Did they both work once? Has the problem key been dropped?
We have a 2000 kangoo. It has a single button remote, the key also contains a 'transponder' to activate the immmobiliser. The spare key we got with the car would lock and unlock with the button but would not start the car (immobiliser light flashes very fast). I took the key apart and found a component (pick up
) broken off the board and badly damaged. I had to rewind the
(the number of turns is critical as it forms a tuned circuit) and refit it. But after that it worked fine. A bit of work but cheaper than buying a new key and getting it programed to the car.
If yours is the same type of key it can be repaired if that's the fault. Let me know