[g2artist]

My 335 e93 will jerk forward when I let off the brakes from a stop. I'll be sitting at the light and when I let off the brakes slowly it feels like they suddenly just let go and the car jerks forward. I have an auto transmission. The thing is it will go away when the car warms up. Anyone else seen or heard of this problem? What was done to remedy it?

[bsamoul]

Every E90 has it. It's called brake assist for holding the car on a hill when you take the brakes off, it will hold for a couple of seconds so you can start accelerating.

[MontegoGoGoGo]

I just had to get used to mine and be slower with it. It was hard for me to not scratch my car when backing out of the driveway. I'm getting better now, but at first it would take me 5 minutes just to back out!

[blk335i08]

Originally Posted by bsamoul

Every E90 has it. It's called brake assist for holding the car on a hill when you take the brakes off, it will hold for a couple of seconds so you can start accelerating.

Only MT's have this, autos don't roll backwards because your never in neutral

[bsamoul]

Originally Posted by blk335i08

Only MT's have this, autos don't roll backwards because your never in neutral

Actually, they do have it.

[767jetz]

Originally Posted by blk335i08

Only MT's have this, autos don't roll backwards because your never in neutral

They all have this. My step does the same thing.

[Houman21]

Welcome - After you adjust your driving to the brakes in the car, it will rarely happen

[g2artist]

Originally Posted by bsamoul

Every E90 has it. It's called brake assist for holding the car on a hill when you take the brakes off, it will hold for a couple of seconds so you can start accelerating.

This is not brake assist.....my problem happens when the car is cold and goes away after about 10 minutes of driving. WHEN I'M AT A STOP ON FLAT GROUND, I slowly let my foot off the brake. The car will suddenly jerk forward and start rolling practically giving me whiplash. Feels as if someone is giving me a fender bender from behind everytime I let off the brakes. I cant even get the car to slowly ease forward (as is needed in parrallel parking) by letting off the brakes as slowly as I can. Everytime I let go of the brake even slowly the car JUMPS forward. When the car is warm it wont do it. I can easily let my foot off the brakes slowly and the car will start rolling forward while RIDING the brakes.

[Notorious]

Originally Posted by g2artist

My 335 e93 will jerk forward when I let off the brakes from a stop. I'll be sitting at the light and when I let off the brakes slowly it feels like they suddenly just let go and the car jerks forward. I have an auto transmission. The thing is it will go away when the car warms up. Anyone else seen or heard of this problem? What was done to remedy it?

I created a thread about this exact same problem quite a while ago, here it is: http://www.e90post.com/forums/showth...=sticky+brakes

On page #4 post #77 a member found a potential solution to it, i will be bringing in my car soon hopefully to have it looked at.

I still contend that the symtoms that we are describing are in no way, shape or form a "feature" or "normal" as some have suggested.

[SteveC]

Originally Posted by Notorious

I created a thread about this exact same problem quite a while ago, here it is: http://www.e90post.com/forums/showth...=sticky+brakes

On page #4 post #77 a member found a potential solution to it, i will be bringing in my car soon hopefully to have it looked at.

I still contend that the symtoms that we are describing are in no way, shape or form a "feature" or "normal" as some have suggested.

German cars have an anti-stall feature that in manual cars allows you to take your foot off the clutch with no gas and the car will move slowly but smoothly forward...no pecking duck starts. At the same time cars have an enrichment cycle that increases the amount of fuel when the car is cold. If this anti-stall feature was set up a little too aggressively, you would get exactly what you're talking about. Alternatively, if the engagement of your AT was a little to abrupt when its oil is cold, you'd get the same thing. Either way, this sounds both uncomfortable and abnormal and is something your dealer should be able to rectify. However prepare to be without your car for a few days as prolems related to cold running are more difficult to diagnose, since the car has to be cold to find it (obviously), which limits the time available for diagnosis.
One way to tell whether this is fuel supply or gearbox related would be to warm the car up without driving it then see if the problem is still there. If it persists for the usual time after the engine is warm, its transmission. If warming the engine means the problem is gone as soon as you drive, its related to the fuel injection set up.

[nicknaz]

Originally Posted by SteveC

German cars have an anti-stall feature that in manual cars allows you to take your foot off the clutch with no gas and the car will move slowly but smoothly forward...no pecking duck starts

this 'feature' you are talking about is called 'low end torque' and it is not exclusive to german cars. You are making it sound like a manual transmission E90 will not stall if you don't apply throttle when engaging the clutch from a stop, and this is simply not true

[SteveC]

Originally Posted by Nick Nazareno

this 'feature' you are talking about is called 'low end torque' and it is not exclusive to german cars. You are making it sound like a manual transmission E90 will not stall if you don't apply throttle when engaging the clutch from a stop, and this is simply not true

Take any German car, apply no gas, gently let in the clutch and the car will move off smoothly. You can even change into 2nd and as long as you use the clutch to maintain the idle speed of the engine it will continue to move forward smoothly. German cars will not stall in low gears with your foot off the gas.

Obviously the relationship of engine revs to wheel rotation is fixed, depending on the gear ratio you've selected but as long as your car is not mechanically forced to fall below the engine's idle speed, it will continue to move forward with no gas applied and will not stall.

In Germany, autobahns are hilly and crowded are drivers are often required to creep forward for extended periods. Before moving to Germany I was used to having to apply gas if I wanted to avoid stalling. This was not neccessary on any car I drove in Germany, including some low torque rentals.

In AT, you have to put your foot on the brake to prevent the car moving forward, but similarly, if you take your foot off the brake the car will begin to move forward smoothly and will maintain something like walking speed with engine revs at idle.

[HermesRider]

[RyanDe680]

I had this fixed on my 335i.

