Volvo Repair: Possessed Volvo, garage door opener, network wires

Question
James, here are the indications I have on my 2000 s80 t-6. The ASA Volvo tech reset everything and it was fine while it was at the mech. But as you can see below, funny stuff is happening.

Does this sound like the ECM has gone wacky? It looks like none of this stuff is ready bad because it comes and goes and I have had everything checked. IE: I get the power steering fail, yet it has plenty of fluid, works, doesn't leak and makes no noises.

Help.
5/2
Picked up car, abs light on, messages , brake -stc-abs-power steering fail.
At about 3 miles,  Check engine light came on. Cruise control, inop.

5/3
Dove car to work, only lights on check engine, Cruise control working.
At lunch, no lights at all, everything working.

Drive home, abs, brake messages on, cruise inop again. Get home, program garage door opener, just for the heck of it, disconnected batter ( cables were loose) to see if would reset engine light. Start car no lights, but realized that visor lights, garage door opener  and sunroof inop, disconnected battery again, idiot lights and messages all back, but still no sunroof. Check fuses, all were ok, went back to battery, just disconnected the small lead, looked through the back window at visor light, as I touched the lead, lights came on then immediately went out. Took fuses out, reconnected small lead, put fuses in, lights and sunroof started working again.

5/4 back to usual, abs, brake, sts, power steering, engine lights all on, cruise control inop, but lights and sunroof work ok.


Answer
Well what sounds like what is going on is a network problem.  If there are any faults that send errant electrical signals on the network wires then all sorts of wacky things start happening and theres almost nothing related between them.  There are 2 things that can cause that, a blown module, or an intermittently shorted out Contoller Area Network wire.  It could be you ECM but if any module went bad it would probably give you the same symptoms (or at least similiar ones).  I would take it to your dealer and have them look at it.  An independent shop isn't gonna have the right equipment to read CAN diagnostics correctly, and even if they do by chance they will have no idea of the fault-tracing because they're simply not gonna be familiar with it.  These kind of problems take a while to find so it may get expensive.  Get an initial estimate of the time its gonna take to find the problem before you get too invested in the car.  

Also you can look for shorted CAN wires yourself.  I have seen incedents of rats getting under the hood and chewing throught them.  It is a twisted pair, green and white wires.  

James