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DSC, GWS, SZL and other issues

6052 Views 4 Replies 2 Participants Last post by  toxic_bimmer
Problems started a couple of weeks ago when all of a sudden the DSC and (!) warning lights came on. They pop up quite sporadically, but tend to have several patterns.

Pattern #1: was driving out of the basement parking lot, incline was around 30 degrees, speed under 20 kmh. Had to stop the engine and pull the key out, that solved the problem, for some time. Happened again a couple of days later under the same conditions.

Pattern #2: Moving in a straight line but catch a bump or a pothole. Normal cruising speed of around 60 kmh.

Pattern #3: Speed under 30 kmh, make turns, either direction.

Typically, I get two messages:
- 1st shows the shifter and says Start assistant inactive
- 2nd says Drive control system! Drive moderately
- some other variations of drive errors, while saying that vehicle should be driven carefully.

Indy's opinion
Scanned it, said that there were some errors with SZL, DSC and DWS, but no need to change them. He just topped the steering fluid and said that there is a leak somewhere in hydraulics system. In the end, that didn't help. just that (!) warning light now comes in orange (used to pop in red).

Official BMW dealer's opinion
- SZL and DWS errors cause the problem. Just an error, no need in immediate change, however, it is still recommended to change SZL and DWS. Preliminary cost estimate is about 2K US, but can go up if more parts are needed to be replaced.

I first decided to ignore it, since all bimmers have some electric gremlins since the day 1 they are off the assembly line. But the car started to develop yet more issues, most likely due to faulty DWS or something else.

1) Clock resets on its own
2) Put in Park and stop the engine, electrics die, can't pull the key fob out, clock and date resets. I suspect that GWS can't send a signal that it has been put in Park, hence the locked key. Eventually the system backs to normal and spits the key out. Couple of times.
3) All four windows or just driver's one roll down by 2 inches or so when u shut the door. no lock button pressed yet. Couple of occasions.
4) and when those DSC and (!) warning lights come up, audio sound keeps jumping and skipping tracks.

Has anybody experienced similar problems? Thinking of getting it to a dealer to have those
parts replaced. Looks like a big ticket... Could there be other problems beyond those two popped on the scanner?
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Hi guys, I dropped off the car (08 528i) at the BMW service center couple of days ago, have to replace the GWS (gear selector switch) along with SZL.

1. My question is why do GWS and SZL break down in the first place?

I remember I was driving it couple of weeks ago in DS mode, parked it for couple of mins, and when came back forgot to switch the lever back to D mode (as I used to drive X6 and several other bimmers with e-box and as far as I remember they always returned the shifter back into D mode automatically). The car wouldn't start and I was pushing that shifter several times forth and back trying to "unstuck" it, until I saw that it was still in DS mode. Switched it back and she started just fine, but the problems I wrote above appeared. In the end, had to replace the whole module.

2. So could it be me? or it's just a normal wear?

Just asked an adviser at the official BMW service center about possible reasons and got the most stupid answer one would expect from someone who performs the service and is supposed to know at least the common causes for specific parts to break down.

So, the answer was... "We don't know the cause, we just scan it and do as computer tells us to do"... And to make him tell this I had to repeat my question for 4 times, at least: "What would you, as a specialist, say to be the most common cause for those modules to fail?" I guess, he was really baffled by this simple question...

seems that the "good" services is limited to getting you a cup of coffee or tea... Isn't BMW supposed to hire people who actually know something about cars?
Bummer... not sure on the GWS replacement, but the SZL units are sensitive. When my car was being diagnosed for the sport-auto-trans retrofit, the SZL unit failed after removal and replacement by the dealer and was replaced under warranty. There are parts of the unit (steering angle position sensor for example) that have been known to fail on occasion, and there may have even been a service bulletin/recall on early years.

As for some of the other symptoms you were experiencing, they sound more like a failing battery -- which can lead to a ton of 'red herring' electronic errors, possibly including the original ones you were experiencing. You may want to confirm the battery is good before you resort to the more expensive replacements. My battery had to be replaced earlier this year on my early build '08 as I was receiving clock resets and occasional other warnings/errors that came and went.

Let us know how it works out for you.
Thanks guys for your replies! Helped a lot to understand what I'm dealing with!

Got the car back on Friday, GWS and SZL replaced. Drove around 100+ km, well, so far so good. Looks like it solved the problems, but again, will have to drive it a bit longer, as the problems I experienced, appeared very randomly, so knock on wood

To sum it up:
- Cost: around 1.9K (parts, labor and programming)
- GWS replaced (including the shifter itself, I asked them if they could have replaced the module only, to save the cost, but BMW said that they replace it as a whole, mmm... well at least I got a new shifter, leather at the back of it feels smoother strange, but OEM shows that you can actually buy them separately...)
- SZL replaced, as a result, may be it's just my false feeling, but the steering feels a bit tighter, may be I'm wrong.
- No previous electrical problems... hope that it will stay like it (looks like the faulty sensors caused all those glitches)

Will keep you updated as it goes.
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