Good afternoon! Read through quite a few posts on here looking for some answers, although helpful it's a little discouraging when reading about the issues owners are having!! Anyhow, I own a 2004 T6 XC90 with approx 125k miles. About 2 months ago, while driving on the interstate, at night, experienced an electrical failure briefly, all dash, radio, a/c, and headlights cut out and then back on as quick as they went out. This happened again a few time on the return trip home. After that, never experienced it again. This seemed to happen after opening the sun roof, which we rarely do. I have read about the drain issues in other posts. My more recent issue was yesterday. We live in VA, temp was in the high 80's - 90's, my wife after shopping, the car would not start. Here's what was happening:
Turn the key to start, hear one click under hood, dash lights come on, gauges move up, then return to home position. Lights on dash go off except the check engine. Tried to jump start, no luck. Had vehicle towed. The other weird part is that neither of the key fob remotes would lock/unlock the doors when pressed. Later that evening, when the remote was attempted, only interior lights would come on or off, til now, the car still won't start. Any experiences and/or suggestions are greatly appreciated. Thanks!!

 

Follow up: after doing some online research and reading, I took someone's suggestion and disconnected the neg battery terminal and left unhooked for 30 minutes. Reinstalled it, the vehicle started, and as mentioned in first post, now the key fob remotes work to lock/unlock the doors. I am now getting an SRS Airbag Failure message?

 

Looks like you issues with both CAN buses hi speed and low one.
That can be faulty CEM module. To be sure you to heat it up using hairdryer. If CEM is faulty you will get the issue reproduced in some minutes heating. thisthis topic have references how to get to CEM module an remove it.

 

Just received word back from the Volvo specialist, after diagnosing, 22 error codes came back. Said the CEM is not communicating.....something to that effect, anyhow, his results seem in line with the posts and responses in this and other forums. Thanks for your input! Oh, the cost for replacement is just over $1300. It would be nice if Volvo would cover at least part of the cost for their poor design, and I certainly hope that by replacing it that it doesn't re occur!!

 

You can get CEM rebuilt for a cheaper price. Ask Xemodex company for that.

 

I may have pursued that avenue had I known earlier, as I have already authorized the work to be completed. I guess I knew it would cost me one way or the other, and everyone appreciates saving $$, I'm equally satisfied finding a reliable/trustworthy auto tech that isn't willing to take advantage of a person. On another note to my follow ups, he did question the windshield replacement and the fact that it wasn't a Volvo windshield, suggesting that evidence showed leaking into where a couple of relays are, thus needing replacement as well. I did notice that a couple of press in tabs were loose/missing that fasten the cowling below the windshield?? So makes me wonder? Although the windshield is in good condition, just wondering if it would be worth taking back to Volvo to have a new one installed by them??

 

Forgot to mention that they are going to clean the sunroof drains and check the windshield/cabin for leaks