If the radio is original to the van, then it will have had a little chat with the canbus and told it the code, the van will recognise the radio after a certain time and hence nor need for the code. I can't recall if you have to leave the radio on, or leave the ignition and the radio on, or just the ignition. Hopefully someone will confirm. It certainly works though as I don't have the code and have disconnected mine a number of times. So long as it's the original radio.