E39 540 DSC Light On NOT ABS!

Hi all

My e39 540 DSC light is permanently on. All the searches refer to the ABS and DSC light on, but mine is just the DSC light on. The car has recently had new front discs/pads/pad sensor, brake fluid, battery, climate resistor, but the light was on before that anyway.

A few other searches suggest various wheel/speed sensors, but the speedo works fine as does the cruise control and all other functions/features on the car.

Other searches suggest ABS module, but then surely ABS light would be on as well? ABS 100 % works, no other warning lights on, just getting a little annoying every time I put my foot down hard I chirp the tyres, not too bad in the dry, not great in the wet though lol. I had a mate pop round with a laptop & data cable plugged it in somewhere under the dash, no faults found! I'm baffled! Anybody with any ideas before I have to take car to the garage?

Thanks in advance

Is it possible you accidentally disabled it by pushing the DSC button on your MID panel?

Originally Posted by bobdmac

Is it possible you accidentally disabled it by pushing the DSC button on your MID panel?

I've pressed the DSC button several times but the DSC light is still on. Also reading the manual when the car is switched off, if working properly the system the DSC will be 'on' by default so the DSC light would be out when starting the car. Thanks for your help anyway.

Maybe it's a problem with the switch. I guess I'm hung up on this because it's hard to imagine the DSC function failing in isolation, without any other apparent issues.

There are at least 2 sensors that only affect DSC......steering angle and yaw rate accelerometer. The steering angle sensor error sometimes occurs after a front end alignment is performed.
Was your mate able to read the DSC module with his laptop connected? Do you know what software he was using? If your e39 has the underhood diagnostic plug you must use it, not the underdash connector, to read all modules.
The DSC light is also characteristic of having a used but uncoded DSC module installed.

http://forums.bimmerforums.com/forum...+code+used+dsc

Paul S
BMW CCA 69606

Originally Posted by pshovest

There are at least 2 sensors that only affect DSC......steering angle and yaw rate accelerometer. The steering angle sensor error sometimes occurs after a front end alignment is performed.
Was your mate able to read the DSC module with his laptop connected? Do you know what software he was using? If your e39 has the underhood diagnostic plug you must use it, not the underdash connector, to read all modules.
The DSC light is also characteristic of having a used but uncoded DSC module installed.

http://forums.bimmerforums.com/forum...+code+used+dsc

Paul S
BMW CCA 69606

Sounds like it could be the steering angle or yaw rate accelerometer. I wasn't aware there was an underhood diagnostic plug under the hood as well. Looks like it's a trip to the garage. Most garages where I live in the UK are quoting £60 just to read the codes, looks like I will have to pay up!

There are very likely other reasons also, my point was there are indeed reasons for only the DSC light to be lit, rather the the more common DSC/ABS/BRAKE light trio. Only e39's built before ~7/2000 have both the underhood and underdash connectors. Later US cars only have the underdash connector, not sure if these dates apply to the rest of the world.

Paul S
BMW CCA 69606

Good info, Paul.

Originally Posted by pshovest

There are very likely other reasons also, my point was there are indeed reasons for only the DSC light to be lit, rather the the more common DSC/ABS/BRAKE light trio. Only e39's built before ~7/2000 have both the underhood and underdash connectors. Later US cars only have the underdash connector, not sure if these dates apply to the rest of the world.

Paul S
BMW CCA 69606

My production date is 2000-04-07, so I assume I have both? Do you have an image of what the underhood connector looks like?

Look at posts #11 & 13

http://forums.bimmerforums.com/forum...d.php?t=907448


Paul S
BMW CCA 69606

Originally Posted by pshovest

Look at posts #11 & 13

http://forums.bimmerforums.com/forum...d.php?t=907448


Paul S
BMW CCA 69606

Cheers, nice and clear!

Took the car to the garage, the issue was the steering angle sensor. Garage reset it car now driving fine

Thanks for the feedback.
Can you tell us what garage charged you to fix?

Originally Posted by kingbob

Took the car to the garage, the issue was the steering angle sensor. Garage reset it car now driving fine

Originally Posted by pshovest

Thanks for the feedback.
Can you tell us what garage charged you to fix?

The diagnostic and labour to reset the sensor came to £79

*Update DSC light on again, ABS & Brake pad light on in yellow, car booked in garage for Saturday

I just went through the same crap and it ended up being my alternator.

*Update, turned out to be the offside rear ABS sensor £143 diagnose supply and fit

Thanks for the update. It would be nice to know what the ohms reading is for the four wheel speed sensors:
- How to diagnose the BMW ABS BRAKE DSC/ASC trifecta (1)

Here's mine, for example: