[Jimbob335DX]

Hi all, just bought my first 3 series. I have done the usual searches to find previous threads, but alas, nothing obvious comes up.

Never owned a BMW before having had a quite varied ownership. In recent years, all cars have been manual, except for a foray into Audi, where I owned and A6 Black Edition Avant, which had an electronic handbrake. It auto sensed and when stopping, engaged, and pulling away at a hill is a one footed affair. Just stomp the throttle and your away.

So the BMW... a little niggle. Auto, manual hand brake. I arrive at a junction with a hill start requirement, I engage the hand brake, and the car rolls back 3 or 4 inches as I engage the hand brake, when I lift of the foot brake. On Pull away, I release the handbrake and 3 to 4 inches of further roll back. I have tried it 3 or 4 times at the same junction and no amount of pre throttling prevents the roll back.

The next time I approach, I think, no issue, Ill just hold on the foot brake, so then its time to move away, I move my foot from brake to throttle, the car rolls back 3 to 4 inches... which will be the delay of lift to press. Expected I think but makes me look like a complete tool and have no driving skills.

The result is better as I only have the 1 period of roll back, so a 3 or 4 inch drop from where I stopped, in scenario 1 its 9 to 12 inches from the original stop point.

The next time I approach, I make sure I am in sport plus mode, so I have the engine revs to counter the roll back, and I try the left book brake, right foot throttle, and low and behold, 3 to 4 inches of roll back.

Kind of frustrating. I Wondered it had a issue with the auto stop start function, so testing in sport plus eliminated that issue. It still does it.

I have tested it on my drive, which has a slight incline towards the house. Even putting the car just into park from a reverse into the drive, it rolls backwards 3 to 4 inches when I lift my foot off the brake pedal, as though its rolling back into the neutral and the park position. I get the feeling its a kinda auto clutch thing, where the car doesn't quite sense any movement, and acts when it feels there is a roll back. I am pretty sure I would fail the driving test as the roll back is certainly noticeable.

The car is due a service in 1100 miles, is this normal, and just a frustration I have to live with, overcome?... Worth mentioning at the service?

Any experience of similar issue with fellow owners?

Cheers and thanks

[Jeff123]

That sounds exactly like mine and IMO completely normal.

I have had three BMW automatics in a row and all are the same as you describe. If I drive to a very steep hill and hold it on the footbrake, when you go for the accelerator, the car will roll backwards if i am not quick enough.

I rarely use the handbrake at all unless I am parking on an incline.

[doncarlyon]

My 4 series doesnt do this. In drive, on a hill it just stays where it is.

[Abzynthe]

My 4 Series has never rolled back on a hill, maybe it hasn't been steep enough.

[Jeff123]

The hills that I am referring to are steep ones. I live in Yorkshire! On a slight incline the car won't roll backwards, but there is a "tipping point" where the car will just about hold itself and anything steeper than this it will roll backwards.

TBH, I don't know how far it will actually roll as I have never tried it, but I suspect that it will just keep rolling if its on a steep hill.

[thescouselander]

I think it's normal. Most if not all conventional auto boxes will allow the car to roll back if the hill is steep enough. The other issue is that BMW couldn't engineer a handbrake if their lives depended on it - they're all rubbish IMO and that includes the handbrake on my F36 which I only picked up last week.

BTW it's not a good idea to use park in place of the handbrake to hold the car - you can damage the gearbox doing that.

[Harryg]

Originally Posted by Jeff123

The hills that I am referring to are steep ones. I live in Yorkshire! On a slight incline the car won't roll backwards, but there is a "tipping point" where the car will just about hold itself and anything steeper than this it will roll backwards.

TBH, I don't know how far it will actually roll as I have never tried it, but I suspect that it will just keep rolling if its on a steep hill.

This is one thing I miss from my old car MercededC220 that had a hill start assist which is far superior to BMW, it worked by pressing the brake then brakes were locked on even with foot of the brake they released when the accelerator was pressed when driving away and this worked on very steep hills, the BMW works by giving you 3-5 seconds of hold which should hold the car stationary when moving from brake to throttle which as I say is naff compared to Mercedes.
Having said that my 420D doesn't roll back on hills but I hate leaving it in drive when stationary in traffic.

[Hooded]

I've never experienced any roll back on a hill once in Drive on mine.
Stop on hill, right foot on brake pedal, right foot off brake pedal straight onto throttle (takes a second or so), car doesn't roll back at all during this time. Isn't there some kind of hill
Hold assist going on?

Now if I tried taking my foot off the brake on a step enough hill and waiting a few seconds maybe it would roll back, but I haven't tried this out.

[Harryg]

Originally Posted by thescouselander

I think it's normal. Most if not all conventional auto boxes will allow the car to roll back if the hill is steep enough. The other issue is that BMW couldn't engineer a handbrake if their lives depended on it - they're all rubbish IMO and that includes the handbrake on my F36 which I only picked up last week.

BTW it's not a good idea to use park in place of the handbrake to hold the car - you can damage the gearbox doing that.

When I test drove the 420d I remarked how it was poor on hill assist compared to the Merc and guess what, they stated "when you come to a stop just press the park button and this will hold the car then when pulling away drop it back into gear". Would certainly not recommend this at all on an automatic I would be looking for bits coming out of the gearbox.

