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Discussion Starter · #1 ·
Help

Has anyone had trouble with ASC light coming on (top of cluster)
As I have been rebuilding car for MOT over the last 6 months sometimes when starting her up the ASC light wont go out, now it wont go out at all. last problem to fix so I can get her back on the road.

I have replaced all the brake pipes and cleaned the ABS unit, have checked the ABS motor and its running nice and smoothly as have seen posts about ASC and ABS lights on due to motor

Have replaces the ASC switch as when it first started wiggling the wires to the switch seemed to fix it

Could it be air in the ABS unit causing the problem as I've been told it is a pig to bleed out when its all been drained even though I've bleed 1ltr of brake fluid through the system.
Are there any relays to check?
Could it be connected to throttle bodies control system?
 

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Have you connected diagnostics?

If you had an M62 engined 840 then INPA will certainly give you some fault codes from the ABS/ASC module which will pin down the problem. (But not sure whether 850 has the same compatibility - you might need the ADS cabled version of INPA??)

Not saying that yours is the same cause but I had ASC light on (on its own - usually it comes on when ABS is having a hissy fit in a show of 1970s trade union unity - "one out all out")

The INPA showed that the ASC servo motor which closes the throttle when it senses wheelspin was not working - replaced it (it is a part also used in other models with different length Bowden cables) so got one from a 3 series cheap on eBay, swapped the cable over and that fixed it.

Again - your 850 may well not have that servomotor?

Diagnostics is your friend, you can go potty swapping stuff in an effort to fix things. USB cable, OBD 20 pin converter and a cheap XP laptop has been the best £100 I ever spent.

If you are anywhere close to me (Newbury Berkshire) you are welcome to borrow my laptop and see if it will talk to your car and I think in a fit of silliness I bought a spare servomotor as it was going cheap so again you would be welcome to have it and swap it out)


John
 

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Discussion Starter · #4 ·
Thanks for the reply,
Looks like I'm going to try and find diagnostic software & Hardware.
Have looked about and for the age think its ADS cabled version of INPA that I need to find
Thanks for the offer of using your laptop but I'm in Essex

Grahame
 

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Hi Grahame

Have a look on ebay for an old laptop with a serial port and windows Xp..... the dell d610, 620 and 630 are popular. With a bit of patience you should be able to get one on an auction for about £30-40. Just make sure it has windows xp installed.

Next get the ads cable from this guy in the USA either the diy version

Tiny ADS Interface

or his ready to go one

Tiny ADS Interface inside 20 pin connector

a different version available here (but i cant vouch for this one)

BMW INPA / Ediabas OBD & ADS Interface

As for the software i have pre configured Dis and inpa saved to my dropbox account which I'm happy to share. just send me a pm and I'll forward the links..... It was kindly shared with me from members of this forum and the .com site.

It all works on my 97 840 and should work on your earlier 850. Lots of other diagnostic possibilities but this route worked for me.

Good luck




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If it were a wheel sensor you would have both the ABS and the ASC light on - which you haven't. As you have an 840ci then you have a Bowden cable operated secondary throttle butterfly which controls engine power. If you just have the ASC light on then this is the system that is faulty.

And the usual cause of this fault when an engine has been fiddled with is that either you have leant on the Bowden cable and put a kink in it, or you have accidentally swapped over the connections for the ASC throttle position sensor and the main throttle position sensor - this happens all the time as the connections are exactly the same. In the picture below you can see that I have added a cable-tie temporarily to the ASC Bowden cable to re-attach it to the oil filter canister:



,,,because I had leant on the cable, broke the cable clamp and put a kink in it which illuminated the ASC light
 

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Discussion Starter · #7 ·
Thanks Timm,

Was thinking the same on wheel sensors as when I replaced the rear sensors I had a moment of madness and turned the ignition on and got the ABS light up

Unfortunately I have an 850 and it doesn't have a ASC Bowden cable as I have 2 electronic throttle bodies one on each bank

Do you know where the ASC module is or is it built into the ABS module

thanks
Grahame
 

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Hi hulkster

If the ABS control unit includes the ASC control and you want to try a fresh one, I have one you can have for free ( for the postage or you can collect for free)

Saw it going cheap on eBay at £75 and before I knew that the 850 and 840 had different systems (it was the early days of working on my wife's E31 and I didn't know any better!) I bought it

In terms of location I would assume same as 840 under the carpet on the passenger side (UK RHD) sill

Regards

John
 

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Discussion Starter · #10 ·
Looking on real OEM and the ABS and ASC are one control modual
There are 2 types ABS/ASC or ABS/ASC+T what does the T stand for is that the active suspension option?
 

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Automatic Stability Control plus Traction control. ASC+T was just that generation before DSC (if you see what I mean). Traction control got 'cleverer' during the lifetime of the E31 so you need the bits for your era of car
 

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Hi Grahame

Have a look on ebay for an old laptop with a serial port and windows Xp..... the dell d610, 620 and 630 are popular. With a bit of patience you should be able to get one on an auction for about £30-40. Just make sure it has windows xp installed.

Next get the ads cable from this guy in the USA either the diy version

Tiny ADS Interface

or his ready to go one

Tiny ADS Interface inside 20 pin connector

a different version available here (but i cant vouch for this one)

BMW INPA / Ediabas OBD & ADS Interface

As for the software i have pre configured Dis and inpa saved to my dropbox account which I'm happy to share. just send me a pm and I'll forward the links..... It was kindly shared with me from members of this forum and the .com site.

It all works on my 97 840 and should work on your earlier 850. Lots of other diagnostic possibilities but this route worked for me.

Good luck




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I am interested in having a link to download the INPA software. I already bought in Germany the round connector interphase to serial port, but have not been able to configure and read correctly with the INPA they provide the connection to my bmw e31 840 1994.

many thanks in advance
l.peterssen
 
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