This is a follow up to my recent problems, I did have the "Brake Failure" message, now I also have "Transmission Needs Service", "Engine Needs Service", etc. Also, on some occasions I cannot start the vehicle, it turns over but will not start. I have all kinds of icons illuminated: (!) (ABS), etc. Major electrical problems I believe. At times as I said I cannot even start, I try to start, I hear a clicking noise from the shifter, and it turns over but will not start. HELP!

Sounds like you need a new battery, start with putting a new battery in the car and then see what if any of your messages return.
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Rich K. http://www.volvospeed.com/bay13.htm bay13@cox.net

Actually, I did that already, I put a new battery in a few weeks ago, but the problem are still there after the new battery was installed.
Thank you for the suggestion.

Any chance the battery is poorly grounded (it's back in the trunk
on an S80, right?). Poor ground can cause multiple weird
electrical problems.

Yes the battery is in the back of the trunk, I will double check the grounding, thanks.

Your next step would be to take the car to a shop that has a VADIS cart so they can read "ALL" the codes stored in the various modules on the car, they may be able to find one problem that might be common to all the messages, like your ABS module not giving correct speed to the trans module or the engine module, just a guess, but usually something common can be found when lots of things look like there is a problem.
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Rich K. http://www.volvospeed.com/bay13.htm bay13@cox.net

Had a very simular problem with my 99 S80. It ended up being the ABS Control Module. Had it replaced and not a problem since.
Bob

Thank you, ABS Module is suspect.

http://home.earthlink.net/~vicrocha/Volvo_Parts/Volvo_V70_ABS.htm

Vic Rocha is the man you need to talk to if you ABS module is faulty.