1999 Volvo V70. Will not pass N.C. state inspection!Engine light is on. Test say it is speed sensor, however other lights (ABS,traction light,service,etc…)come on occasionally (back hatch open light stays on). If traction light comes on, the car feels like it is trying to start off in 3rd gear. Many times the speedometer shows nothing (0 mph). At times when the ABS light is on, the brakes grind when applied or the wheels make a gringing sound in a sharpe turn. A once was Service Mngr at a Volvo dealer said is was only a $100 module that was needed to fix these errors. Volvo wants to replace the ABS system($$$$) and everything individually. I’m at the point of removing the tags and leaving it for junk on the side of the road!!
First, have an auto-electrical shop test your alternator for a bad or weak diode. This will put A/C ripple into your electrical system and cause the sort of problems you describe…If the alternator checks out, then your Plan #2 sounds good…