I have had an intermittent DSC light on my dash for a few weeks. It would go away if I powered the car off then on. After it started to stay on permanently I had to have a go at sorting it, and using forums and INPA I diagnosed it to the SZL (steering wheel sensor). I could not find a guide for the E65 SZL removal/fix, but there were a few for other BMWs so I decided to have a go. The fixes suggested I would find an LED that would need a quick clean or a refurb kit that would replace an optical disc..
Neither apply to an E65.. Read on.
The SZL is the Steering Angle Sensor.
First, as always, you do this at your own risk.
Second, before you disconnect the battery, with the key out, extend the steering wheel as far out and as far down as it will go. This is so you can access and remove some screws in the cowling/clam shell so it can be removed later.
Third, disconnect the battery before you proceed, the air bag will be coming off and you don’t want it to go off.
I did not take photos during the initial stages, but it’s not difficult to work out what I am talking about. After disconnecting the battery, the steering wheel air bag has to come off. My E65 is a Sport model and has the 3 spoke steering wheel. The release procedure is different for the 4 spoke SE model and there is a YouTube video for the SE one. I could not find one for the Sport so this is how I did it.
There is only one access hole on the Sport steering wheel to release the airbag, it is at the bottom rear of the center spoke. I used a torx 15, but a small flat blade will work just as well. If you push the driver up the hole, what you are trying to do is locate a flat plate, then press a bit further against the plate which will pull in 4 release tabs that will release the airbag.
Through trial and error, I found that the driver can end up in 1 of 3 places when inserted, and only 1 is correct. The other 2 will just cause your face to turn red as you push against something solid and swear words to start.
In the first series of photos, I already have the airbag off so you can see where these 3 positions are, this way you can hopefully get an idea of what you are trying to do with the torx and can 'feel' where the torx tip is before you press the release plate.
WRONG. This will not release the airbag. The tip is forward of the black bracket.
WRONG. This will not release the airbag. The tip is on the bottom edge of the black bracket.
RIGHT. The tip is now on the far side of the plate and touching against the release plate.
Push against the plate and the release bars (compare the position of the bars in previous pictures) will pull in and the airbag will pop out.
Once the airbag comes forward, you need to disconnect the cable at the point where it connects to the steering wheel at the bottom. You may need a watchmaker’s screwdriver to release the connector.
At this point I removed the left and right side switches that control the audio and gearbox modes, each has a connector and 2 torx screws holding it in place. You can probably leave them in, but I took them out.
There is one connector that goes from the steering wheel (that you will be removing) into the SVL, again a watchmakers screwdriver may be needed to move the small release tab on the socket to release the plug.
Then use a 15mm socket to remove the steering wheel bolt. BEFORE removing the steering wheel itself, mark its position on the spline with a pen. There is a marker in the wheel and the spline anyway, but I put my own marker on them.
What you are now looking at is the top cover that sits over the SVL module, it pulls off easily.
OK, now more pictures..
This is what you will see at this point. The four switches need to come off, 2 torx screws each and pull off.
The SZL module is the whole unit that is in the centre of the steering wheel housing. Remove the torx 3 screws holding the SZL in place.
There are 2 screw covers on the top of the cowling that prise off, revealing 2 screws that can be removed. A third screw needs to be removed from the bottom cowling.
Once these 3 screws are out, the upper cowling can be manipulated off.
Now remove the lower cowling and unclip the steering wheel adjuster and the corresponding blanking plate on the opposite side of the steering wheel.
Remove the 2 connectors from the rear of the SZL
There are 3 catches that hold the fabric surround onto the SZL. Disengage these, and the SZL will be free to pull away.
The SZL unit.
The SZL splits into 2 main parts, the top circular part needs to removed with care. This part rotates around the fixed base. I noted warnings on other guides marking the position of the top part in relation to the base before removing it, as failure to do so can cause the unit to fall out of alignment and impossible to recalibrate. As it transpires the E65 SZL does not have the LED/ Optical setup, I could not see any of the alignment markings, so I just proceeded with care.
To split the 2 parts, release 2 clips on the inside of the center of the SZL unit.
Ok, at this point I was expecting to see an LED and Optical sensor as in the other guides. I then realised the E65 does not use a LED/Sensor set up. It uses potentiometers to generate the position of the steering wheel. You can see in the photo the 3 circular potentiometer tracks. The wipers for these tracks are mounted in the 2 rectangular protrusions on the inner ring that rotate over the tracks with the inner ring as it turns with the steering wheel. There are 2 wipers on each of the 2 blocks.
