528 E39 ASC and ABS warning lights

[kevinpsw]

The two lights came on simultaneously while driving at speed through heavy rain. They stayed on for the next 50 miles. After a brief stop they went off for a couple of minutes before coming on again. They stayed on for the remaining 2 hours of the journey. No fault with speedo, I didn't check the cruise control.

Diagnosis? ABS sensor? Expensive?

[Neil.D]

The ABS/ASC sensors (basically the same thing) take quite a dislike to water. Deep puddles tend to kill them. Owing to the heavy rain I would say they were just having an eppi moment. If the light has gone out then I wouldn't worry. Just to make sure I would test the ABS/ASC whilst at low speeds by putting the brakes on hard and then trying to spin the rear wheels.

Neil

[kevinpsw]

The BMW specialist repairer has diagnosed the fault as the ABS control unit. They want £740, mostly for the unit itself. How easy is it to remove and get this unit reconditioned? Anybody know of instructions for fitting on the internet?

[B19GRR]

Have a read over here:
http://www.bmwland.co.uk/talker/viewtopic.php?t=73...
http://www.bmwland.co.uk/talker/viewtopic.php?t=68...
Also do a search there on abs AND asc, there are loads of posts as it's quite common - I have it intermittently, keep meaning to take it to the indy to get the codes read.

This place rebuilds the control module for £100 apparently.
http://www.bba-reman.com/catalogue/DetailedProduct...

Cheers,
Rob

Edited by B19GRR on Wednesday 4th June 21:47

[kevinpsw]

Codes read as:

67 Intermittant Interference

66 Power supply wheel speed sensors

7 wheel speed signal front left (presumably left as you sit in the car looking forward)

Dealer said likely to be £740 for new ECU and code to vehicle but could be N/S/F ABS Sensor £167.

Is it worth changing wheel sensor first? Is this easy?

Regarding fitting a recon ECU. Dealer suggested that coding to vehicle needs specialist equipment and they refuse to fit anything other than a new unit. Is changing the unit easy?

[[TW]Fox]

It's almost certainly the speed sensor NOT the ASC control unit!

[Mroad]

I don't know the particular model but given the fault codes I think the first thing I would do is check the front LH wheel sensor connections are not corroded or damp giving a short circuit/poor connection and intermittent fault (especially when driving through water). Start with stuff that doesn't cost an arm and leg to do, you never know. I would be surprised the garage haven't checked this BUT I don't trust any garage anymore.
The connector on the upper end of part number 10 below:
http://www.realoem.com/bmw/showparts.do?model=DD52...

Edited by Mroad on Friday 6th June 12:45

[mr.man]

When my wheel sensor failed I had the same lights lit up. Also the auto gear box played up by being
reluctant to change up out of third gear. Think about £90 fixed the fault.

[kevinpsw]

Thanks. I've ordered a new front sensor and I'll start with that.

[miniman]

B19GRR said:

This place rebuilds the control module for £100 apparently.
http://www.bba-reman.com/catalogue/DetailedProduct...

They do indeed and a good job they do too! They did the ABS ECU on my A4 - 4 day turnaround IIRC, cost £100. Quote from dealer = £950. It has to be worth a try even if it doesn't work!

[kevinpsw]

The lights went out for a day but came on again this afternoon. It makes me think it's the wheel sensor. So, I'll try changing that then go for the recon ABS ECU.

[cozzy71]

Kevin,

Just had the same happen to me. We changed the front left wheel sensor, but the fault kept occurring. It turned out it was the ABS module which is around £740 for a new one however there is a firm that advertises on ebay called ecu-testing which will recondition your old one. They charge £150 plus vat and postage or if you are trade £100 plus vat. This also has a two year guarantee. The turn around was really quick as i sent it on a Thursday afternoon and got it back Tuesday morning. It works fine now,
Cheers
Chris

Edited by cozzy71 on Monday 9th June 08:44

[kevinpsw]

Exactly my plan. Change the sensor then, if this doesn't do the job, send the ECU off for repair. Did you remove and refit the ECU module yourself? If so, was it easy?

[miniman]

On my A4, it was hard because you have to take off the wheel, wheelarch liner, washer bottle, then the ECU. On the E39 it looks to me like it's just 6 very easily accessible torx bolts. BBA Reman site has instructions with photos on their site. Even with the A4 complexity it was 60 minutes total including reassembling it after removal.

[pezz]

This has just happened to me too on my 99 528i

The fault showed itself as left wheel sensor gone open circuit..
This sensor was been changed and the problem, initially intermittment, is now much more frequent.

Again with my situation the car was sat in traffic in a heavy downpour a couple of weeks ago. The problem has knocked out my speedo, the MPG meter plus seeing the two warning lights.

So maybe the sensor going screws up the module? or maybe the rain gets into abs module??

I am hunting around for solution and found ECU testing in Derbyshire http://ecutesting.com/bmw_common_ecu_failures.html

Cozzy did you remove the unit and continue to drive the car until your unit came back?

Cheers

Derek

[miniman]

pezz said:

Cozzy did you remove the unit and continue to drive the car until your unit came back?

I drove my Audi with the ECU removed. There's no phsyical break into the hydraulic system so you have perfectly normal brakes, just no ABS. However I did worry a little that if I had an accident an insurance assessor might look at it and refuse to pay out on the basis that it was not "roadworthy" in that condition.

[pezz]

Excellent.

Thanks for that.. I will try whip out the module send it off for refurb.

Still puzzling how so many of these modules start to malfunction are being driven or when the cars standing in a downpour...