Here's the TSB:


I B 24 03 08
Automatic Transmission July 2008
Technical Service

This Service Information bulletin supersedes SI B24 03 08 dated June 2008.

designates changes to this revision

SUBJECT
335i, 535i with N54 and 6HP19TU - Jolt and Delay when Pulling Away

MODEL
E90, E92, E93 (335i) with N54 and 6HP19TU from 12/06 up to 09/07

E60, E61 (535i) with N54 and 6HP19TU from 03/07 up to 03/08

SITUATION
The customer may complain of a delayed engagement and a harsh jolt when accelerating from a stop.

The situation occurs only during the engine warm-up phase (cold engine), and can not be reproduced in the Sport Mode.

CAUSE
EGS software (unfavorable NIC – Neutral Idle Control calibration)

SOLUTION
On a customer complaint basis only, check the vehicle's integration level.

If the integration level is:

* On E9x vehicles – E89X-07-06-520 or lower

* On E6x vehicles - E060-07-09-530 or lower

Reprogram and recode the complete vehicle with a current Progman version (target levels are E89X-07-09-518 or E060-08-03-510, respectively, for E9x and E6x vehicles).

WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.

[blk335i08]

Originally Posted by bsamoul

Actually, they do have it.

Read the post above this comment.

This jolt is NOT caused by brake assist. Please don't post your own opinions, post facts.

MT's only have brake assist. Their is no need for it on an auto because your never sitting in neutral.

[g2artist]

Originally Posted by Notorious

I created a thread about this exact same problem quite a while ago, here it is: http://www.e90post.com/forums/showth...=sticky+brakes

On page #4 post #77 a member found a potential solution to it, i will be bringing in my car soon hopefully to have it looked at.

I still contend that the symtoms that we are describing are in no way, shape or form a "feature" or "normal" as some have suggested.

That thread describes exactly what I have!

[cas]

Originally Posted by g2artist

This is not brake assist.....my problem happens when the car is cold and goes away after about 10 minutes of driving. WHEN I'M AT A STOP ON FLAT GROUND, I slowly let my foot off the brake. The car will suddenly jerk forward and start rolling practically giving me whiplash. Feels as if someone is giving me a fender bender from behind everytime I let off the brakes. I cant even get the car to slowly ease forward (as is needed in parrallel parking) by letting off the brakes as slowly as I can. Everytime I let go of the brake even slowly the car JUMPS forward. When the car is warm it wont do it. I can easily let my foot off the brakes slowly and the car will start rolling forward while RIDING the brakes.

I have an E93 built 10/07 and it does the same exact thing. The below though has a cut off of 09/07 so Im wondering

[F104]

Originally Posted by SteveC

German cars have an anti-stall feature that in manual cars allows you to take your foot off the clutch with no gas and the car will move slowly but smoothly forward...no pecking duck starts. At the same time cars have an enrichment cycle that increases the amount of fuel when the car is cold. If this anti-stall feature was set up a little too aggressively, you would get exactly what you're talking about. Alternatively, if the engagement of your AT was a little to abrupt when its oil is cold, you'd get the same thing. Either way, this sounds both uncomfortable and abnormal and is something your dealer should be able to rectify. However prepare to be without your car for a few days as prolems related to cold running are more difficult to diagnose, since the car has to be cold to find it (obviously), which limits the time available for diagnosis.
One way to tell whether this is fuel supply or gearbox related would be to warm the car up without driving it then see if the problem is still there. If it persists for the usual time after the engine is warm, its transmission. If warming the engine means the problem is gone as soon as you drive, its related to the fuel injection set up.

This is a little OTT. Anti-stall feature? If you can't get a 3 ltr to drive off without using the throttle you should buy an AT or go back to driving school. What are those poor folks in 1.0 ltr cars doing? Jump out and push it? Yes all cars will run rich when they are cold.

[SteveC]

Originally Posted by F104

This is a little OTT. Anti-stall feature? If you can't get a 3 ltr to drive off without using the throttle you should buy an AT or go back to driving school. What are those poor folks in 1.0 ltr cars doing? Jump out and push it? Yes all cars will run rich when they are cold.

Here you go

http://www.topbuzz.co.uk/info/iscv/iscv.htm

Live and learn!

[SteveC]

More sophisticated units ala BMW are controlled by the ECU in conjunction with several sensors. The following provides useful background

http://www.autoshop101.com/forms/h26.pdf

You can imagine that a malfunction or inappropriate operation of this unit could very well cause the symptoms described above

[jhbodle]

RyanDe680 has it right. It's the NIC calibration and its supposed to be solved by a software update. However, the bulletin that he posted has now been superceeded:

http://www.bmwtis.com/tsb/bulletins/...p/B240308g.htm

"The NIC (Neutral Idle Control) feature disengages the torque converter from the transmission when the vehicle is stationary in the Drive position; the service brakes are applied; and the engine is still in the warm-up phase. The NIC function eliminates engine load when vehicle is stopped, reducing fuel consumption."

The first bulletin upgraded the Progman to a newer version, which improved the problem slightly but was still there. Apparently the latest software version with the "Converter lockup clutch" retrofit fully fixes the issue, but my dealer won't do it for me because they "can't reproduce the problem", which drives me mad because yesterday I was pulled over by the police saying that my car was rolling back and then pulled away sharply - this is what the transmission does if I am on a hill when the engine is cold, the car rolls back, I overcompensate by adding more throttle and then the gear kicks in and it jolts away.

[ramorendez]

I had the same issue for the first couple thousand miles (11/07 build). I wasn't able to replicate it whenever I brought my car in. Hasn't happened since about 3k miles - I'm going on 12k now.