Urm, help…

[Sladester100]

Urmmm

So this flashed up (with the obligatory BMW bling) the other evening. It was just after a small spirited acceleration but just as I was easing off towards a junction, as I came to a stop the message cleared and could not be found in the check control messages.

The app however pinged up a couple of hours later as per the other pic.
And the next day I received two phone calls from “BMW Proactive Customer Care” one of which advising that if I need recovery to call roadside assistance and quote ‘proactive care’….

Soo anyone else had?

Help!

The car is out of warranty so my immediate concern was “s**t how much is this going to cost me”
But
The car has driven fine both for the rest of that journey and to and from work once since and message hasn’t reappeared…

[paddy wright]

hope that’s not a dear do for you

[ori]

That’s a potentially expensive replacement of the rear diff. Could just be a sensor error though and hence it hasn’t come back?

Any noises?

How far out of warranty are you and what’s the mileage?

[Sladester100]

22,000 miles! Nothing!

It’s 47 months old so 11 months over the standard 3 years.
No noise, no whine, no performance or drive issue that I’ve felt

[Nanu]

Even if out of warranty, unless you have done very excessive mileage, something like a diff shouldn't need replacing.

Sounds more like a sensor issue but if not, then the cost should be met by BMW

[Sladester100]

Even if out of warranty, unless you have done very excessive mileage, something like a diff shouldn't need replacing.

Sounds more like a sensor issue but if not, then the cost should be met by BMW

Yeah I was thinking that surely even out of warranty a part such as this shouldn’t fail!!

I was this evening reminded that it may have popped up once before back in August for a split second mid drive through Devon and Cornwall (I didn’t see it, I was concentrating on the straight through of an S curve on the B road we were travelling!) now he’s seen this pic he thinks that what it was but it disappeared a second later without need for acknowledgement - so potentially a sensor I guess.

[ori]

So you need to plug it into a code reader. I’m thinking a fault like that would be recorded and it will identify a sensor issue for you.

Fingers crossed for you.

Ps. I always take out a warranty. That’s my choice though, but I do recommend it as bmw don’t charge a fortune for it.

[matsmith749]

I did a diagnostic on the car earlier today at a car-meet - lots of codes!

Many intermittents & likely unrelated, but the big drivetrain fault was that the flexray bus was not communicating front / rear modules (permanent failure).

I'm not a mechanic - but the code reader suggests this is normally due to a wiring fault upstream of the modules - typically a bad ground to the chassis.

HOWEVER

Battery voltage was suspiciously low throughout the diagnostic - maxing out at 12.1v. I would have expected more like 12.7v just after the car had been driven for a while - so I strongly suspect a bad battery is at play here & that needs looking at first.

12.1v after a decent run is something like 30% charged..... that's not a healthy battery!

Given the 20+ other intermittent faults that mentioned voltage out of range, my gut feeling is failed battery.

So my suggestion is get that checked properly, and replaced if it is bad. It's a cheapo fix at about £100.

Other faults may well 'go away' once this is resolved.

[Sladester100]

I did a diagnostic on the car earlier today at a car-meet - lots of codes!

Many intermittents & likely unrelated, but the big drivetrain fault was that the flexray bus was not communicating front / rear modules (permanent failure).

I'm not a mechanic - but the code reader suggests this is normally due to a wiring fault upstream of the modules - typically a bad ground to the chassis.

HOWEVER

Battery voltage was suspiciously low throughout the diagnostic - maxing out at 12.1v. I would have expected more like 12.7v just after the car had been driven for a while - so I strongly suspect a bad battery is at play here & that needs looking at first.

12.1v after a decent run is something like 30% charged..... that's not a healthy battery!

Given the 20+ other intermittent faults that mentioned voltage out of range, my gut feeling is failed battery.

So my suggestion is get that checked properly, and replaced if it is bad. It's a cheapo fix at about £100.

Other faults may well 'go away' once this is resolved.

Thanks Mat!

Was good to chat and your E89 35is looked gleaming in the sun!

Thanks for the write up this afternoon. Much appreciated!
Prior to this morning the car was parked up for 48 hours or so as was using my other one but was a good 45 minute drive this morning prior to getting to The Black Swan so I’m supposed about the voltage too.

If it was more drive train / diff lock I’d have expected more errors (and physical feedback, albeit I am also no mechanics!) so this has reassured me a bit

[matsmith749]

45 mins is enough to fully charge an almost flat battery, so I’m pretty sure that needs attention.

Healthy battery only drops something like 2% a day due to parasitic loads.

All those errors mentioning voltage are the classic symptoms.

Keep us informed how you get on, good luck!

[matsmith749]

Been a while - did you get this sorted?

[ori]

Was wondering if we can have an update on this?
Was it just a battery? I think the battery has a 5 year warranty though?

[Sladester100]

Hello!

So no I actually didn’t get an answer.
It stopped doing it for a bit, and then due to some work and home commitments I actually stopped used the Z for a good few weeks (no issues when starting her up again at all).

45 mins is enough to fully charge an almost flat battery, so I’m pretty sure that needs attention.
Healthy battery only drops something like 2% a day due to parasitic loads.
All those errors mentioning voltage are the classic symptoms.
Keep us informed how you get on, good luck!

Yeah at the time I was using daily so I’d expect the battery to be fully charged!

Was wondering if we can have an update on this?
Was it just a battery? I think the battery has a 5 year warranty though?

Interesting the warranty on the battery you say is 5 years?

The error popped up the other day during a long drive (like had done 50-60 miles of motorway driving) prompting a call from BMW Proactive customer care team who asked if I was having any drive issues or not. Again I was not, no change at all, but interestingly it was after I had had a short spirited section using sports plus where the majority of that journey prior was comfort… :/ so now I’m worrying a bit about the actual diff and not just a battery and sensor issue!

I’ll have to go and get it booked in somewhere, I’m literally in the middle of sorting my extended warranty tho so I think I’m tempted to wait and see if it comes up again after that is done!

[Sladester100]

So

This is ongoing.

I know right. Still!!

I will give you a nice ok update later this week but for now - a technical question.

Would a “buckle” or flat spot on the front near side wheel - that is causing no feedback on suspension or steering (I didn’t know it was there until they told me and sent a video) affect the rear diff sensors on a rear wheel drive car.
Like I know on a FWD obvs it would as it will have rotation sensors on each corner to look for slip

But in a RWD?

[B21]

So

This is ongoing.

I know right. Still!!

I will give you a nice ok update later this week but for now - a technical question.

Would a “buckle” or flat spot on the front near side wheel - that is causing no feedback on suspension or steering (I didn’t know it was there until they told me and sent a video) affect the rear diff sensors on a rear wheel drive car.
Like I know on a FWD obvs it would as it will have rotation sensors on each corner to look for slip

But in a RWD?

Possible..is the plated diff wearig out..?