I have a 2009 A4 Cabrio Quattro (2008 engine, etc.). My original key fob housing was not in good shape so I bought a new-looking one (uncut) from eBay. I moved the mechanical key and electronics from my old key fob to the new key fob.I followed the car manual’s instructions to code the key fob to the car. (It seemed to lose its programming in the exchange.) This involves putting the new key in the ignition, turning to “ON,” pushing the “Unlock” button, taking out, and pushing “Unlock” again.This did make the “new” key work on the doors, but it will no longer start the car. The car turns over for a second and “SAFE” appears in the speedometer display. This is the “Immobilizer.”My wife’s key still works fine.I did try to pair the new key’s electronics with the car before I went back to using my old key’s electronics.I read that there may be some ways to re-set the Immobilizer by leaving the key set to “ON” for ten minutes or by disconnecting the battery. There may be a VAG-COM way of resetting the immobilizer too.At this point, I don’t want to do anything fully immobilize the car since we live in a rural area.Suggestions?