Navigation DVD Drive - Device Fault

[d1s]

Hello
I've (sort of) successfully completed a DVD Navigation retrofit into my A6, but the navigation MMI screen shows 'Please check Navigation DVD'. I've tried a dew different DVDs with no success.
A VCDS scan shows the error 'Device Fault'.
Does this mean the unit is faulty?
I purchased it second hand from eBay.
Any suggestions on how to fix it?
Thanks

 

[B5NUT]

It's faulty and should be returned. If it was a dirty laser you would get a read error shown in VCDS.

 

[d1s]

Thanks for your quick reply