Traction won't disable for emissions test

[Spider Whistle]

So I took my car in for an emissions test on Saturday, and when they pulled it off the dyno in about 2 minutes, I thought great, it must have passed with flying colors! Not so...
They gave me a form stating that my traction control would not turn off, and they could therefore not test it.
After I left, I confirmed that neither pushing or holding the button does anything. My car is up for renewal, so I've already passed the time when hitting a rapid screen would have been an option, and when I called this morning and spoke with their tech people, they confirmed that there is no way to test the car unless the problem is corrected.
I've literally turned traction off maybe 3 times in the 6 years I've had the car, so the thought of perhaps having to dump a pile on money on something just for a 5 minute test isn't sitting well.

Anyone have any thoughts on where I might start with this issue? There are no error lights on the dash, though I should mention that I do have a freshly rebuilt ABS module, so I can't help but wonder if the 2 things could be related.
To some of you this may be an obvious fix, go easy on me though, I'm not terribly experienced with electrical type issues. I do have a multi meter though, and I can follow instructions.
I did search a bit for this, but I couldn't find anything related to the switch failing to function.

Thanks for any assistance!

[1999 540i m]

Super easy, pull the abs module plug at the smog shop

[Spider Whistle]

That was actually my first though too, I just didn't know if the resulting codes/lights would cause them to not be willing to test it.

[geargrinder]

Read codes. See what it says. There could be codes despite no lights.

I dunno about a 530 but on MSS54 I know "dyno mode" is an entirely different thing than "traction control off". You can turn DSC on/off all day, but the car will still limit RPM in a dyno situation.

Clearly something is wrong if you've done this every year with no issue and now suddenly it doesn't work...

It might be as simple as the wire for the button has a bad connection, since teh ABS module was recently replaced. Or you used a sh17 place to rebuild it and the replacement module is borky - did you use BBA Reman or some other reputable place, or did you use "Lefty & Busters House of Cheap eBay Rebuilt Modules"?

[Spider Whistle]

Took the car to a buddy's house last night and used his code reader, and surprisingly couldn't find a single thing. I used Module Repair Pro for the rebuild. Not sure how they're viewed by the community, but I got 5 years out of the first rebuild they did for me, so I figure that's not too bad. I'm really thinking/hoping the lack of codes may point to something as simple as the switch. So I went ahead and ordered one from eBay last night. Fingers are crossed...

[geargrinder]

ERRRRR WUT? I DEFINITELY wouldn't have jumped to that conclusion / parts canon yet. My suggestion was check the connection/connector first.

Wiring diagram says a DSC5.7 car has the switch appear at pin 27 of the ABS/DSC module. Test that pin for volts and see if it changes when you press the button. It looks to me like it should be 12V / 0V from the wiring diagram but thats the kind of small detail that's not always reliable. If the pin is showing voltage switching while disconnected, then plug the module in again and try to 'back probe it' with the ABS/DSC connected. If its still switching fine then, then I like the idea that that rebuilt unit is borked and you need Lefty and Buster to send you another one. Seems WAY coincidental for it to have happened at same time. And given the switch button is not a high-failure part, way to coincidental for the switch itself to be my first (or 17th) suspect. Wires or module would be way way in front of that.

FWIW BBA Reman is lifetime warranty to orig purchaser, so, if you'd gone that way, this one (probably would not have broken in first place... but... if it did...) would have been free. Bridge over the water that flows under it tho', so... movin' on...

[edjack]

Strange: my car has been on the dyno for the last several smog tests. I was unaware that the station may have deactivated the ABS, via the button. However, driving away, the ABS light was lit for 20 ft or so before it went out.

I attributed that to fact that the rear wheels were spinning, and the fronts were not. But it may be that later cars had different control firmware.

[JimLev]

Same with my '00 when I had it dynoed. Front wheels not turning, the ABS light came on, when off as I left the shop.

[Spider Whistle]

I only jumped to the parts conclusion because that particular part is widely available super inexpensive ($12 shipped), so I figured it was worth a shot.
I agree, very coincidental timing here. Though to be fair, I haven't tried to disable traction in at least two years (since the last test) so it could have happened at any point.
Unfortunately this is the first I've heard of BBA, price is certainly comparable to where I went, so it's too bad I didn't know about them before. My place offers a lifetime warranty as well, only when I reached out to them regarding the failure a few months ago, I found out that their warranty only covers the particular issue that was repaired, not the overall function of the ABS module.
If it turns out to be the module again, I'll be damned if I'm giving Lefty & Buster another penny. If it comes down to that, I'll go with BBA and have done with it.
I'll try to do the testing you recommended, thanks for the advice!

