BMW E46 Fanatics Forum banner

1 - 20 of 30 Posts

·
Registered
Joined
·
4,698 Posts
Discussion Starter #1
Looking for more ideas on what could cause both these lights to come back on. Little bit of history and recent maintenance.

My DSC and Brake light both came on so I took it into the dealership. This is about a week after I had my front control arms and bushings replaced, and the car aligned.

So the dealer diagnosed the problem to be my DSC Control Box, so I had that replaced along with my Brake Fluid flushed and a coolant flush.

About a week later both lights came back on, had the Steering Angle Censor replaced.

Now a week or so later both lights came back on :banghead: Anyone have any ideas?

Cliff Notes:
New Control Arms + Bushings
Alignment
DSC/Brake light on
DSC Control Box replaced and Brake and Coolant Flush
DSC/Brake light on
Steering Angle Censor replaced
DSC/Brake light back on...

Thanks
 

·
Registered
Joined
·
121 Posts
Having the same problem. Waiting for someone to figure out how to test the wheel sensors. I had a lot of metal shavings on my front two, but cleaning it didn't help. You did check your brake fluid level, right?
 

·
Registered
Joined
·
4,698 Posts
Discussion Starter #5
Having the same problem. Waiting for someone to figure out how to test the wheel sensors. I had a lot of metal shavings on my front two, but cleaning it didn't help. You did check your brake fluid level, right?
Brake fluid was just flushed, but I will check the level tomorrow.

Are there any drive-ability issues? Of is it just the dash lights?
No drive-ability issues that I have experienced just the dash lights.

I guess I will also have to have the wheel speed sensors checked.
 

·
Registered
Joined
·
1,176 Posts
Are you also getting the traction control light as well? I get all three intermittently and although I've never had the codes read I'm 99% convinced mine is a rear wheel speed sensor. The reason I'm so sure is I seem to be able to get the lights to go out by turning the car off, yanking up hard a couple of times on the e-brake then restarting...brake light goes off immediately then the DSC and traction lights go out as soon as I go above about 20mph.

Some other things I've observed (at least in my case)...it seems to be more prevalent when there's moisture present, like after washing the car if you don't drive it for awhile right away, or if it's really humid over a period of days it seems to do it in the morning on first start up. I'm theorizing that over time/mileage, the wheel sensors get worn and finicky and if moisture penetrates them they give off a false warning.

I tried pulling one out to clean it, but it's so darn tight in the socket I was afraid I'd ruin it (didn't have a replacement on hand) so I just let it be. I had virtually no false alarms over the winter (colder & drier air) but as the summer has gotten hotter and muggier, they seem to have become more frequent. I've contemplated replacing them but at $100/each I wish I could be sure which one it was. I'm planning on doing the brakes/rotors this summer so when everything is off and I've got better access I hope to see if I can clean things up a bit.

Not sure if you have the same problem, but it sounds like it might be. Dealers always seem to point to the main control unit which costs around $2K to replace or $700 to rebuild. Gee, I wonder why? Good luck with the diagnosis. Let us know what you find.

//GG
 

·
Registered
Joined
·
4,698 Posts
Discussion Starter #7
Thanks for the response the only reason I don't think its the wheel sensor is that would cause my abs light to come on as well and that has not come on at all. Unless the wheel speed sensor would only causen the brake And dsc lights to be on.

Also checked my brake fluid this morning and its full.

Are you also getting the traction control light as well? I get all three intermittently and although I've never had the codes read I'm 99% convinced mine is a rear wheel speed sensor. The reason I'm so sure is I seem to be able to get the lights to go out by turning the car off, yanking up hard a couple of times on the e-brake then restarting...brake light goes off immediately then the DSC and traction lights go out as soon as I go above about 20mph.

Some other things I've observed (at least in my case)...it seems to be more prevalent when there's moisture present, like after washing the car if you don't drive it for awhile right away, or if it's really humid over a period of days it seems to do it in the morning on first start up. I'm theorizing that over time/mileage, the wheel sensors get worn and finicky and if moisture penetrates them they give off a false warning.

I tried pulling one out to clean it, but it's so darn tight in the socket I was afraid I'd ruin it (didn't have a replacement on hand) so I just let it be. I had virtually no false alarms over the winter (colder & drier air) but as the summer has gotten hotter and muggier, they seem to have become more frequent. I've contemplated replacing them but at $100/each I wish I could be sure which one it was. I'm planning on doing the brakes/rotors this summer so when everything is off and I've got better access I hope to see if I can clean things up a bit.

Not sure if you have the same problem, but it sounds like it might be. Dealers always seem to point to the main control unit which costs around $2K to replace or $700 to rebuild. Gee, I wonder why? Good luck with the diagnosis. Let us know what you find.

//GG
 

·
Registered
Joined
·
258 Posts
My 328i did this about 4 different times while it was under warranty. Every time the dealer diagnosted it as a wheel speed sensor and after cleaning it or replacing it the problem went away, for a while anyway a good 12-18 months or something like that.

