ABS module (Bosch 5.7) going for a rebuild/repair

[BimmerJB]

Hi Everyone!

I have a 2001 BMW X5 3.0L. Just got it in August and I got the xmas tree lights with the ABS, Brake, and DSC lights. I'm sending it in for a rebuild through cheap-abs.com. Anyone ever use them? People recommend cheap-abs, EAC, and modulemaster.com. Let's see how this works out.

[HEISING]

I have never dealt with these guys so I can't comment......I just rebuilt my own and it works great now. Not a job for the back yard mechanic though. Lots of surface mount parts to blame.

[diyanich]

Originally Posted by BimmerJB

Hi Everyone!

I have a 2001 BMW X5 3.0L. Just got it in August and I got the xmas tree lights with the ABS, Brake, and DSC lights. I'm sending it in for a rebuild through cheap-abs.com. Anyone ever use them? People recommend cheap-abs, EAC, and modulemaster.com. Let's see how this works out.

How did you determinate that the module is bad?
Any codes? in my case it was a bad abs sensor,$50 bucks and a lot of swearing solved the Xmas lights.

[HEISING]

I determined that the module was faulty through a series of steps. When I start the vehicle and drive it for about 10 mins, the yellow lights appear. This is the indication of a possible thermal issue. The next morning when the X5 was cold, I removed the drivers side head light which allows clear access to the module. I Got out the hair dryer and heated the module slightly (truck not started but key one position before spring loaded starter position) and sure enough the lights came on. Turning the ignition switch off and removing the key now, back to the front of the X5. Now with a can of Super Cold Spray, I cooled the module and re insert the key into the ignition, turn it one step before the starter position again, and now no yellow lights. This has now determined that the problem is the module and it is a thermal issue. So out came the module and on my test bench it went. There were quite a few problems in my module. Failing surface mount capacitors and intermittant connections. I imagine this is due to thermal cycling. This is not a job for anyone without surface mount re-work equipment and very steady hands. There is gold bonding wires in this box finer than a hair, under a silicone flexible jelly. If this jelly is disturbed in the wrong area just once, the whole unit is not repairable, as these bonding wires attach directly to the semiconductor and processor dyes. The whole internal circuit is on a porcelain substrate which makes soldering difficult because the substrate sinks the heat away from the equipment. There are also 2 diodes and an electrolytic capacitor behind the 2 heat sinks on the solenoid side (Bottom of the unit) There is no access to these parts unless the spot welded tabs are removed. There are 2 semiconductors attached to each heatsink. These semiconductors are also welded to internal tabs (No soldering in this part)

[diyanich]

Originally Posted by HEISING

I determined that the module was faulty through a series of steps. When I start the vehicle and drive it for about 10 mins, the yellow lights appear. This is the indication of a possible thermal issue. The next morning when the X5 was cold, I removed the drivers side head light which allows clear access to the module. I Got out the hair dryer and heated the module slightly (truck not started but key one position before spring loaded starter position) and sure enough the lights came on. Turning the ignition switch off and removing the key now, back to the front of the X5. Now with a can of Super Cold Spray, I cooled the module and re insert the key into the ignition, turn it one step before the starter position again, and now no yellow lights. This has now determined that the problem is the module and it is a thermal issue. So out came the module and on my test bench it went. There were quite a few problems in my module. Failing surface mount capacitors and intermittant connections. I imagine this is due to thermal cycling. This is not a job for anyone without surface mount re-work equipment and very steady hands. There is gold bonding wires in this box finer than a hair, under a silicone flexible jelly. If this jelly is disturbed in the wrong area just once, the whole unit is not repairable, as these bonding wires attach directly to the semiconductor and processor dyes. The whole internal circuit is on a porcelain substrate which makes soldering difficult because the substrate sinks the heat away from the equipment. There are also 2 diodes and an electrolytic capacitor behind the 2 heat sinks on the solenoid side (Bottom of the unit) There is no access to these parts unless the spot welded tabs are removed. There are 2 semiconductors attached to each heatsink. These semiconductors are also welded to internal tabs (No soldering in this part)

Well,I see...

[chefwong]

I just had mine replaced...but this was with OEM unit at $900'ish bucks ?
My indy who I trust does not like any of the rebuilt modules.

I have yet to confirm, but I do recall *like* units Bosch branded for around $550....

[koister2001]

I got mine (another one for my old E39) rebuilt by Module Master
ModuleMaster rebuilds ABS modules for as low as $100, 2 day average turn-around, 5 Year Guarantee

The only trouble is that you have to remove your faulty ABS unit (may require headlight removal).

[BimmerJB]

Originally Posted by diyanich

How did you determinate that the module is bad?
Any codes? in my case it was a bad abs sensor,$50 bucks and a lot of swearing solved the Xmas lights.

I took it to my indy and they ran test on all the sensors, and determined it was the module.

[BimmerJB]

Thank you everyone for your replies!!

I just got email back from cheap-abs.com. Seems like my unit is unrepairable; connections are all good, just maybe the main circuitry is kaput!!! I may need to just buy another unit. Any suggestions on where to purchase??

[mrbmwx5]

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