2004 xc70 help help help
 

About 6 months ago, my car lurched and stopped, lost all instrument panel lights. Waited 5 minutes car started (still no instrument panel lights or power windows, locks, etc). Got car home turned it off and it was dead. Had it towed to dealership, they connected to diagnostic machine and received neither negative/positive codes. Tech said he really couldn't say what is wrong but that car started up and was running fine. Instrument panel shows messages that say things are wrong, like air bag malfunction light, needs washerfluid, ABS brakes, etc. but that as far as he could tell car was fine and he recommended replacing CEM but wanted me to know he wasn't positive based on diagnostic results. Car ran fine for about 6 months and it happend again. After car sat for 3 days it started right up and ran fine again for another few months and it has happened again. I don't want to pay 1200.00 for a part that might not correct my problem. Can someone help me please