After the warranty expired it went about 3 years without the problem until recently. I took it to the dealer where it was diagnosed with about 5K dollars worth of repairs (LOL) which included a new DCS module because "the rear right sensor shorted causing damage to the DSC " Bull!!!!. The wanted to screw me with some many things is unbelievable. Of course I didn’t believe them, the only reason I took it in was that they are the only ones who can tell you exactly which sensor it is. I ordered the sensor online, replaced it and all lights went away.

So I recommend you do the same. Take it to another dealer. Ask them to diagnose which sensor is giving the error and replace that one. Done.

Pancho328i
 

·
Registered
Joined
·
258 Posts
Having the same problem. Waiting for someone to figure out how to test the wheel sensors. I had a lot of metal shavings on my front two, but cleaning it didn't help. You did check your brake fluid level, right?
Pay the dealer to diagnose and replace the sensor. They will likely charge you an hour labor just for diagnostics. Unless you let them replace it which then diagnostics is free, and the hour labor is for the sensor (I replaced mine in 5 minutes tops). The sensor itself is about 85 dollars online. about 120 at the stealer.

Pancho328i
 

·
Registered
Joined
·
258 Posts
Thanks for the response the only reason I don't think its the wheel sensor is that would cause my abs light to come on as well and that has not come on at all. Unless the wheel speed sensor would only causen the brake And dsc lights to be on.

Also checked my brake fluid this morning and its full.
They do. Wheel speed sensors cause the ABS, brake and DCS control lights to come up in random combinations that sometimes vary from one day to the next. Don't ask me why. I'm just talking from 8 sweet years of ownership here.

Pancho328i
 

·
Registered
Joined
·
141 Posts
1. Which DSC sensor did you change? Where was it located?
2. Did you use a DIY on how to change a DSC sensor? If so, can you direct me to it?

Thanks!
 

·
Registered
Joined
·
1,176 Posts
1. Which DSC sensor did you change? Where was it located?
2. Did you use a DIY on how to change a DSC sensor? If so, can you direct me to it?

Thanks!
The speed sensor is #21 in the attached (from RealOEM). To replace it you need to remove the screw that holds it in then pull it out. I tried to pull one of mine to clean it and found it so tight in the trailing arm that I figured I'd ruin it trying to get out (it's plastic). Since I didn't have a replacement handy that would have been a problem so, truth be told I never completely replaced it. Problem still occurs intermittently and one of these days I'll bite the bullet and have the dealer diagnose and replace it. For now I'm just too damn cheap and it's more of an annoyance than a real problem.
 

Attachments

·
Registered
Joined
·
258 Posts
1. Which DSC sensor did you change? Where was it located?
2. Did you use a DIY on how to change a DSC sensor? If so, can you direct me to it?

Thanks!
Mine was the right rear sensor. Replacing it is, like others said, very easy. Just remove the screw that holds it to the wheel hub, pull sensor out, follow the wiring into the connection box, unplug it (press on the tab that holds the conector inplace), plug new one in. Done.

When you remove the sensor you can see the dented wheel. I cleaned it with brake cleaner while rotating the hub. I used a screw driver to clean some dirt in some of the teeth.

Rear of car has to be on stands of course, and the wheel off.

Pancho328i
 

·
Registered
Joined
·
258 Posts
The speed sensor is #21 in the attached (from RealOEM). To replace it you need to remove the screw that holds it in then pull it out. I tried to pull one of mine to clean it and found it so tight in the trailing arm that I figured I'd ruin it trying to get out (it's plastic). Since I didn't have a replacement handy that would have been a problem so, truth be told I never completely replaced it. Problem still occurs intermittently and one of these days I'll bite the bullet and have the dealer diagnose and replace it. For now I'm just too damn cheap and it's more of an annoyance than a real problem.
They shouldn't be that tight prcisely because they are plastic. They don't rust. Once you have the screw out try rotating it a bit, just give it a little play rotating it left and right. It will come right off.

pancho328i
 

·
Registered
Joined
·
44 Posts
Guys, on my 2001 330i had the same problem. I replaced the lower intake boot (the one with the accordion coming out of the side) and the "check engine soon" light along with both, brake and traction control lights are gone and have been for nearly a year now.
 

·
Registered
Joined
·
161 Posts
There is a pressure sensor on the master brake cylinder, you may have your dealer to check from GT1 to see if this is the sensor at fault.

It seems to be a rather common faulty item recently.
 

·
I SHOP @ TURNER MOTORSPORT
Joined
·
765 Posts
I have had these lights come on in my Mini and it turned out to be a wheel speed sensor. It would come on intermittent and then i could get it to come on with hard acceleration and also hard left turns...lol. The first time it was a steering angle sensor but you said you replaced that already. I was also told that air in the lines would cause the lights. Since all those systems are tied in together....:banghead:
 

·
Registered
Joined
·
2,577 Posts
Adam, do you by any chance have a blower kit on your car?
 
1 - 20 of 30 Posts
Top