[cmg5461]

Hey everyone,
Today we had the first big snowstorm of the season for the east coast. It down-poured on my morning commute which made me notice an issue with the xdrive traction control while braking.

I've noticed this one or two times before during heavy rainstorms - applying the brake in both right lane and left lane (it's not hydroplaning) causes the car to pull hard left. The first time it did it, it freaked me out. It feels like taking a sharp exit on the highway when you almost miss it.

This occurs under all braking pressures - hard or light

Today it was continuous rain on the way up to work and snow on the way back. I notice this behavior in back to back braking - it never goes away. In order to catch the car, I have to anticipate a 15 degree steering wheel rotation to the right before I brake.

The car brakes perfectly straight in dry conditions.

I'm stumped.

[ucdbiendog]

and it doesnt do this when dry? check the tires? also, there is a rain sensor on the brakes, perhaps the brakes on the right side aren't getting properly dried?

[pits200]

I think this is an xdrive issue. I have the same problem. It's during highway driving when you don't need to use the brakes for an extended period of time let's say 15 minutes or more. And I've learned now to never brake hard due to that pull that scares the he'll out of me.

As for tires, I have Michelin as3 and before that the zupersports and both tires had the issue along with my current set of winter tires. It's not alignement I have those done every six months.

Only thing I can think of is the brake dryer feature where the car lightly applies the brakes automatically to dry the rotors when highway cruising. I think it's possible they apply unevenly on all four corners and some of the rotors get dryer than the others hence the propensity to pull to one side. It's soooo dangerous and the dealership said they never heard of this issue before

[LeeCatD8209]

I had this same issue last Summer on my way to Georgia in a torrential downpour. Haven't really experienced it again.

[zipstic]

I can't think of why it would have anything to do with the AWD/XDrive system. (I assume you're not pushing on the brake and accelerator at the same time.) When you take you foot off of the accelerator the power is being taken away from the wheels and the system is not shifting the power from one wheel to another. My first guess would be the rain sensors. My second guess would be the traction control. Have you played around with using DTC and DSC settings?

[cmg5461]

I tried it yesterday with DTC off and completely off - still pulled. When I turned my wipers off it seemed to get better, but when I put them back on I couldn't recreate the problem

[pits200]

Originally Posted by cmg5461

I tried it yesterday with DTC off and completely off - still pulled. When I turned my wipers off it seemed to get better, but when I put them back on I couldn't recreate the problem

Did you use the auto rain sensor wipers? (Press in on the side button)

Supposedly, the brake dryers only activate when using the rain sensor function and would make sense why you were experiencing things like you were.

[cmg5461]

Originally Posted by pits200

Did you use the auto rain sensor wipers? (Press in on the side button)

Supposedly, the brake dryers only activate when using the rain sensor function and would make sense why you were experiencing things like you were.

I tried both, wipers on auto and on. Same behavior. I'd imagine the rotor wiping to work with the wipers on anyway also.

[ucdbiendog]

so i experienced this this first time this weekend. to fix it i would periodically tap the brakes to keep them heated. very frightening indeed if you arent expecting it. did OP find a resolution?

[NOITALL]

Doesn't the car apply the brakes automatically to dry the pads when the auto wiper is on (and being used)? This should solve your issue?

I've never experienced anything similar either way.

Cheers

[ucdbiendog]

i never had either until this weekend (120k miles now). my auto wipers are always on. OP tried with auto and not auto and it didnt fix the issue. once i get the car in a garage ill be able to get the wheels off and take a look around there.

[zmon1300]

I have the same issues. Scares the hell outta me. I just lightly pump he brakes if I need to slow down and that'll usually do it. Anyone have a better solution?

[tc535i]

In older 3 series, this was a trailing arm bushing issue. In higher mileage cars, I'd start there.

[pits200]

This is 100% a rain sensor brake dryer issue.

[cmg5461]

I haven't found a resolution, just been dealing with it

[Nick54]

reviving this thread... I recently got a 335i xdrive and I'm experiencing the same problem. has anyone found a fix for this?