Mid dash ASC and anti lock lights stay on - need help

[PAFishman]

Just completed a full suspension rebuild on the 540 - upgraded to 540 sport springs and the 540 sport sway bars - otherwise stayed stock. Car is running fairly well as I get rid of the last few remaining issues. There is a slight hesitation after I come off the throttle when at highway speed (50-80mph).

After the rebuild, I had a brake sensor warning light on my dash. I thought I had a problem with the old front sensor when i reinstalled it. However, the ASC and anti-lock dash lights now come on and stay on as well. there ares no issues with my brakes that I can feel, the car is stopping like a 540 should.

I pulled the front left wheel to replace the brake sensor. I replaced the brake lining sensor (part no 34351179820) but still get the command line "brake lining see owners manual." Not sure what to do but check the rear sensor next.

While I was in there, I noticed that the insulation on the speed sensor wire that goes to the back of the hub has worn through. I will be ordering the part tomorrow but am wondering if that has anything to do with the dash lights and if it might be causing the slight hesitation on deceleration at highway speeds.
Thanks in advance for any insight.

[Layne]

It could easily be the sensor causing the lights. If the system can't sense all 4 wheels and find them to be logical relative speeds, both ABS and ASC have to shut down. That has nothing to do with your hesitation though.

[NikosX]

+1 Layne. Your wheel speed sensor is knackered.


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[PAFishman]

Thanks everyone. Removed the old wheel sensor today, spliced the 2 wires and the unit is working - at least the dash lights have gone out. Will check the rear brake sensor as I am still getting that command message. Any further ideas on that are welcome.

I found this thread about repairing and replacing the speed sensors in an e39. Very comprehensive and helpful:
https://www.bimmerforums.com/forum/s...l-Speed-Sensor