2004 S60 DIM, CEU?

[Bartlett S60]

I have a 2004 S60 that has had an intermittent problem since I purchased it. I first thought it was the DIM but I am not so sure now. The car on the highway will act like the car suddenly downshifts. Instruments all fluctuate. This may happen several times in a few minutes. All dash messages will flash on on. Sometimes all gauges go out. I may get error messages like "ABS brakes problem pull car over". The first time this happened, the SRS air bag warning came on and has been on ever since. This problem usually will go away by shutting off the car and restarting. Problem may stay away for months. This last time it was real bad. Happened in fast heavy moving traffic. I could not pull over safely. Eventually the gauges all went out. The car ran fine so I drove it for an hour this way. I learned the following:
Turn signal signals and flashers didn't work. Wipers worked but the parking feature did not. Windshield washer also didn't work. Windows did not work nor did the remote control for the mirrors. Car shifted sluggish. I have a transmission problem also. It is shifting between first and second hard. I was planning on an oil flush. This helped once before. When this problem occurred the transmission felt sluggish but it did not shift hard as was normal. I suspect it had gone into a limp mode. Near home I shut off the car and restarted. Everything went to normal. The transmission felt rougher than normal in shifting but after a few miles it smoothed out somewhat. Sort of like it re-adapted itself. Does this sound like a CEU problem? Could the DIM cause the windows and turn signals to stop working? Any suggestions appreciated.

[bugeye]

Sounds very similar to out XC70. I read the CEM overheats and fails intermittantly. I removed the CEM and sent to XeMODeX. Not a hard removal, just above the drivers left foot. About $600 later, car runs normal. I was not willing to have family stranded in winter possibly hundreds of miles from home. I don't work for XeMODeX, just a pleased customer. XeMODeX will transfer all info to a rebuilt CEM with a heat sink. Easy plug and play and pay. Doing a couple transmission drain/fills with Mobil 3309 can't hurt.

[doublebug]

If that is CEM it can be proved by using hairdryer.
CEM usually clicks (relays) before complete hang. (in a case of 2003-2004 MY. 2005 MY is completely different)
But depending on error codes there can be other faulty modules.

[Bartlett S60]

Thanks for the feedback. So this is more likely the CEU and not the DIM?