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Re: More findings

What do you mean they "couldn't dyno"? It wouldn't let them spin up the rear wheels without intervening? This doesn't make any sense. Our province and lots of states have inspection programs which require rolling emission tests on a two-wheel dyno. Do these randomly occurring E46s get a pass because the car acts weird when the authorities try to put it on their dyno? I'd think not. Only AWD vehicles get to do an idle-only test if the facility doesn't have a 4 wheel dyno or rolling road. Every other vehicle of every brand is expected to do the idle and rolling test.

The last time I had an e-test I don't think the place I went did anything with the ASC button. The software seems to have logic built in for this to take place since BOTH front wheels are stationary and BOTH rear wheels are turning equally. When they brought the car around the ASC warning light was on. I was about to ask him about it and he finished my sentence ("traction control light on?") The guy said that was normal and it would clear as soon as I exceed 5 or 10 mph (I forget). He was right, just after pulling out of the parking lot the light went off. This wasn't a BMW shop and he made it sound like he sees that sort of thing every day from all kinds of cars.

I agree that software plays a big role, but I'm skeptical that BMW would change the design practically from month-to-month making inspections, tests and dyno operations impossible on some and work fine on others.

Interesting... Anything is possible I guess.

More findings

I originally thought this was for cars with ASC+T but it seems it can be ASC ASC+T or EVEN DSC. From what Ive read it looks as if software plays a big role in determining if the button trick works.
On dyno days some e46's let you turn off the ASC with one click, others needed the 10 sec trick. and a couple couldn't dyno at all no matter what they did to try and FULLY turn off the ASC or DSC. They would turn it off and when they reached around 20mph the ASC/DSC intervened. After a dealer software update they were fine.


This is from e46 forum guys

Functions of DSC button (E46, Z3)

The DSC button features two functions that can be set by pressing the button for different length of time:

Button pressed briefly (< 2.5 s):

Only the yawing moment control of the DSC is deactivated. The ADB and DBC functions remain active.

A higher slip rate is permitted up to 70 km/h for the purpose of improving traction. ASC uses different slip thresholds.

The DSC light is on.

Button pressed for longer (>2.5 s):

All ASC (ADB) and DSC (GMR and DBC) control functions are deactivated.

DSC light and general brake warning light (yellow) ON This mode is mainly intended for roller dynamometers and service purposes.

By pressing the button again, the system reverts from the respective function to normal DSC function. It is not possible to ”switch” directly from one function to the other.

Andreas
Queens NY
BMWCCA# 186796
86 325es (wrecked by careless driver)
87 325 300k (project for life)
00 540is 6spd 180k (daily driver)

Probably a trip to the dealer

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
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NOS Progressive 2 Stage Controller with port injection
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DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
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G-Tech/Competition Pro Data Logger
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Would a scan identify the fault ?

Wondering whether a lap-top type scanner software would find the fault or if it means a trip to the dealer ?

my oct 99 production 2000 528 works as described

in manual. Press the DSC button and the system is deactivated and the yellow triangle lights to indicate such. Supposedly holding button down for 10 seconds completely deactivates the system.There may be two components of the the system.

Jay Gans 2000 528 MT Non-sport.Titanium Silver, Grey Leather. Premium Package, Cold Weather, Fold down seats. Oct 99 production.ash try mod so not bone stock. CD changer. Garmin C510 Nav..Honda CH150D scooter

Re: The code is written2 fail in a non-fail safe mode?

I guess so... The important thing is to illuminate the lamp and tell the driver that something is wrong. Most of the systems on the car seem have a programmed action if the switch fails closed. The windshield washers do too.

I remember thinking the same kind of thing with the airbag system on my Porsche 968. I stupidly turned on the ignition once with the instrument cluster removed. The airbag computer saw that the airbag warning light wasn't working, so it disabled the airbag system and illuminated the airbag light (which "wasn't working"). I had to get it reset by a dealer with the tool.

The only part of that which made some sense is that Porsche uses a "master caution" light which is large and right at the top of the cluster. It draws your attention to look at the myriad of other warning lights which can be small, dense and tightly packed when a master light exists. So, if the airbag warning lamp was indeed burned out, the master caution would also light (even though the airbag lamp wouldn't be lit) and you'd go to the dealer for service and they'd figure it out.

I USED to be able to do so as well...

After replacement of the rear wheel speed sensors (each side) the functionality of the system changed to what I described above.

i'm confused?

I can turn the ASC on and off in my '99 528i by pressing the button.... so what does holding it down do?- Nano
'91 318is
'99 528i
'05 BMW R1200GS
'98 Jeep Cherokee lifted
'07 Titan SE 4x4 Offroad

The code is written2 fail in a non-fail safe mode?

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
Passport 8500 X50, Escort ZR3 Laser Jammer
G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
PIAA Driving Lights
BMW CCA Member Boston Chapter

This isn't about ASC/DSC

The "hold the button" thing isn't a special disabling of ASC/DSC, it's just the way the programming is written in case the button fails closed. AFAIK, it isn't a super-secret extra-disabled mode.

Turn engine off, then restart it will activate DSC

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
Passport 8500 X50, Escort ZR3 Laser Jammer
G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
PIAA Driving Lights
BMW CCA Member Boston Chapter

Theres a trick to fully disengage

Im pretty sure you hold the button for 10 seconds and it fully disengages ASC. BUT you have to power cycle the car to turn it back on. Im not sure if that means turn the car on and off or disconnect the battery for a few minutes.

Ask around cause im not 100% sure on how it goes back on since i have DSC

Andreas
Queens NY
BMWCCA# 186796
86 325es (wrecked by careless driver)
87 325 (project for life)
00 540is 6spd (daily driver)

I have been experiencing a similar situation..

My traction control works as it should on slippery surfaces however I am unable to disable the system (allow the wheels to spin freely) Also, when I push the ASC button the light on my dash does not stay illuminated. I have a 2000 528 auto. The dealer believes that at some point during the E39 run, BMW changed the way the system functions from on/off by way of the button to on/partially on. Not sure I buy into that explanation. I too am faced with that occasional situation that warrants having the rear wheels free to spin without interference. Not sure if I've helped but I can at least empathize and wait with you for someone else to input...
Greg

ASC light never on - kind of long

I have searched the archives here and elsewhere and think I have a new ASC issue.
I recently bought a 1999 528 with 78k mi. I also have a 98 528 with 188k. The ASC on the 99 did not work (couldn't get out of my snowy driveway recently), but the dash light was not illuminated and the ASC switch had no impact.
On my 98 while driving, the light will flicker when I hit a patch of ice and the ASC automatical modulates the speed until traction is re-gained. The dash switch will disengage the system and turn on the light as it should.
I took the 99 to the local indy to get scanned and they said it was the ABS module. I had it re-built by BBA disconnected the battery and re-installed, but the ASC still did not function, nor did the light work. I brought it back to the indy who re-scanned and initialized the steering angle sensor. I picked it up and the ASC does seem to function, but the dash light still does not work and the switch doesn't seem to affect it. The indy suggested the switch was bad, but didn't have any codes to support his diagnosis. It was 5:30 pm and I didn't want to belabor the point so I have been driving it since. The lack of a working ASC light still bothers me though, since I was used to how it functioned in the 98 and it gave a little piece of mind when driving through the many snowstorms here in Maine. Has anybody dealt with this issue ? Suggestions ?.

Thanks !