Hello, new to the forums! I have an issue with my 06 R52S where the top will only go to sunroof open, then no more. No flashing lights or any attempt to go further. Searched google for this code to no avail, hoping someone has an explanation here!

28. CVM. Switch, arrester hook locked: short circuit to ground or open circuit.

Thanks!

 

make sure the rear parcel tray is making contact with the micro switch on the l/h side and the rear hood locking levers are fully locked, the micro switch can be a tricky one to see as the tray may be down but not operating the switch, this was a problem I had and had to put a piece of rubber tube on the end of the tray leg/part that makes contact with the switch as the tray had warped a bit and not making contact on some occasions
Russ

 

There's also a push button switch in the upper left side of the boot hatch frame. It's a short throw switch. I stuck a small chair leg pad on the boot hatch opposite with never an issue...so far.