A Communication Gateway Fault
5DF4 Battery Voltage Low
D373 Steering Wheel Column Fault
5DFO Pump Motor Relay Fault
5D93 Front Left Wheel Sensor Faulty
5DA3 Front Right Wheel Sensor Faulty
???? Rear Right Wheel Sensor Faulty

After clearing the faults, they came back, and also an ABS fault, then after a few more clearances the ABS fault went away again and I was back to square 1 (would rather have a runflat fault than ABS!). I have tried 'testing' the ABS the usual way of just stamping the brakes and the ABS works fine.

Any thoughts guys? I can't just ignore the warning if I plan to sell it at some point, so might as well fix while under warranty (and it's annoying, though I have kinda got used to it)

It's going to the dealer on Friday but any ideas before then would be really appreciated, as they are charging £100 p/h for first hour and £140 p/h thereafter which I really can't afford!!!

Last thing to point out is that it is making a worn bearing sound but did this for the past 10k miles (before this fault) and is probably not related (see other post!).

Thanks in advance!
Andy

[N8N]

battery voltage low is the first thing I would address... can cause all sorts of other "non-faults" I have heard...

[GoRomeo]

Originally Posted by N8N

battery voltage low is the first thing I would address... can cause all sorts of other "non-faults" I have heard...

This...

I bet your REST feature is not working either. Once you start having a low battery you start getting ramdom dashboard lights and loss of features. ECU does this to save all the power possible to be able to start your car.

Do a load test on your battery even though voltage shows ok.

[andyz0]

Ummm... Took it to the BMW dealership, they reset the fault codes and reset the warning light and it's gone. Good news for me, but seems odd as I think it was an ECU glitch. Will check the load test if it happens again. Cheers