Volvo Repair: 98 V70 (120K) ABS Braking system, wheel speed, abs system

Question
The dashboard indicator light is warning of a fault in the ABS
system. Is this dangerous and what usually goes wrong with this
system?

Answer
Well, 99 percent of the time the ABS module fails.  It registers a fault in the pump motor circuit or wheel speed sensor logic and then disables ABS.  The problem is there is no fault in either circuit.  The ABS starts detecting phantom symptoms.  The only other fault I've seen recently is an actual wheel speed sensor fault.  It is alot less comman but has happened.  The module is between 650-800 dollars.  I would get a hands-on diagnosis before spending that kind of money though.  You can replace the module yourself very easily so I can guide you through the process if thats what it is.  Take it to the dealer so they can get the trouble codes from the module with their computer and verify my thinking.  Its not dangerous in the fact that the brakes stop working.  All the mechanical braking systems will work just fine, the ABS and/or traction control may not function though.  Safe to drive but not recommended.

James