The information below will eliminate 97% of Sony NW-HD Adapter/Car Kit errors or "non functioning product" issues.
Quick Diagnostic Procedures: Reinitialize your Sony NW-HD Adapter/Car Kit This basically means to reset your Sony NW-HD Car Kit with respect to its communication with your radio.
To do this, remove your keys from your ignition and then disconnect your iPod adapter from your radio.
Leave it disconnected for 15 minutes then reconnect to the rear of your car radio.
Now, switch the ignition on and try for correct operation.
Here's what to do if your Sony NW-HD Adapter/Car Kit is used in conjunction with a CD interface adapter.
Reinitialize your Sony NW-HD Adapter/Car Kit.
As in the first case, it basically means you should reset your Sony NW-HD Car Kit with respect to its communication with your radio.
To do this remove your keys from the ignition and then disconnect the CD interface adapter from the rear of your car radio.
Also, disconnect the Sony NW-HD Adapter from the CD interface adapter.
Leave all disconnected for 15 minutes then, first, reconnect the Sony NW-HD Adapter to the CD interface adapter and then connect this into the rear of your radio.
You can then switch the ignition on and see if everything works well.
The above steps eliminate approximately 97% of Sony NW-HD Adapter/Car Kit issues.
However, if yours still persists, please call a car audio expert or submit a support ticket to the customer support of the shop you bought your Sony NW-HD Adapter/Car Kit from.
There may be a hardware fault that has to be resolved.