I have the same problem with my 2000 v70 glt a not only does the break, abs, and check engine lights come on and the speedometer and odometer don't work but the arrow starts flashing and the vehicle seems to start in high gear! Which of the many speed sensors should i check?

The most common problem is with the ABS control unit. You will most likely have to replace it. It is located under the brake hydraulic unit (not the master cylinder). This part can be purchaced from a Volvo dealer, or sent to one of the many places that repair them. If you choose to fix it yourself, and would like the name of one of the companys that repair them, let me know.

Have it Scanned and see if the Vehicle Speed Sensor is bad.

If you have a speedo and ABS issue together it needs an ABS module. Module receives the speedo signal and sends it to the speedo and the transmission module. The transmission module needs the signal to know when to shift the trans. It is going in to limp mode hence the lack of power. Replace the ABS module

01 v70xc abs mod changed twice same problem stays no trip od ,no od trac control light on nocruise.