[Kyle Matthews]

Did the same thing - works! I had errors for about 10 minutes after putting it back together (but had forgotten to roll the wheel all the way left, right, and back to center - dunno if that affected it). Since then it's been a few days, and I've seen no repeats of the errors. Previously even if it turned off for a few minutes, it'd be back as soon as I turned.

I took a few photos while doing this, to clear up some points and since a couple were blurry in the original post. Feel free to use as you'd like!

[PTek Will]

So I tried all the steps other than soldering, basically cleaning out the optical disc but it didn't fix anything. I lived with the dashboard lights for at least 6 months. Then one day, a buddy and I went on a very spirited drive. Afterwards, the lights went away, my cruise control, traction control, abs and hill assist all started working again! yay! lol

[tokyowolverine]

First off, thanks for this DIY. Pics and description were awesome.

I am pretty good friends with the service guy at my dealership and he offered to replace just the optical disc for $150 using the SZL Repair Kit:
http://www.ebay.co.uk/itm/BMW-SZL-Re...-/300880850396
He said it had a 70-80% chance of working and thankfully it did.

To tell you truth, the DIY was so well written, I was tempted to do it myself, but my friend said that you need to be careful with static electricity and dust on the disc...I figured $150 was a fair price anyway so had him do it.

When I got the disc back, I understood why the IR sensor was having a hard time calibrating...it was coated with the white, crystal-like substance you mentioned...like a bunch of snowflakes. Pic 1 is a close up of this.

Thanks again for your DIY.

[LUCPO]

Hey man, thank you for this post, I just finished cleaning my optical disc after I followed your DIY and it seems that my car is now working just fine. I hope that it will last. You saved me 500E.

[aakrusen]

^^ It will last. I did this DIY on my car 2.5 years ago and I haven't had an issue since I cleaned the disc.

[djordje]

Hi there. Didnt help me. First i clened just the top side of the disk, yesterday i remove the IR led cover, clened it, remove the disk and cleaned it from both sides. It was fine for 30 minutes drive, and than again bang christmas tree. Every time i start the car it starts without the icons, and after 10 min drive they comes up. Maybe i should try to clean the sensor and ir led also. Im cleaning with plastic cleaning wipes. I think ill have to buy used sensor and recode the car after. Thanks.

[djordje]

Hi there. At the and i and up by changing the whole unit. I have found used switch, same spec, but made for 4 cylinder cars, part number 61319123041. What i had before in my car was the 61319123049, same spec unit but for 6 cylinder cars. They coded the old new switch to the car, and now everything is fine, all working good. Visually what i found is that now the symbol in red circle is missing, beside this all is ok.

im giving this info to anyone that and up changing the unit, you can use the same unit from 4 cylinder cars also, no matter it is another number. Cheers.

[AndyR83]

Great writeup here on a common problem. Thanks for posting!

[new0rder]

Originally Posted by RogerRamjet

Many thanks to the OP!!

And finally, one major comment: Shame on BMW for not addressing this serious safety issue free of charge. This optical disk issue should've been a safety recall. I love my car but I've lost a lot of respect for BMW on this one.

I am having the same issue, the safety of this concerns me, kinda dangerous when the whole car will shut down at low speed/ come to a stop. I will do the clean up fix but this issue is not sitting well with me, come on BMW help us out. BTW this issue just started with me 3 month ago. 4x4 lights / xmas light came up after hitting a bump. then car shut off after I come to stop. not happening all the time but when it does, its a pain.

[Max555]

Hi All

Firstly a Big Thanks for to the OP.

Just thought I'd share my recent experience. For a while now I was experiencing intermitent issues with my iDrive, where the screen would change by itself to various other screens. Thinking it could be a sign that the battery was on it's way out I had it checked and despite being told that it was fine decided to replace it anyway as it was getting on 7 years old. Then I got warnings all of a sudden that my DCS, DBS and Tire Monitor had failed, also my indicators no longer self cancelled. Diagnosis was Faulty DCS Steering Column Sensor quoted second hand fitted $830 New $1500 (not from Dealer).

Problem fixed for less than 1 hours work and the cost of 1 alcohol swab from the chemist. The optical wheel cover was covered in a crystal like substance that wiped away with the alcohol swab and problems all gone. I din't go any further than wiping over the disk once. No warnings, and indicators self cancelling again.
Needless to say I am one happy guy at the moment. Also no iDrive issues as yet either.

[AoS810]

Thanks for the pic Max555, thats exactly what mine looked like as well.

Add me to the list of a successful fix! Just a note that when I started up the car, the error lights were still there, even after I did full lock to the left and right, but when I pulled out of my driveway and drove about 20 feet the lights went away and have stayed off *knock on wood*

I used 91% isopropyl alcohol w/ qtips and makeup removal pads (lint free). I did not remove the optical disk from the housing, just removed the plastic led cover and cleaned all 3 thoroughly (disk front part only, plastic cover, led). I did not do any heating/soldering.

The hardest part was removing the steering wheel cowling as instructed in step 8 of the diy. The trick which eventually worked for me was using a flat head to wedge (at the part where the upper and lower cowling come apart like in pic #8) right in between the cowling and the steering module thing which holds the optical disk and just slowly/carefully pry and it popped right out.

