Hi, my 97' passat is due for a smok check. will the faulty air beg ECU (Airbag Warning Light stay on) causes the smok check to fail?

Thanks in advance.

Hello:
You will need ot check with your state requirements for this probelm. Each state is different when it comes to inspection requirements. In NY, an airbag light illumination will require a rejection notice be issued to the owner for documentation purposes only, but the vehicle will still pass the inspection.
A call to DMV will most likely be your best answer as many shops tend to make up the answers they don't know