Was the abs module ever corrected

[atilla_the_fun]

I believe you can, but only if you sent in the electronic half and not the entire part, including the half with the hydraulic valves (brake fluid).

[vt_maverick]

Generally it's the electronic half that fails though right?

[JAMAS]

I have 2 modules (well 3, but for the purposes of this discussion I'll say 2).....

I purchased 1 from a junkyard to replace the one that went bad. Now that my problem is solved (hopefully not temporary), I was hoping to send the broken one off to be repaired.

then repeat the cycle each time the abs module fails.

[atilla_the_fun]

JAMAS, are you any good at soldering? I've found some info on BOSCH ABS modules malfunctioning in AUDI and VW (BOSCH 5.3).

http://www.youtube.com/watch?v=UqtowdSDbxU

http://forums.qrz.com/showthread.php...sch-5-3-Module

I'm not sure how closely our module's electronics match the 5.3 unit (produced in the late 1990's, but there is a good chance that our issues are as simple as the silver wire breaking as seen in the german cars listed above. If you would like to try to open your spare up, you may be surprised at what may have been the issue all along.

Joseph

I may open mine up this spring. I find that the cold allows it to function sporadically.

[rsteinmetz70112]

Sporadic functioning is a sign of a loose/broken connection.

I think I recall someone stating that the VX units are somehow sealed (encased/coated) to prevent water damage and therefore more complex to repair.

I did a lot of research online on these things and don't remember where I found that information.

I also recall Trooper (and some other) units are very similar, but may have different programming. Never could determine for sure if they were the same or if they could be reprogrammed.

[atilla_the_fun]

Sporadic functioning is a sign of a loose/broken connection.

I think I recall someone stating that the VX units are somehow sealed (encased/coated) to prevent water damage and therefore more complex to repair.

I have also read this many times on this board, but I had the feeling that all ABS units are sealed. In the AUDI/VW's case, they require careful prying open of the the case, and slicing through the sealant/glue that holds it together. I won't know until I do it, though.

The sporadic activation did feel to me as an obvious loose connection, as computer-boards don't suddenly work at lower temperatures if they have an internal de-lamination or they need to be re-balled.

A blown capacitor reduces capacitance to 4% of the original value, and this value would be even lower at low temperature, according to this page on ceramic caps (http://www.niccomp.com/Products/TC_Ceramics.pdf).

[JAMAS]

eh, I'm alright with it.

Time is the real issue though.


It sure would be nice if it was something easy.

[LittleBeast]

I still am not sure why everyone wants to fix this when the ABS on the VX for whatever reason actually increases braking distance.

[tom4bren]

I still am not sure why everyone wants to fix this when the ABS on the VX for whatever reason actually increases braking distance.

X2

I'll be towing that ^&%&*% trailer home tonight with the VX. Hope I have better luck w/o ABS than I did wit.

[SlowPro48]

I still am not sure why everyone wants to fix this when the ABS on the VX for whatever reason actually increases braking distance.

Pull a 4000 lb trailer on a winding mountain road after a hard rain and you'll understand!

Actually your argument could be said of the ABS on just about any vehicle. If you're a skilled driver who can constantly brake at the point of incipient slide and you're on clean pavement, you can best the results of most ABS systems. In the real world, however, people are getting old, driving skills aren't what they used to be, feet are numb from pinched nerves, diabetes, etc. and there's gravel washed across the road - usually in the middle of a turn. ABS can make the difference between jack-knifing into oncoming traffic or going around the turn.

Joseph, that repair video shows a Bosch 5.3 which is a four channel module. We've got the Bosch 5.4 which, unfortunately, is a three channel model. (How about that logical German nomenclature, eh?) Some Troopers use the 5.3 but some have a 4 channel. The 5.4 is also found in the Dodge Durango & Dakota, mid 00's Ford F-150, late 90's SAABs and a bunch of other not-so-sporty cars. (Wait... is a Buick Lacrosse sporty?) I don't think you're supposed to use a 5.4 module from another vehicle though. Supposedly they're vehicle specific - programmed according to vehicle mass, dynamics, braking system, etc.

If you try the repair yourself and it turns out it's your "silver" bus wires, good luck soldering those and having the joint last! I know you probably meant silver in color but in case you meant silver metal... well... unfortunately that's not the case. Those bus wires are actually aluminum. No idea why they would use a wire made of material known to work harden, fatigue and crack in an environment subject to heat cycling and vibration but that's what they did and apparently that's the most common failure point in these units. Go figure...

When my ABS started flashing a Code 43, I thought briefly about Dremeling it open and repairing it myself but then I found out that might involve soldering aluminum and bailed on the idea real quick. Decided rather than risk ruining the unit with my jiggly 35W chisel and cataract addled eyes I'd to leave it to a pro who's got the proper flux, a skinny tip - and plenty of practice on other people's units! The hair-fine gold wires on the circuit board are allegedly another common failure point. No special flux needed for that - just plain old rosin core, good eyes and a steady hand.

On my unit, the power busses were good but a pad for a wire serving the FR solenoid had pulled completely loose from the board. The eBay ABS repair guy in Charlottesville, VA (Matt) fixed it and I would highly recommend him - good communication and blazing fast service. I think he normally charges $99 if you purchase service through his website (cheapabs.com) but check eBay and he's usually running an $85 auction for the same service. The title will say Bosch 5.3 for an Audi A4 or A6 if I recall - but he'll do a Bosch 5.4 for the same price. And that includes shipping the unit back to you. Can't beat it. Five minutes to take the unit off, ten to box it, slap a label and some stamps on it and put it in the mailbox and five minutes to re-install the unit. Quickest, easiest fix ever...

And yeah - you send just the electronic control module not the pump/hydraulics. You can drive the vehicle without the module but expect a little more tire scrubbing/chirping in parking lots and other slow speed/tight turn situations. Oh and you won't have ABS.

BTW, there's no harm in it but you really don't have to force the ABS to function every once in a while to "keep it all loose" because the solenoids and the pump get cycled during a system test every time you start and drive the vehicle.

[VX KAT]

Awesome explanation and info SlowPro!

[xcelr8]

sorry to open a months-old thread, but has anyone tried the soldering? I now have light on intermittently. Here's a question: I want to keep the thing on the road.If I separate the module from the rest, will brake fluid spew? I want to try the soldering but not if I am going to be bleeding brakes at night.

thanks, all!

[VX KAT]

sorry to open a months-old thread, but has anyone tried the soldering? I now have light on intermittently. Here's a question: I want to keep the thing on the road.If I separate the module from the rest, will brake fluid spew? I want to try the soldering but not if I am going to be bleeding brakes at night.

thanks, all!

No, nothing will spew out at you. Here's what it looks like with module separated:

[xcelr8]

As always, thank you Kat! I can't believe at 65,000 miles this thing is broken. Bosch usually makes stuff pretty good...I'm pretty surprised. I know it's 13 years old, but nonethelsess...should still be good.

[VX KAT]

Have you seen the guy on ebay that repairs the ABS modules for $99?
Here's a few posts on it.

http://www.vehicross.info/forums/sho...s+ebay+rebuild

VT_Maverick had his done back in May by this guy and it apparently works as new. A new ABS unit is like $2,000 - $3,000