Reinstalling everything was really straightforward but again, that steering wheel cowling.. I had to install the bottom piece before I put on the top piece, could not get it to be flush otherwise. I also used quite a bit of force to pop them in place.. just make sure that all the locking points line up and just push your heart out!

Lastly, thank you yikes98!

[new0rder]

over the weekend I was able to do all the way to the optical disc part, my disc was clean no dust at all, so I close everything up and put it back, today I drove 20 miles temperature was 75 degrees outside, everything was ok until the end when I hit a bump so the car went re-calibrating you notice how the engine react, then the x-mas lights came on, then the car lost power while the car is still running, so I have quickly pull over the shoulder and after a min the battery/power is back. why would the power die, kinda like a reset. any suggestion? thank you

[Max555]

Originally Posted by new0rder

over the weekend I was able to do all the way to the optical disc part, my disc was clean no dust at all, so I close everything up and put it back, today I drove 20 miles temperature was 75 degrees outside, everything was ok until the end when I hit a bump so the car went re-calibrating you notice how the engine react, then the x-mas lights came on, then the car lost power while the car is still running, so I have quickly pull over the shoulder and after a min the battery/power is back. why would the power die, kinda like a reset. any suggestion? thank you

Could be a lose battery connection or something along those lines.

[rrdesign]

Thanks to yikes98 for a great tutorial. My E87 130i has been running for a week now with no christmas tree lights. Prior to that I could not go for a day without resetting the steering sensor.

My optical disk did not have any snowflake deposits, but had what looked like a speckled wax coating which had dissolved into several raindrop like blooms in places. When I cleaned it with the alcohol it left a dirty deposit on the q-tip. I also carefully cleaned the IR emitter. All good now (fingers crossed)

Also I found this video which clearly shows how to remove the airbag:

[shwinturbo]

FYI - cleaning the disk and the led lense worked for me!

this is what mine looked like, didnt even look that bad...cleaned it with regular alcohol pad wipes - 80%

[jaco_ma]

Magmifica Guide !!

Thanks for sharing ...

[glachhman]

I have an szl if anyone gives up and just wants to buy one.

[nerovega]

Followed this DIY up to the clean disk part. After reading that so many were able to remedy the situation by just cleaning the disk I did the same and it worked for me. No more lights on the dash. I'm pretty convinced now that this problem is mostly caused by the crystal-like buildup on the scan disc. I'm not saying this is the solution for everyone with the DSC and Yellow brake light warnings but it seems 95% of the time it is the scan disc.

I cleaned it off with 91% alcohol.
I did not clean the infrared light, just the front side of the disc.

Did this about 2 months ago and still no reoccurrences. Even if it comes back because of more buildup, I don't see it happening anytime soon and when it does its way cheaper to just clean again then pay $500+ for the part.

[Welcome to NBA Jam]

Thanks for this post, OP! Very fascinating, but disappointing that it suffers this design flaw. My DSC/BRAKE lights came on after service yesterday, but my indicators still work. I'm still under CPO, so I'd rather have them fix it. I doubt that this is the problem, but it's great information for the future.

This post made me very interested in figuring out how the steering angle sensor works, and I've been able to figure it out. Here's what I understand so far, please correct me if I am wrong:

It's very clever. The disc is called an absolute optical encoder. The reason why there are so many tracks on it is because, for every single point on the outer slits, there is exactly one unique combination of dark/light slits going from the outside down to the center. Or, in other words, a specific combination of 1/0 (for a total of 2^t number of tracks: the exact number of slits on the outer track). This is why the sensor looks like a line - to detect that combination and translate it into an angle. For each combination of light/dark, a position on the disc can be determined down to a certain degree resolution. The more slits on the outer edge, the higher the resolution. Thus, the steering angle sensor is able to determine not only angular speed, but its exact position as well.

As opposed to the E46, we can recalibrate the steering angle sensor by turning lock to lock, then centering. The E46 sensor uses the hall effect, and is incremental only. For it to determine position, it requires an initial reference value that is stored externally from the encoder.

Good video explaining it all here:

When the disc is covered in that crystalline stuff, it obscures the encoded values trying to be read by the sensor. When the sensor can't read them, it doesn't know the position, and spits out an error. Keeping the encoded disc perfectly clean and free of debris or dust is key for the steering angle sensor to function properly, and the protective coating already on it clearly deteriorates. It wouldn't even be a bad idea to lightly coat the front of the disc with a dust repellent.

[Trashhauler]

Thanks for the tute for the SAS fix.

My 330i started exhibiting the same faults you describe. I used your fix sans the soldering and the faults all cleared. Best fix on the web for the E90.

Cheers

TH

PS - the optical disk, LED lens and the receptor lens were covered in an oily substance. I used eye glass clearner designed for plastic lenses cleaning both sides of the diskl and the LED lens.

A few others had remarked that the LED lens had become somewhat opaque - the same with mine however after using the lens cleaner it looked like new.

[omniphil]

I was convinced I would have a dirty wheel too as I have the steering angle fault lights and a 6 year old car.

After taking it all apart using this awesome tutorial I found what looked to be a very new looking wheel and sensor. Damn. So I guess its the circuit board. I also tried having the sensor re-zeroed. That didn't work either.

I'm pretty handy with soldering, what are the main areas people are re- soldering?

[FrankyGTR]

Yes fixed my 08 335i after months with no cruise control.just cleaning with qtip and 70%alcohol