ABS Module repair

[PAULF]

I have got the dreaded ABS red flashing exclamation and yellow ABS light on. They come and go intermittently and a VCDS scan gives the intermittent communication error. This all points to the module going TU, so I tried to get another one.

Without saying anything about the classified section, I wasn't able to get a compatible pump/module so I decided to get it repaired.(there was one on e-bay, but it had been sold before I could get it myself)

Having taken the module off, I thought it might be an idea to have a go myself. I found a guide here http://www.lbak.dk/Audi/Repair_ABS_unit_passat.pdf, and have opened my unit up and found one of the larger wires loose. I'm just off to get some better soldering equipment, and I'll try and repair it. I'll post the results later.......

 

[brasiliangringo]

Get some soldering flux to make the solder go where you want it to after giving the contact points a good clean with an electric type contact cleaner.

Failing DIY, Im sure i can source you one through my contacts if the repair doesnt work.

 

[PAULF]

Thanks, you've hit the nail on the head!

It looks like I'm going to need to get some more flux, and some better solder. I've removed the damaged links successfully, but I'm not happy with the replacements. The solder is not taking to the pads properly.

I used a pin and jewellers flat bladed screwdriver to remove the gel from the area of the repair only. The gold wires are remarkably thin, so I have avoided them like the plague!

If I don't manage, I'll give you a shout about a replacement unit

Paul

 

[PAULF]

Hmm,

Failed - internal memory error. I would expect this was caused by me exerting excessive heat during the repair, so I now have a properly ******** unit.

I have worked SMD stuff before, and this was did not look particularly hard. However, you DO need reasonable quality tools, and solder. The solder I had was fluxless, and Maplins only sell unleaded - which is useless. I tried using a flux pen, that was all they sold, but it was not great. Anybody who has done circuit repairs before shouldn't have too much trouble, if they have the right gear. The 'how to' was spot on, even down to the same two links having worked loose.

 

[PAULF]

Another update!

I had a look this morning, and found that I had moved a couple of links that shorted to ground. This was done when I hooked the module up for test before reassembling it. I moved the links off ground, and tried again.

Still got three beeps, so put the pump back without the module and went to bleed the brakes. Three beeps and a red exclamation is also low fluid - I had lost some during the pump removal and refit.

I tried the module again, and now just had the amber ABS light and a couple of fault codes, that I cleared. No red exclamation or beeping.

I then found you can remove/refit the module without removing the washer bottle or pump. (On a 2.5TDi)

Move the power steering fluid reservoir out of the way, and remove the two top bolts on the ABS pump bracket. Slacken (or remove) the lower bolt. Remove the three screws holding the coolant reservoir and move it out of the way. Using a T20 bit in a 1/4" drive ratchet, with various combinations of extensions and wobbly drive/UJ adaptors, slacken all 6 Torx screws holding the module on. There is enough 'give' in the pipes to be able to move the bracket a couple of inches inboard, to get the module in and out.

Beware of the small connector at the bottom of the module - I removed this last by turning the module to access the clip.

Having reassembled everything, I cleared all the fault codes, and took it for a run to get rid of the amber ABS light. (If the amber light is on, the car may need to move to get signals from the wheel speed sensors and put out the light)

Unfortunately, I have a re-occurring front left speed sensor fault. I suspect this is a fault inside the module caused by me, and now it is glued up,I'm not taking it apart again! A bit of a shame but the experience was useful, and at least it's only a small amber light on until it's fixed, as opposed to the big red exclamation which blocks out other DIS info

I'll now go back to trying to find another unit - if anybody has a 8E0 614 111 A or E please let me know.

 

[jcb]

that looks waaaay too fine for my fat fingers to attempt.
good effort having a go.

BBS Reman may still take it in as an exchange for a fee

 

[SonicDeathMonkey3]

I've used BBS Reman and was very happy with their service. I also used Automotive ECU Testing - ECU Repair and Exchange for a Volvo V50 pump. They were well cheap and the unit is fine.

 

[PAULF]

Thanks, I've used ECU Testing for my dash quite happily - but having opened and ******** my unit, I suspect the repairers wont want to know.

I'll check on Wednesday and see what they all say.

 

[bmarshall]

Ive done lots of repairs on bosch abs units. You need to scratch/roughen up the surface with a dremel before soldering and get plenty of heat on the pad. Be careful of the other thiner wires next to it. You wont do any damage to the eeprom with the heat.

 

[PAULF]

Thanks mate,

The problem is I tried to do it without all the tools I needed - flux-less, thick solder, my iron was only 40W and a little to big and no decent flux. I am in the middle of swapping hers with mine at the moment, so I will hook up her module to my car to see what is damaged or not. I may be able to rescue it, but I suspect I may have either moved the thin wires or shorted/moved something else - maybe the links at the other end of the board. I'll see in a bit.........

I used to design and repair SMD stuff so felt confident even with duff gear, but it has been at least 10 years since and you lose the 'touch'.
As I said earlier, the job isn't hard, but you do need to have a good, thin iron, flux, thin solder( 24 gauge max) something to rough up the pad, a magnifier (maybe) and flux cleaner.