ASC light is on

[Franks528i]

Okay a week ago the asc light turned on and wouldnt turn off, the next time i drove it it was off then when I got onto the tollway it turned on and has been on since (about 5 days). the car drives okay. i have no check engine lights. What are the possible problems. could it be a variance in tire pressure (high hopes), bad wheel bearing or sensor? please help

[///M Power]

Wow an ASC light? wtf? lol srry ill probably get it if you take it out of the acronym form, im just really lost right now.

[LOS]

It means you have no traction and the problem could be anything from brakes to suspension issues.

LOS

[Franks528i]

well the last few days, probably more, my front struts feel like they might be going out. could this cause it? how would bad brakes cause this light to come on?

[LOS]

Sorry, is not really the pads, could be the fluid. If you just flushed it and have a leak or air bubles in the system, etc... Check the fuses as well and clean the suspension components. lookf for anything that is loose in the suspension.

struts??? if we're talking about traction... maybe that's it, but the whole front end of the car would feels loose (a floating feeling when you make turns). I'll keep reading the repair manual...

LOS

[Franks528i]

thank you for your help.

[02bmw540isilvergreynav]

Frank, I am sorry to tell you it is your transmission slipping. I have a 97 with the same problem right now i have been to busy to deal with. I just went ahead and bought a new car.
I am gettng it fixed to trade in for my wife's new car instead so I am having a used tranni put in for 2000. rebuilt would be 3700 according to the local guy. I am having one shipped to aamco since I am not keeping the car. I did notice my fluid was low so when I get a chance I will try that first but I don't think it is going to help. I think we are both screwed! I will let you know if I find different.

[Franks528i]

thanks for the potentially bad news. i really hope thats not my case.

[TMac325is]

it is possible to turn the ASC on and off manually isnt it?

correct me if im wrong, but on my 3 series its the little button infront of the shifter.

does anybody know if there is much of a difference if you turn it off and drive around?

[EXtech]

Typical problems: faulty wheel speed sensor, faulty ASC control unit or in the rare case mentioned above, a transmission problem. Generally if the transmission is failing you will have noticeable slippage and/or usually trans program fault codes. There is a small possibility if it's a transmission issue that it is the output speed sensor inside the trans. It's more likely that you have one of the other two issues occuring (faulty ASC control unit or wheelspeed sensor). Take it to your local shop and have the fault codes checked, this is the only way to know for sure. I wouldn't procrastinate though. Good Luck !!

[Franks528i]

thank you again. what does it cost to have the car scanned at a dealer? i can fix it myself but I just need to know what it is.

Thank you

[LOS]

I'm sorry it too so long to get back to you... EXTECH is right on the money on his/her reply!! And like he/she said, the only way to know it's to take it to the dealer and read the codes.... which should tell you what the problem is. Hopefully it will only be a sensor... Good luck... The dealers here in L.A charge around $125 just to look at the car... It all depends where you live

P.S KEEP US INFORM ON YOUR FINDINGS... IT WILL HELP THE REST OF US.

LOS

[machinehead]

Was there ever a fix/outcome on this?

The ASC light has been on since I bought my 525 e34 last August. ABS works fine, as does the speedo. The actuator cable is not broken and is adjusted per spec. and the throttle position sensor has been replaced, as has brake fluid & the pads are fine, all tyres even, same size/brand.

When engine is first started (not in gear) the light is off and can be turned on and off via the ASC button. Now, give the engine a blip of the throttle (over 1,100 rpm) and the light comes on and stays on - because of this I cannot see its an ABS sensor, and must be a faultly ASC unit as far as I can deduce.

Any thoughts? Are these simple to replace? Is a 2nd hand one likely to be good or are the units prone to failure?

[BeelZibub]

ASC+TRACTION works off of the ABS sensors on the rear wheels, hence if an ABS sensor gets damaged/fails or is simply disconnected your ASC light will usually come on - But as said above getting a code scan is the best way to go.

[k2c69n]

Yeah , i too have the same probably it comes and goes periodically.. I am going to take it to get it fixed once the weather gets a bit nicer.. I know mine doesnt have to do with the transmission at all.. mine works perfectly.. but those abs sensors are pretty pricey.