Do it yourself ABS module repair. Topic is solved

[czechm8]

Thanks Ozark Lee for the great write-up.
I was looking for this info last week, but did not find it . I found some less detailed info in other Volvo forum in the UK.
To tell this story right I have to start with my trouble codes and MILs. I bought a 99 S80 2.9 with 200,000 miles on it a few weeks ago knowing that it will need some troubleshooting.
Armed with a basic code reader I got the following codes:
P0722 Output Speed Sensor Circ No Signal
P1618.. Volvo specific code ECM-530D I think a Transmission code
P1550..Volvo specific code ECM-510F Vehicle speed sensor
These would not reset. Check Engine was solid on all the time. Intermittently I would get ABS light, Traction Control light(triangle car skid) and on some rare occasion the message BRAKE FAILURE STOP SAFELY ASAP.
From this and other Volvo forums I came to suspect the ABS controller is acting up. To prove my hypothesis I decided to do the repair myself.
I was a little bit of risk, but as long as I could cleanly open, close and seal the unit back up, the risk would be minimal.
The fuses on my car that I had to pull were 11 and 12(the ones labeled ABS). Removed air box and 4 bolts and the ABS module with a 5/32" socket very gently.
Once on the bench I took my time opening the unit. First I removed the 4 retaining rings. Then I went under the lip with a thin flat screwdriver to break some of the adhesive/sealant (like Ozark Lee). Then I took four 3 inch screws and attached the ABS module to a piece of plywood through the mounting holes.
Then with a pry bar and appropriate height fulcrum I lifted a side until I heard the sealant shear(see pic).

Then I went around the perimeter till all sides broke loose. The key here is to make the whole lid come straight up evenly.
Once opened, I hit all the major through-hole solder connection points(see pic) with a small tip soldering iron.

volvoabsrepair805kr2.jpg (136.18 KiB) Viewed 7540 times

Some people describe a soft conformal coating on their circuit boards, but mine did not have it. The coating would have to removed around the solder points for a proper repair.
I then put the cover back on without resealing it to see if the repair worked.
First start, check engine and ABS lights are on. As soon as I hit 20 mph ABS went through a self-test and ABS light went off. Two more drives later to work and lunch(approx. 20 miles) the Check Engine light went off.
3 days later and still not even a peep, so if I was a betting man I'd say the ABS module had some dry/sold/cracked solder joints.
So this morning I took the module back out and sealed it by putting down a thin bead of silicone sealant in the groove and hand pressing the cover on.
Then I cleaned the excess, put the retaining rings back on, and let it dry for an hour with some weight on top on it. The result is in the last pic.

So thanks all the contributors for giving me the confidence and knowledge to do the repair.
I apologize for the quality of some of the pics from my "garage" camera.

volvoabscontrollerzd8.jpg (41.3 KiB) Viewed 7540 times

[MadeInJapan]

Good job! It's always nice to hear these success stories.
I'll add a link to the S80 section to this.
Regards,
MIJ

[turbotim2]

Alright, I will now follow in line and attempt the repair myself! I have been putting this off for too long.

[et3surge]

I had all these issues but I found someone here that rebuilt the units, last year. I ordered one and sent him mine. He had good results with several people on here as well. I wish I knew what his name was to re-post but if you guys keep having these issues it was a cheap good solution that is still running with no problem.

Found it here is the post with links to Victor Rochas rebuilt ABS modules. I am a believer...
https://www.matthewsvolvosite.com/chat/p ... hp?p=17308
SH

[MadeInJapan]

Thanks for the post, but Victor's been on our recommended vendors list for a few years now: https://www.matthewsvolvosite.com/volvo_parts.php
There are also 2 other repairers for these modules that are reputable that I know of.

[kranz]

I have a '98 V70 with about 140K miles. This spring the ABS light started coming on frequently. Within weeks, it began to stay on always. After finding this thread, I figured it likely that my ABS suffered from the same common solder malady described in this forum.

So, this weekend I tackled the problem. After removing the unit and opening it up (I found the suggestion of screwing the unit onto a piece of plywood to open the unit with a pry bar particularly helpful) I inspected the solder pins with a magnifying glass. Everything looked good except the two power pins that clearly had cold solder joints. So, I decided to just re-solder the power pins and let the other sleeping dogs lie. Since other folks commented on the difficulty in heating these pins, I used a hotter 100 watt solder gun. Even so, I had to apply heat for a fair amount of time before the solder would flow nicely. No ill effects to the circuit board.

Once the unit was reinstalled, I fired up the car and the ABS light went out immediately at idle, without even moving the car. After a test drive, everything appears to be normal.

Many thanks to those in this forum who took the time to document the fix for this ABS problem.

[turbotim2]

I just took the module out and separated the halves. Its really hard to tell if there are any breaks in the solder. On the power pins, I don't really even see any solder tracks, how much solder are you supposed to add? Or will getting it to flow be good enough to reestablish the connections?

[turbotim2]

Couple of other notes:

I ended up stripping one of the heads of those tiny bolts that hold the module on as they were rusty. I had to use a dremel and grind off the head which turned out to be not as bad as it sounds.

While trying to separate the halves I realized that there are some star nuts on the ends of the bolt sleeves that needed to be removed before the halves would come apart.

[turbotim2]

Well I finished the job and I think with success. I was not confident I had fixed the problem as I couldn't see any broken connections. I went through each of the pins as said and added just a bit of solder after getting them loose. Put it back in, the lights went out during the test drive so I am hoping I got it! Thanks for the help on here, this was not a difficult job at all even having to grind one of the bolt heads off to remove the module. I didn't have any trouble accessing the bolt heads either, not sure what other people were running into there.

[Xenolah]

Hello, came to this site seeking a solution to the ABS problem - I followed your advise, opening the module and re-soldering the circled areas. The light remained on shortly, but turned off once the car started moving. Thank you very much, these modules are not cheap in Australia.