Morning folks.

I bought a code reader from Euro Car Parts yesterday to read a fault code on my 2004 1.9tdi Caddy.

The reader won't connect to the car for some reason. It lights up when plugged in so it's getting power.

I've tried it with the stereo on and off, as it's aftermarket and I've read that it might interfere.

Anything I'm obviously missing. This is my first time attempting a go on the ECU/OBDii side of things.