Did it again on the way home. When the anti skid icon comes on, the speedo jumps around and the car ends up stuck in 2nd gear for a bit..

 

You probably have a bad tone ring on one of your axles. Here's a way to diagnose this, jack the car up, remove the front wheels, peek behind the rotor and unbolt the wheel speed sensors (ABS sensor), pull them out, use a flashlight and look down into the hole that they fit into, you will be able to see the tone ring, which is basically just a gear that has notches that allow the wheel speed sensor to determine the speed of the wheel. While looking down this hole at the tone ring spin the rotor, so the axle spins. Look for any flakes of metal or damage to one of the teeth while spinning the axle. Do this on both axles

 

Thanks for the suggestion. I have also noticed this horrible noise in the front driver wheel when I turn hard to the left and come to a stop. It's like a loud high pitch squeal that sounds as if something is dragging as well. It will do this even when the car isn't running and the car rolls slightly when I let off the break after parking (I don't use the e brake). Sometimes when coming to a stop downhill, I also feel like there is subtle resistance and there is an odd tone. Wonder if those sounds/issues could be related to what you described. I only just thought about those issues when you mentioned that.

 

Could definitely be a bad axle, I'd get it up on stands and check the tone rings at least. I had a weird grinding noise when turning left at speed a while back, turned out I was low on power steering fluid.

 

I pulled the wheels and ABS sensors and had a look and all the teeth look good so that doesn't seem to be the issue

 

BCM acting up?

 

Is that the brake control module? If so, that is what I am assuming is wrong and seems to be well over $1k.

 

take it to dealer for proper diagnostics.

 

They were the ones that told me that there were no codes the first time and the second time that it was the front ABS sensor. I replaced it and the issue persists... Why would I take it back?

All the tone rings I've ever replaced have been cracked between the gear teeth. It will be a hairline crack but it's enough to cause an irregular reading and set the car into a fit. Look very carefully with a good light. Esp at the side that threw the ABS sensor code.

I will double check that, thanks for the further insight.

 

All the tone rings I've ever replaced have been cracked between the gear teeth. It will be a hairline crack but it's enough to cause an irregular reading and set the car into a fit. Look very carefully with a good light. Esp at the side that threw the ABS sensor code.

 

When the icon with the car and skid marks comes on and the car goes into limp mode for a few seconds, is that generally related to the ABS issue or is that a sign of something else? I always read about people having the ABS icon on and anti-skid message but rarely read about the other icon coming on the dash where the car just won't go. It did this 4 times yesterday when leaving work getting onto the highway.

 

When I had my tone ring issue I had these symptoms: under light braking the ABS would kick in and not slow me down, then instantly I would get 4-5 messages on the dash, anti-skid service required, abs temporarily disabled, dstc spin control temporarily disabled, brake service required, (something along those lines, may not be the exact messages). I also got the brake warning light and CEL. Car would go in to limp mode, I couldn't boost above 6psi and changing gear was extremely difficult to do smoothly. Resetting the ECU was the only way to make these messages to away, but the next time I gave the car maybe 10% braking power it would happen again.

 

I plan on looking at those again this eve. Thanks for the help on this.

Also note, it only seems to go into limp mode with that icon when the car is cold i.e. leaving my parking garage at work or leaving my house in the morn.

 

Still no luck tracking down the source of my issues. I noticed something else which may help narrow it down. If I start the car in the morning, the ABS light comes on when I haven't moved the car or hit the brakes. Would that be an additional sign of the ABS computer/control module? Also, I had described this horrid screaching noise in the front driver wheel when going very slow and only when turning to full lock. If I park at full lock and the car rolls a hair when not running, it makes the noise as well. Someone had mentioned it could be a bad axle. Could that cause the ABS issues as well?

I am getting sick of this issue and as I stated before, I took it to a dealer and they couldn't figure it out so I really don't want to do the insanity thing again by taking it back only to be charged diagnostics and to be without a car for nothing... I really am amazed at how little response I have gotten (except for the 3 who have tried to help for which I greatly appreciate)

In summary, I almost always get the ABS light on when I drive. It seems to come and go with no rhyme or reason. Sometime I also get the traction icon with the skid marks and when that happens the car goes into limp mode and will not move. I just have to keep trying and eventually it will go but when it does, it won't shift for a while. When this stuff happens, the tach seems to jump sometimes. Lastly, I sometimes get the "Brake Failure" notice but I never have a brake failure.

Is it possible to disengage the ABS and traction control via software? I need to get this fixed as I worry it will go into limp mode when my wife is driving with our newborn baby while trying to get on the highway etc.

 

I know there are a few automotive techs that frequent the forum. Maybe you can PM someone like cattlecar to see if he can look at your thread and at least give you some guidance on what to do next.

 

Did the insanity thing and took the car back in. Hopefully they get some new codes and a better idea.

 

Wha wha whaaaaa. Lots of failure to communicate codes. So it seems I have to replace the control module and then hope there is nothing else.

Does anyone have a source for a new module that is less cheaper than the dealer asking price of $1200+?

 

get a remanned unit from xemodex.com

 

Sure its not the DEM or a lack or power to the BCM causing the communication codes? As long as power/ground and network wires are checked @ the BCM, it is likely your problem.

 

I am not sure. How would I know if it's the DEM. That is what scares me. They even said they can't tell anything until I replace the BCM since they cannot communicate. So I could be out $1200-1600 for nothing... So you are saying so long as the ground and power to the BCM are good, it is likely that it is the BCM that's bad correct?

 

My limp mode issue has been getting progressively worse. And since my BMW is so close to being finished, I have zero desire to spend $1600 fixing this car. So I just pulled the ABS fuse and so far, no more limp mode issues. One thing that surprised me was that the suspension seems to be stuck on firm. Does the ABS and 4c system work together? I always used to notice my front suspension seemed a little loose almost like a blown front shock. But I replaced them a while back. Just thinking that the issue could have been related to my failing ABS computer the whole time.

 

so can you post up your codes, im assuming that you have 1A codes in the cem for no communication with BCM and possible E001/E000 codes in all other modules for faulty communication on the CAN bus? check the 2 fuses to your bcm and if they are good and all other modules are communicating on the high speed network its most likely your bcm.

 

I'm having practically the same issue but without messages and codes!
ABS kicks in when you do a slight hard braking and I have no power in my leg to force in my brake pedal and wheels block like I have no ABS at all!
I believe it is BCM or something to it related!
Have new rotors, pads, brake fluid and all my calipers are rebuilded with new pistons and seals! I just get used to that problem!

 

http://xemodex.com/technologyimproved/brake-control-module-for-volvo

 

Does anyone have experience with those? I have read nothing but bad things about remans but at this point all I want to do is fix it so I can trade it in. I also don't see a version for the VR.