Car intermittently displaying a 4WD fault. Car still operational although have notice mileage is down. Dealer tried several times to replicate and finally got system to identify an issue with control unit and wants $1200 for parts and labor. They are saying it's a random fault due to low-voltage which is causing the intermittent fail. Wondering if anyone else has had a similar issue?

Cars & Trucks - Porsche - Cayenne - 2005 Porsche Cayenne