[A8] Sunroof power-up failure info, and a new fix
martin.karo at verizon.net
Fri Oct 5 17:42:44 PDT 2007
After a dead battery jumpstart or battery replacement, several of us have had the sunroof go all the way back by itself, and lock open. I had not only that problem, but also could not crank it closed with the emergency crank. I drove it over to the Audi dealer, where the head mechanic (who at least sounded like he knew what he was talking about) said that the reason this happens is that when the sunroof ecu sees a very low current and then gets a surge, it interprets that as an open signal. Based on that, I would suggest either pulling the fuse or disconnecting the sunroof motor connectors before jump-starting a dead battery.
Worse, the dealer could not close the sunroof either (they stripped the crank splines trying), decided the fix was to replace the motor, graciously offered to do that for $700, and scheduled the repair for next Tuesday. They sent me home with the roof still jammed open. I was not happy; it occasionally rains in Pennsylvania.
When I got home I simply dropped the sunroof motor. Three easy small torx bolts and it's out. With the motor gone, the sunroof could be slid closed by hand (I used a screwdriver in the rear tracks to pop the rear of the panel up into the closed position). Then, while the motor was still out, I reconnected the switch and power plugs. The motor spun like a top. I cycled the switch a few times until the motor was at the closed position when the switch read closed, then bolted it back in place. Voila. Worked perfectly. Took about ten minutes soup to nuts.
Two points from this: one, it may be a good idea to keep a 3x torx screwdriver in the car, in case your roof gets stuck open and the crank won't close it, so you can slide it closed by hand in a real emergency. Two, it's a sad day when the customers figure out how to fix the cars better than the brand experts. Why do the A8 owners get treated as the red-headed stepchildren of Audi's customer base?
1998 A8Q 90k
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