[thescouselander]

Originally Posted by Harryg

When I test drove the 420d I remarked how it was poor on hill assist compared to the Merc and guess what, they stated "when you come to a stop just press the park button and this will hold the car then when pulling away drop it back into gear". Would certainly not recommend this at all on an automatic I would be looking for bits coming out of the gearbox.

The set up of the auto box does seem to result in a very weak "creep" and I expect this will lead to weak hill holding too. My car won't even move on our gravel drive without giving it some throttle - I've not had to do that in any other car.

[NISFAN]

It takes a pretty steep hill for me to get roll back on a normal (off brake, on accelerator) start with my ZF8 equipped cars.

I have had Mercedes in the past and agree the hill hold assist is much better on those. But you'd expect that as they had to develop a good solution from having a foot operated hand brake

Back to the issue, I would think on really steep hills, you might have to do a two pedal start, left foot on brake, right foot on accelerator, then release brake when you feel the drivetrain loaded up enough to move you forwards.....as you do in a manual car with the handbrake.

[Harryg]

Originally Posted by thescouselander

The set up of the auto box does seem to result in a very weak "creep" and I expect this will lead to weak hill holding too. My car won't even move on our gravel drive without giving it some throttle - I've not had to do that in any other car.

I think its a very fine line as to when drive creep actually kicks in if it was done too quickly I think it would have the same effect as slipping the clutch on a manual car, that is why the 3-5 second hill assist allows for time to hit the throttle when taking your foot off the brake.

[Ridg]

Seams to be quite a divide on this one, from my experience even on a slight incline ~4%+ the hold will kick in.

Stop at junction

Either keep foot on brake or apply hand brake

Lift foot off brake or put car in drive and release hand brake

Car stays where it is until the accelerator is pressed.

[Hooded]

Originally Posted by NISFAN

It takes a pretty steep hill for me to get roll back on a normal (off brake, on accelerator) start with my ZF8 equipped cars.

I have had Mercedes in the past and agree the hill hold assist is much better on those. But you'd expect that as they had to develop a good solution from having a foot operated hand brake

Back to the issue, I would think on really steep hills, you might have to do a two pedal start, left foot on brake, right foot on accelerator, then release brake when you feel the drivetrain loaded up enough to move you forwards.....as you do in a manual car with the handbrake.

However, surely the hill start assist (or whatever BMW call it now) should hold the car in place for a couple of seconds even on a step hill, allowing you to take your right foot off the brake pedal and move it onto the throttle before it releases and the car rolls back.
At least this is how I understand it and it seems to work on my car.

[HighlandPete]

Originally Posted by Jimbob335DX

Any experience of similar issue with fellow owners?

Doesn't appear the Hill-Start Assistant (Drive-off Assistant) is working correctly. Shouldn't be any roll back, as it is the hydraulic braking that is applied with the Assistant function. Gradient shouldn't be an issue.

Or are you delaying the to the point it is 'timed out', to get roll-back?

[HighlandPete]

Originally Posted by Hooded

However, surely the hill start assist (or whatever BMW call it now) should hold the car in place for a couple of seconds even on a step hill, allowing you to take your right foot off the brake pedal and move it onto the throttle before it releases and the car rolls back.
At least this is how I understand it and it seems to work on my car.

Agree, it should hold stationary until either enough torque is applied to overcome the braking force, or is timed out, when it will roll back. BMW say it applies on gradients up to 50%. No one will be driving on inclines at that magnitude.

I tried out the feature in my E91 when I first had it, on the pass to Applecross. Worked perfectly every time, on inclines something like 1:4 - 1:6. Only when 'timed out' I'd see any roll-back.

[Hooded]

Originally Posted by HighlandPete

Doesn't appear the Hill-Start Assistant (Drive-off Assistant) is working correctly. Shouldn't be any roll back, as it is the hydraulic braking that is applied with the Assistant function. Gradient shouldn't be an issue.

Or are you delaying the to the point it is 'timed out', to get roll-back?

Agree, ... could it be a faulty incline sensor on the OP's car?
I'm sure I read once that the hill start assistant kicks in on gradients above a certain percentage (I think it might have been 7%).

[HighlandPete]

Originally Posted by Hooded

Agree, ... could it be a faulty incline sensor on the OP's car?
I'm sure I read once that the hill start assistant kicks in on gradients above a certain percentage (I think it might have been 7%).

I wouldn't initially think so, as Hill-Start assistant is part of the DSC suite. I'd expect a warning for DSC function, if such an important sensor is not commutating correctly.

In a similar topic a while back I posted..

An auto can drift backwards if there is no hill start assistant, or the brake hold feature is not engaged. My 5-series will roll back, if I don't use Autohold.

I remember this subject coming up when running my E91 330d and confirming the function, for another user, by trying it on a couple of different inclines and a steep hill.

On the initial release of the foot brake, the car wouldn't roll back. If I moved forward and then I took my foot off the throttle it would roll back, if I didn't apply the foot brake again.

Maybe it is the way some move off, and/or use of the footbrake.

[Harryg]

I believe this is fitted to manual gearboxes also to give the op sufficient time to take foot of footbrake to finding the biting part of the clutch, it certainly seems as though something is not working as it should.

[999rigger]

Mine certainly HAS got hill hold! It never rolls backwards on hill starts.

[bimmer456]

Mine doesn't roll back or only very slowly.

[Stainy]

I don't need hill hold. I can drive........which includes correct use of handbrake and throttle

/awaits abuse