My renault clio (Y-reg 1.2) manual says that if you enter the code incorrectly, you should wait for one minute (with the set switched on) and it will reset itself, allowing you to re-enter the code. if you enter it incorrectly again, you will need to wait for 2 minutes, then 4, 8, 16 up to 32.
If you know the code this shouldn't be a problem.
Jamie, July 2010