My ABS light is on and off intermittently. Sometimes it comes on while driving, but mostly it shows up when the car is first started. Then it may go away after engine off/on cycle. Or it may not. The car is a basic '98 S70 5-speed with no traction control. The ABS module was replaced under warranty in 2004. How do I determine if the problem is the module or sensors or something else? I already emailed Vic, the ABS repair guy about it and may send the unit in for him to test. Is there anything I can do in the meantime?

TIA!

--
Vladimir. '98 S70 base, 5-speed manual - his, '93 945 (approaching 250K miles and rolling on...) - hers

Removed the ABS unit and sent it to Vic for repair. This was actually a while ago. I just never got around to writing it up. Also, I wanted to have some miles on the repaired module so as not to have a false positive. Well, Vic's service was outstanding as far as speed and communication. I emailed him, he replied with instructions on how to remove the unit (oddball E5 torx socket is required to undo the bolts holding the unit) and mail it in. From the time I sent the unit in to him until I had the unit back to me and in the car operating was exactly one week. I live on east coast and the unit was shipped to California, so it is one of the longest shipping delays possible. Still, in one week my car was back in ABS land. I drove the car without the module, which was fine. No speedometer and no cruise control (no ABS, of course), but otherwise normal driving. Once the unit was back in the car the ABS light went out by itself. It may be because /I reset the CEL once during the time the module was out. Anyway, after over a month of driving no ABS light and I did test ABS operation both on purpose (on some wet leaves) and just as a matter of normal New England driving. Everything seems to work just fine. As most people who have dealt with Vic and his ABS module repair, I highly recommend it. It is much cheaper than the new module and supposedly more robust.


--
Vladimir. '98 S70 base, 5-speed manual - his, '93 945 (approaching 250K miles and rolling on...) - hers

Sounds like the the plug wires are coming loose from the module. Vic will fix that. If the lights are on, get the codes read. Even generic code readers will pick up a couple of ABS codes.

Klaus
--
Did you do your Random Act of Kindness today?

don't know if the same for 96 850, but i just fixed mine. I pull the abs ECU unit out and opened the box. resoldered the points on plug side. Also, the insultation was flaking off the two wires from pump to abs ecu....jesus, volvo still using crapy insulation.
I rewrapped them with rubber hose and zip ties.

ABS light is now out and all is good.

Be very careful prying the box open with shape tool. you can cut yourself. use sealant to box up again. there are 4 little star retainers around the screw bushings.. just gently pry under them but don't let them fling across the room. you can reinstal them with right size 1/4" drive socket to use as tap.

Rob