Late model Volvo resources?

My mom drives an '06 S80 which is no longer under warranty. The car was hard to start yesterday and today is DOA and stuck in her garage. The only fault code showing is "U0073 - Control Module Communication Bus Off" and some Google searching hasn't turned up anything particularly useful to help troubleshoot the problem. I've also searched half a dozen Volvo boards, but the advice there generally tends toward "see what the dealer says". Are there any more through Volvo tech resources out there? Thanks!

I'm guessing you've already tried Swedespeed? Maybe find and independent shop? You should be able to find one that has a computer diagnostic set-up that can do a bit more than a typical code reader.

Have you tried turning the control module communication bus back on? The problem sounds like it might be related to the control module communication bus somehow.

No, I have absolutely no idea. Sounds serious. If you need to throw parts at it, I'd suggest an ECU or two.

Brickboard may be able to help but they're more older models. Stupid question - did you check battery voltage? All sorts of weird electrical things happen when batteries die, and if it's an '06 that now 4-year-old battery may be done for. Other than that, I'd try unplugging everything connected to the ECU, cleaning all the contacts and carefully re-plugging in everything, provided that it doesn't require major disassembly to get to the ECU.

This turned up on a quick google search: http://forums.swedespeed.com/zerothread?id=117872 Not sure if it helps or hurts that his dealer was just throwing $$$$ 4-figure electronics modules at the problem.

I disconnected the battery, cleaned the terminals and checked each of the fuses. After reconnecting the battery, it started right up and the check engine was off. Mom was afraid of being stranded if it happened again, so we took it to the dealer anyway (at least I saved the $100 tow). The dealer tech said that the communications network on the car was faulty, so they flashed the control module with updated firmware and she should be good to go...

Sometimes I wonder if OEM's are building their on-board computer systems specifically to keep people coming back to the dealer for service at the expense DIY and independent repair facilities.

I hear you there. I just picked my car up from having another (this makes 3) $600 door handle installed. Dealer only beause it has to be programmed to the car with the $$$$$$ GT1 computer. Warranty ftw for now but all of the gadgets and toys on this car will definitely put me into the poorhouse sooner or later once the warranty runs out in 22k miles.

careful of the 'reflash'. I don't know anything about how this relates to cars, but reflashing a regular chip doesn't do anything unless the firmware was seriously troubled to begin with - peace of mind may be part placebo effect here...

nderwater wrote: Sometimes I wonder if OEM's are building their on-board computer systems specifically to keep people coming back to the dealer for service at the expense DIY and independent repair facilities.

Somewhat related - my trusted independant Volvo shop isn't yet prepared to pay the big bucks for the new VIDA system, required for '07+ cars. Most of those cars (mine included) are still under warranty, but not for much longer. My guess is that they will have to cave in eventually, but it is a big nut that will be passed on to their customers.

Bah, my Mom's car is having the same symptoms again. This time the dealer says it's the transmission control unit which is bad, making the rest of electrical system freak out... and wants another $1,300 to fix it. Is this a common problem? Would we be better off taking it to an independent shop?

(By the way I tried the SwedeSpeed forums, but that place is a ghost town.)