hi guys new here and new to golfs, bought a 2001 2.0 a few weeks ago and had a few problems with it running, so connected it to d900 obd2 reader to read the codes and clear them to see which ones would come back up, but none did. car was running well for a bit now problems started again, so connected obd2 reader again but now it wont establish a connection with the car any ideas why? any help appreciated thanks