Failed Emission

Check this link. http://www.obdii.com/connector.html check for voltage and ground on pins 16 and 5 only, check that the pins in the connector are not damaged, after that someone experienced with VW should look at the car for you. As Roy said unless a scan tool can connect and read codes they will not do a smog on your car.

you must be able to communicate witht he cars computer. it may or may not be related to your radio installation. a shop wil be able to narrow your issue down to the failed system. Roy