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ABS Issue / Question

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jps635
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Location: NZ

ABS Issue / Question

Post by jps635 » Thu Mar 05, 2020 7:00 am

Have recently developed an ABS issue. Warning light has come on and won't go out after starting (at any time/speed or when stationary).

Have read what I could find on here, referenced the electrical and Bently manuals (no info) and Norm Grills pages.

Given the above info and the fact I replaced all wheel sensors a few years ago (light would come on at a certain speed but then go out after starting), I have discounted a wheel sensor problem.

Have replaced both relays in the ABS pump module.

My understanding is the next step is to replace the ABS ECU. Before sourcing a replacement want to check if there is anything else I should investigate as a likely cause.
'85 635csi JPS (RA2-66)

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NRVOUS6
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Location: North Carolina

Re: ABS Issue / Question

Post by NRVOUS6 » Thu Mar 05, 2020 7:10 pm

I've been told the reluctor ring is a common issue. My light is on, but brakes work perfectly.
85' BMW 635csi, 60k miles, Zinnoberot
01' DINAN 7 S62 Swap Six Speed - Stratus Grau
02' 4.6is DINAN X5 S2 Supercharged
833/3258 produced | 1/27 Dinan X5's
Greenville, NC

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jps635
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Joined: Sat Feb 27, 2010 10:50 pm
Location: NZ

Re: ABS Issue / Question

Post by jps635 » Fri Mar 06, 2020 5:48 am

Thanks, but from what I understand I think this would only cause the light to come on once moving (at a nominal speed).

My brakes also work fine as the ABS circuit is independent of the brake system. Just means, in an emergency situation, the wheels would likely lock.

Unless the light is out i can't get a WOF (aka MOT in UK), but I want to do this by fixing the issue and not just removing the indicator bulb.
'85 635csi JPS (RA2-66)

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jps635
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Joined: Sat Feb 27, 2010 10:50 pm
Location: NZ

Re: ABS Issue / Question

Post by jps635 » Fri Mar 13, 2020 6:47 pm

Got a 2nd hand ABS ECU from Aus, cleaned the contacts and plugged in. ABS light extinguished straight away on starting.

Does anyone know what's inside these and what is likely to have failed?

Can they be repaired (as a spare), or would this be a costly waste of time?
'85 635csi JPS (RA2-66)

emac
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Location: SC

Re: ABS Issue / Question

Post by emac » Sun Mar 15, 2020 1:42 pm

I have seen and used a few online places for various module repairs over the years. Not specifically the e24 ABS, but I think you could find a place that would check it out. Probably something simple like a bad solder joint.

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