ABS controller revisited Topic is solved

[s70dean]

Hey there
I've done quite a bit of reading on this subject but never seen this question asked...My 1999 s70 awd has a constant glowing abs light on start up and once you start moving the speedo and odometer drop out around 25 kmh then the brake warning and tracs lights start to glow and will remain glowing for the remainder of the trip.
It'll do that on every key cycle.
Yes I suspected the controller needed resoldering so i paid a local volvo tech who offers a lifetime warranty on his repairs. I still have the same problem. He says i need to clear the codes before he'll look at it again. I understand his point and ordered a Autel MD802 to read and clear codes. That should be here next week.
My question is,,,,Can I swap in a controller from a different car? Are these units married to the ecm? The reason I ask is I picked up a controller at the local scrappers but it's not a TRACS unit like the original,,,it's an ABS/STC. also different numbers.
Can I just put that in and try it?
Sorry about the rambling just trying to edumacate myself on the subject a little better.
Cheers
Dean

[rspi]

Yes.

[thejrh]

I had the same issue with my 99 V70. Every mechanic I took it to gave me a different story about what needed to happen and one quoted me $800 to rebuild the ABS with no guarantee it would work. Doing some research I found Midwest ABS exchange www.midwest-abs.com. He shipped me a rebuilt ABS (along with the proper torx socket to remove the the old module) for $99 and I replaced the ABS module and have not had an issue since. I did have to pay an additional $50 to him, do to the ABS I pulled from my car having been "repaired" before and he couldn't refurbish it, but for $150 it was well worth alleviating the stress of a constantly malfunctioning ABS module.

[bmdubya1198]

These ABS modules don't need to be coded to your VIN. That's just your ECU and cluster.

[erikv11]

You can swap, but the difference in STC TRACS may be an issue. It is definitely OK to try it, but the replacement MUST come from a 99 or 00 x70. Swap it in, see if it turns off the pesky light. The 98 x70 and the 850 modules are different.

You rebuilder may be right, that is odd behavior, but by far your best source of information is this guy, I would send him email or PM him here on the site (user name Matty Moo): https://www.midwest-abs.com/

[s70dean]

Hey Thanks guys
both front wheels sensors test out at 1.3-1.35 ohms. Speedo is taken from front wheels right???
I should check tone rings tho...
I've been to the Mid west website and there's plenty of valuable info there for sure and it makes me wish i sent my controller there instead of this local guy...I'll play this out and clear and check codes once the new scanner arrives cuz my old Autel just cant access ABS.
The MIL comes on as well with a p1551 code( barometric sensor) ....not sure if this is related to or caused by ABS malfunction?
cheers

[erikv11]

Speedo from the front wheels, yes.

The baro code is not connected to ABS, I haven't heard of them being connected anyway. Often you can clean the connector and that code will go away. Or get one at the junkyard (they are super expensive new).

[Matty Moo]

A 99-2000 stc unit will work fine. That baro code isn't connected to the abs at all. The volvo guy should have pulled the abs codes.

[s70dean]

Thanks again
I compared the numbers on the scrapper unit from MidWest's info page and it was indeed pulled from a 1999 stc equipped s70 but unfortunately I'll have to wait to pull/clear codes til the new scanner arrives.
I'll head out to the scrappers and grab a different baro sensor.

[s70dean]

Hmmm..So I Successfully picked up a couple different Barometric sensors to swap in and both produced the same results as the original..
So where do I start looking Now? The code it's producing is p1551 = Baro sensor short to B+
Hard to find any info on this... seems most people just change the sensor and they're good to go.