E39 Intermittent ABS & Traction Control Warning

[taxboy]

I've got a 2001 E39 520SE auto. 6 months ago just as I pulled into my local indie for its service I got the warning light come on for ABS & Traction Control. He plugged the diagnostic control in & decided that the sensor was duff & replaced it.

I'm now starting to get the same warning appear intermittently again but it only seems to occur when the car is hot after a longish journey 30+ miles & then I restart the engine.

I know the ABS works (after the recent cold spell !!) so any ideas of what might be wrong or should I just live with it

TIA
Andrew

[Fox-]

Wheel speed sensor. There are, obviously, 4 of them.

[TheEnd]

Best to get diagnostics done again. It could be an intermittent connection on a wheel sensor, but you won't know which one.

[< FORZA WEST]

3 common faults with E39

Wheel speed sensors-they eat them

Tyres unevenly worn ie one at 5mm one at 2mm

ASC control unit - sporadic light on, always seems to list a wheel speed sensor, happens when hot,

[Fox-]

Forza, please move to Devon so I can use you for all my E39 repairs. Is there anything you don't know?

[< FORZA WEST]

LOL, i still havent quite worked out how the universe was created but im almost there.

[taxboy]

Thanks for the help with this - much appreciated. I expect it'll be a rolling programme of getting the sensors replaced !!

[Don1]

Just as an FYI, same thing just happened with my X5. Speed sensor.

[taxboy]

I finally got to taking my car in because I had the ABS sensor changed & still got the warning light when the car got hot. The indy initially rang me to say after diagnostics would need a new control unit as it was still showing the same sensor needed replacing & this was OK & would take a couple of days to get. When I went back to pick the car up he said he had another look and noticed some oil in the loom & wondered if this was the problem so rather than spending a fortune on a new unit he had cleaned it out cleared the faults out road tested it and seemed OK. As I was going on holiday he said let him know how I got on. A day later sensor light comes on together with the engine fault light & whilst on holiday the car gets very lumpy at idle - and cut out once whilst stationery.

Car went back to the indy who plugged it in and it was telling him that I had a whole list of issues - all cylinders misfiring, coil fault, feed problem from DSE, thermostat. He said these couldn't all be correct as the engine probably wouldn't have run with all these faults. Also still some oil in the loom. He has therefore ordered me a loom from a breakers and will fit the the new control unit at the same time as he says that if the unit gets contaminated with oil then the warranty on it will be invalid & doesn't want to risk this. Once these have been fitted hopefully either the running problem will resolve itself or he will be able to diagnose specifically the problem.

Sorry for the long post but anyone else come across this and any idea where the oil may have come from and what issues I may need to prepare myself for