A few weeks ago, my car exhibited classic steering angle sensor (SZL) failure simptoms - at the first instance of turning the steering wheel after starting the car, I'd get errors indicating falts with the DSC and the FTM. I'd read about this this fix My $0.02 Steering Angle Sensor Fix - BMW 3-Series (E90 E92) Forum - E90Post.com a while back, and decided to try some aspects of it before giving my car up to a mechanic for a day or so.
Specifically, I pulled the steering angle sensor, opened it up and cleaned the top side of the optical disk with glasses cleaning solution and a lint free, super fine weave, microfiber glasses cleaning cloth. One of the posts recommended isoproyl alcohol, which I did not use, because alcohol can craze some types of plastic and the optical disk is plastic. The glasses cleaning solution said it was safe for plastic lenses.
There was, in fact, a nasty brown film on the disk. I thought about cleaning the bottom side of the disk (the side with the pattern deposited on it), but I was worried about damaging the pattern, so I didn't. I also unscrewed the clear block that transmits light from the LED (it needs a tiny, maybe T-8 Torx driver). It was a bit yellowed (not crystal clear looking), and the cleaning didn't seem to change that.
I did not try to re-flow any of the solder connections.
I put all back together and drove it around on and off Sunday and to work this morning. I've not got the error again. I'm not saying that it was the cleaning that fixed it. It could have been that I'd had a lose connector. However, whatever I did seems to have fixed it.
Some things to know:
- The DIY linked above is for an e90. Our e60s are a bit different. The steering angle sensor looks the same and is in the same place, but getting to it is a little different. If you're mechanically inclined, it is not hard.
- You don't have to re-code the steering angle sensor to the car if you do this, because you're changing anything.
- Some early e60s had the clear block over the LED changed. Therefore, you can order a new one. If my issues come back, I might do that.
Current: 2008 e60 DINAN ///M5 Interlagos Blue SMG
DINAN 3.91 Differential, Stage 2 Suspension, Free-flow exhaust, Stage III Software, Front strut braces,
High Flow Air mass meters and intakes, 13% Underdrive pulley, RPI Scoops.
Now instead of being a tease, post step by step instructions (with pics) on how to remove the SZL for an e60 since you have our attention.
It is too late for that, but the differences were really nominal. For example, to release the airbag, you put a screw driver into the back of the steering wheel and compress a spring. The e90 write up showed two holes to access the spring. Because we have SMG paddles, there's only one hole to access spring. In another example, the clips that hold the top and bottom halves of the steering column cover are of a different shape than those in the e90 write up, but like the e90 clips, they come apart by prying the top and bottom halves apart. In yet another example, the Torx screws that hold the unit in place are in slightly different locations in the e90 than they are in the e60.
In short, once you've seen the e90 write up, performing it on the e60 is easy.
It is too late for that, but the differences were really nominal.
I did the same repair, but do not have pictures for a DIY.
The only special tools needed are some small torx screwdrivers (T-6, T-9, T-10, T-15). This is the first time I've used a T-9
I cleaned both sides of the optical disc using Meguiars Plastic Care #10 and #17.
The upper part of the disc was much worse than lower areas, so heat might be a cause. The sun bakes the top of the steering column where the optical disc is housed.
Removing the PCB and reflowing the solder was not needed.
I'm glad I found this post, it really works! First I was using already mentioned above 'My $0.02 Steering Angle Sensor Fix'. When I took the circuit board out, it seemed ok to me and I did not want to solder the connectors. Then I found this thread, cleaned the disk and everything worked!
Saved me 950$ (quote from a smaller repair place), dealership wanted about 1200$.
I took the pictures when putting it all back together. Will post them with my notes shortly. Clyde says he used T-9 - it was too big, I used T-8. As for cleaning, I tried Windex first, it did not help much. But Oil-eater did the job.
1) Park the car. Make sure the wheels are strait. Disconnect the battery in the trunk.
2) Remove horn/airbag. There's a hole under the steering wheel. Insert a screwdriver or allen key (size 15-20). Find correct position, slightly moving the screwdriver back and forth. Then push the screwdriver upward to release the inside spring. First time it took me several minutes - I did not want to break anything.
3) Disconnect the horn/airbag. Gently push the tab with you finger or screwdriver, then pull to disconnect.
4) Remove the steering wheel bolt. Use 15mm 6 point socket (12 point socket is not very good for this). I don't know how to lock the steering wheel, so I needed second person to hold it while I was undoing the bolt.
5) Remove the steering wheel. Disconnect the wires by pulling the connector out
6) Remove the cover from the cowling. I did not use any metal tools here. Apply finger pressure and pull the cover towards yourself.
7) Using T10 Torx key remove turning signal, cruise control and windshield wipers controls.
8) Remove the bottom cover of the cowling. There's plastic screw on the bottom, be careful when removing it. Then apply finger pressure to the top cover and pull the bottom cover down. Do left and right sides separately, one at a time. Leave the bottom cover hanging down. Don't remove the top cover.
9) Using T15 Torx remove 6 screws. Then carefully pry big tabs on each side to release the big round module. I could not remove it completely until later, as the wires on the back hold it.
10) Remove SRS module ($545+tax at the dealership) from the brackets. First pull the bottom part out, but not completely. The wires behind it at the bottom are still holding it. Then wiggle the module out from the brackets. Don't rush - find a way that works.
11) Disconnect the wires from the back.
12) Now I was able to separate completely big round module from the SRS module.
Using T8 Torx remove 4 screws. Note the arrow alignment for later - when you're putting it back together.
13) At this point you could clean the disk. I took it out completely - wanted to inspect the board and it is more convenient this way.
Remove two T6 torx screws to disconnect ID Led cover. It's slightly yellow-ish. Cleaning did not help.
14) Release the tabs from behind to remove the disk. Use your fingers to slightly push several of the inward at the same time.
15) You probably can feel some sticky goo on the top of the disk with your fingers. Clean in (I used oil-eater with water), wipe it dry (I used cloth that comes with eye glasses).
16) Put everything back together. Don't forget to align arrows from step 12. Connect the battery, start the car. After the dreaded yellow AWD, break, stability control lights come up, turn the wheels all the way to the left, then all the way to the right. The messages disappear. It's been almost a week for me and the message has not re-appeared.
Great write up and pics, thanks. Two comments:
- I see a couple broken picture links at the bottom. Can you check those?
- Are you able to upload the pics directly to this site? That way if your host goes away we don't lose the pics.