Clearly visible on the tracks were small bits of debris and fluff, especially under the wipers.
I suspect the wiper(s) were losing contact with the track causing the SZL to fail.
A few words of caution here :-
1. There seems to be some lubrication on the tracks, which must be there for a reason, so don't be tempted to clean it all off with alcohol, it may shorten the life of your unit.
2. When cleaning the crud from under the wipers, take extreme care. They are very delicate and if you bend them, you will be unlikely to get them back into their original shape. Don’t use anything metal to clean the wipers as you may cause damage. I used a cotton bud, but this has cotton strands, so I went on to use a lint free cloth.
It may have been possible to disassemble the unit more, and separate the wipers from the track to gain better access, but I decided not to risk it.
I reassembled and the error cleared, has stayed off and hopefully will not come back.
This is a good write up. Hopefully it fixes your issue. I have a 2006 E60. I THINK it has the optical unit. I get an szl fault like once a month or less. I'm just waiting for it to come on regularly before I try and clean mine. But glad its possible with the wiper style or led/light style szl
ASE and BMW Master Certified Technician
Just wanted to say thank you for this post!
I have an 08 750Li that the szl module would inevitably "fail" at some point every time I drove the car.
Using your post as a guide:
-I disassembled the column (I also removed the metal ring the wipers are attached to)
-I cleaned the tracks and wipers with rubbing alcohol
-I reassembled everything
And now I have NO szl errors when I drive!
Last edited by The Old Man; 03-22-2014 at 08:34 AM.
Oil comes from airbag spring wire, it is the reason why this sensor fails. Sensor has to be ideally clean to work. When oil pours to tracks, and sensor moves, wiper contacts will stick to track and will break.
- - - Updated - - -
Yes it is possible to take moving part off sensor, and its pretty easy, done enough carefully, nothing will break
Thx a great guide
One of my wipers has worn down , there is no contact anymore with the surface !
Going to order a new one and mount it in .
thx
You can use
Last edited by patrick S; 04-26-2015 at 06:03 PM.
Any guidance on where to order one of the wipers? I have the same issue, one of my wipers is completely gone
Old Thread , but can a SZL issue cause Dynamic Drive to go inactive? I'm having issues with the adaptive lights not working as well. Could this all tie to this?
INPA shows a couple of SZL errors so I know there is something wrong with it. It turns right back on after I clear it. Also would a new SZL need to be programmed in if its replaced? Thanks
Yes it can affect the dynamic drive.
I had the problem and sometimes dynamic drive warning about deactivated would pop up.
I got it 3-4 times pr year driving into the office garage, usually in humid cold condition in combo with turning fully left and then right....
I would not be surprised if it could affect adaptive lights as well , since it need to know the steering angle.
Thanks so much for this wonderful article. Thanks to this I was able to fix (hope it last) my wife's 08 E66. Not near the problem I thought it would be before reading this. Cleaned SZL and all seems well so far. Light was coming on within 1/4 - 1/2 mile max. Drove it 12 miles after repair and NO light !!!
Hi,
I am looking to do this repair on my BMW 7 series E65. Would it be possible to re upload the images please? Thanks
Great guide! I want to do this repair!
But the images are missing, because Photobucket has disabled third-party hosting. Could you please upload the images again? Or perhaps via Imgur (should be free)? I would be very, very grateful!
Help us grumman; you're our only hope! Please re-upload the pics!
Also need pictures!
guys to view the images use firefox browser and go to add ons and extensions then search for something called photobucket fixer or embed fix, download and enable. this extensions allows you to view all photobucket images just like you could before they got greedy and held everyone to ransom ( I really despise photobucket for this move).
Thanks for the write up OP I have a 2004 e60 and was expecting the optical disc and come across this style of sensor instead and couldn't find any guides to assist me in attempting repair. I gave it a clean although I think it was just a graphite coating to reduce friction and overall the unit looked in good condition, unfortunately it did not fix my active steering issues.
i wanted to say thank you for the info on "Photobucket embed fix" it works Great as my steering angel acting up also
Thank you for sharing this repair. I just made the same repair on my 2006 E65. No more SZL DTC's. I noticed that 2 of the wipers on my sensor were missing the fine brush like material. I cleaned the disc with Q-Tips and reinstalled anyways, just to see if it would make a difference. So far it has worked well. Thanks
No probs, i despise photobucket for their dick move holding everyone to ransom like they did, happy to see there is a free patch to fix it.
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