[Spider Whistle]

Well, right you were- snot the button, the new one didn’t change anything.
I probed pin 27 and noted the voltage change when I pressed the button. I’m not sure how to test it any further than that though. It seems like I’ve confirmed it’s good up until the ABS module itself, but there doesn’t seem to be anything to back probe since it’s all inside the module. I emailed BBA and am awaiting their response. It’s looking like I’ll be out of luck getting the guy who repaired mine to honor the work, because he just keeps insisting that if there aren’t any codes, there can’t be a problem.

[geargrinder]

Yep. Knew that was gonna happen.

"no codes no problem" is more proof that "Lefty & Busters House of Cheap eBay Rebuilt Modules" doesn't know what they are talking about. For sure sometimes even full Trifecta cars have no codes. That's one of the indicators to perhaps bite the bullet and get the module rebuilt. Hopefully BBA has something to say (although it might be 'send it to us'...)

[jmc1590]

I'll ask the question, does the ASC/DSC (Traction) light come on when you start the car? (i.e. - the initial panel light up.)

[Spider Whistle]

It does indeed.
I’ve read that there seems to some question as to whether it’s necessary to program a new ABS module to your car, have any of you had experience with that? I’m starting to wonder if if may be better to just get a different module at this point, considering this would be the third time mine has been cracked open. There’s a junkyard on my drive home that has several e39s on the lot, wondering if it’s a worthwhile gamble to go look for one there.

[1823alex]

It does indeed.
I’ve read that there seems to some question as to whether it’s necessary to program a new ABS module to your car, have any of you had experience with that? I’m starting to wonder if if may be better to just get a different module at this point, considering this would be the third time mine has been cracked open. There’s a junkyard on my drive home that has several e39s on the lot, wondering if it’s a worthwhile gamble to go look for one there.

If you put in a module that isn't programmed, your ABS will work and the ABS / BRAKE lights in dash would go away if you had the trifecta lights. However if uncoded, your traction control will not work or be active at all and the light in the dash will stay lit.

[Spider Whistle]

That may be just what I need to pass the test... lol
I could just throw my old one back in afterwards.

[Spider Whistle]

Ok, so I went by the junkyard on my way home last night, and thanks to bs traffic I ended up there with only 5 min before closing. I managed to locate the e39 and yanked the module. Physically it's identical to mine, but the part numbers are slightly different. I had crap service on my phone, and they were going to close as I sat out there trying to research the number. So I said screw it, let's see what they want for this thing. When the dude told me $14, I figured I didn't have much to lose, even if it's not compatible I can probably get at least that much on the core if send it in.
After going home and researching a bit, I'm thinking it's not going to be a match, though I'm not totally certain. I'm kicking myself for being in such a hurry that didn't stop to get more info from the donor car, as that surely would have helped. Perhaps someone here will know if this is compatible?
existing module
34.52-6 758 971
0 265 950 002
new module
34.52-6 751 500
0 265 950 001

[vinyldude]

Ok, so I went by the junkyard on my way home last night, and thanks to bs traffic I ended up there with only 5 min before closing. I managed to locate the e39 and yanked the module. Physically it's identical to mine, but the part numbers are slightly different. I had crap service on my phone, and they were going to close as I sat out there trying to research the number. So I said screw it, let's see what they want for this thing. When the dude told me $14, I figured I didn't have much to lose, even if it's not compatible I can probably get at least that much on the core if send it in.
After going home and researching a bit, I'm thinking it's not going to be a match, though I'm not totally certain. I'm kicking myself for being in such a hurry that didn't stop to get more info from the donor car, as that surely would have helped. Perhaps someone here will know if this is compatible?
existing module
34.52-6 758 971
0 265 950 002
new module
34.52-6 751 500
0 265 950 001

If the back side of the module looks identical to your old one, I.e. there’s a same number of those solenoid looking things, I think you’ll get it to work after recoding. Like others said it does not have to be an exact part number match necessarily.

[Spider Whistle]

We have resolution! I just got back from passing my test, and thankfully won't need to think about that place for another two years.
The module I picked from the junker immediately displayed the trifecta of lights, and would not disengage traction. I mulled the issue over for a week, wondering if that was a result of not getting the module coded to my car, or if it was my luck that I grabbed a bad module. I was ready to throw in the towel and take it to a shop, but I figured I'd look around one more time to see if I could find a donor car more similar to my own. Found a 2002 525 yesterday, and the part number was a perfect match for mine. I crossed my fingers and threw it in... no lights and the dsc button worked!!!
Now we'll see what the rebuilder says since I've got irrefutable evidence...
Thanks for the input, everyone!

[geargrinder]

Cool. Yeah the first JY module prob was coded for a different something or something... or maybe was just pre-trifecta'd.

Congrats on gettin yer sticker!