540i DSC light permanently off....

[damomonster 0]

Hi everyone..

New to the forum but really needing some help.. I've very recently picked up a '99 540i.. I've got all the receipts etc for the car but as with anything you get at a good price theres usually some things to fix.. I've been hammering google and I can't get to the bottom of this though..

The DSC button in the console seems to do absolutely nothing.. I just can't get the light to come on with any combination of pressing or holding.. The ABS seems to be working fine but I can't control the DSC.. And then I noticed that there are two wires leading to the ABS computer that have been disconnected.. I don't know if they're related or not and have attached a pic if anyone can shed any light on what on earth they were supposed to go to?

I had a local auto electrician run a scan on the car and the computer reported something along the lines of Code 58 - Can open circuit to AGS..

So if anyone can help it would really be appreciated as the local mechanics don't normally have a lot to do with BMWs..

Cheers,

Damo

[andrewm 236]

Yeah that looks pretty suspect - the ABS unit is the DSC aswell, probably find there was an issue with DSC light staying on so someone just disconnected the appropriate wires hoping a WOF inspector or buyer wouldn't pick up that it didn't come on at all at startup. Try find a pin out on the net for the e39 plug.

Would also check glove box and boot fuses if that doesn't fix it incase someone pulled them, I cant remember where the appropriate fuse is.

Edited June 2, 2016 by andrewm

[will 169]

It will have both an ABS and an ASC/DSC warning light. The inspector will be watching for the ABS light to illuminate and then go out, showing that the ABS system is passing it's initial test on startup. He will then check that it stays off when driving. The ASC/DSC light should only illuminate if you switch off the ASC/DSC (if this feature is present, which I doubt your e39 will have), or flash on/off when the ASC/DSC kicks in when driving. The warrant inspector will not normally check this light is working during the course of a normal inspection.

The ASC/DSC light on the dash is connected to the ABS/ASC/DSC pump plug at pin 31. Should be a blue/brown wire.

What are the EXACT colours of the 2 wires that you have in your fingers?

[aja540i 1906]

Is the dsc working?

[dkonsta1 109]

Did you ask the previous owner what's the story?

Sent from my SM-G925I using Tapatalk

[andyb184 7]

pull that big plug connector going to the ABS/DSC control module and trace those 2 wires...it's hard to say without knowing the exact color codes as Will mentioned.

Edited June 3, 2016 by andyb184

[damomonster 0]

Hey everyone..

Thanks SO much for the replies.. I didn't get notified that anyone had replied so sorry for the delay.. OK, so here's where things are up to..

The two mystery wires are actually for a pump on a headlight washer tank that is missing from my car.. My car has the jets built into the front bumper but the cleaner tank and the attached pump are both missing... I figured this out by looking under the hood of another E39 540i which had all that gear still in it..

Of course that doesn't help with the DSC mystery... So... The ABS light does come on when the car is started and then goes out after a few seconds, basically like it should. I think the ABS or something is actually working because on wet grass or similar you feel the car braking or cutting power to the wheels (sorry not quite sure how to describe it but I'm sure you'll know what I mean)..

But, pressing the DSC button does nothing on the instrument cluster.. And I don't really know how else to test it.. BUT I'm starting to think it might actually be the cluster that's got some funnys instead.. When doing Test 2, the ABS light works fine, but that DSC Light and Traction Lights still don't come on.. On top of that, i've now noticed the Fuel Gauge doesn't reach full, even in Test 2 - it stops at about 3/4's.. And test 9 is coming up with Phase 1 some I'm thinking all the fuel gear is fine, just the gauge.. And finally when I put the car on the local auto electricians scanner, the Instrument Panel had some BDF4 error.. which I have no idea what it means but he said it translated to an internal error of some description.

So, if you're still reading.. Am I best to take the instrument cluster to a BMW dealer at this point or is there anyone else you guys would think would be better (and probably more affordable?)

And thanks again for the help so far, I honestly do appreciate it

Cheers,

Damo

[damomonster 0]

Oh.. and yes, I've checked all the fuses, they're fine too