hi
just had the same problem.
here's how to fix
1. press code button on right hand side of radio
2. wait until the radio station lcd changes to 0000
3. there is a device on steering column, read 4.
on the bottom of this is a small square button, press this once/quickly and the first 0 will start blinking, insert your code number,and press the square button again quickly, it will automatically move to the next 0 continue until the numbers are all computed. press and hold the square button.
4. on r/hand side of steering column [under wheel] is a gadget that increases vol/dec vol/ mute. under this item is a wheel, turn this left or right to put correct number of your code.
i hope this helps, it worked with our car.
david, September 2006