Hi everybody
I work at a volvo specialty shop and we have a car we are completely stumped by. Its a 97 850 non turbo w/ tracs.
Came in for abs/tracs lights on the dash. We checked the wheelspeed sensor with a voltmeter and they seemed ok so we popped in a control module. (He also had one put in at the dealer a few months earlier which didn't help him.)
We thought he might have gotten a faulty one from the dealer.
Lights were still on. We scanned it while driving and the Left rear wheel speed sensor was losing signal occasionally while going over bumps with the brake pedal down causing the abs to go crazy. The L and R come as a kit
so we replaced both rear wheelspeed sensors.
Problem is still there. Pump is not leaking either and all four pin wheels are ok. Don't see any bent or broken pins on any of the connector either.

Has anyone seen this before?
there are no other symptoms either.
hoping for some help
thanks in advance