FYI....I took out the ABS Module, took some Electrical contact cleaner and cleaned the contacts and put back together. No more lights.....it's been 4 days. I'm keeping my fingers crossed.

Thanks for your help....that'll be my project for the evening. I'm putting the car up for sale, but need to get that fixed first. Thanks again!

gr78core is right, the ABS/STC units on the S80 have a limited life span and all of them will eventually fail as the late 850 and 70 series have failed.
The correct socket to remove the unit is an E5 Torx socket.
Some people have used a 4mm or a 5/32" socket, but once in a while a bolt is damaged in the process.
Here's more information on this issue.
Vitor's Volvo ABS information
Click on the ABS / TRACS Repair link.

My info shows 2000 model:

to Chassis 116810 9492900-7
From Chassis 116811 8619469-3

It would be safest to remove the Module or use a mirror and read off the bottom of the unit. You can access the module by removing the Air Cleaner assembly, then remove the bolt at the base of the Fuse box behind the Air cleaner and lift out of the way a little. You can remove the ABS module with a socket (5mm) I believe. Remove the cables from the module. Always disconnect the battery in the trunk first. I'm not a mechanic but I replaced mine with a used one. Check the mileage on the module before you buy, they have a short (half-life).

Gary