need code for clarion PU9990B?

Ive tried the
--------------------------------------------
Add 1 to the first digit
Add 2 to the second digit
Add 3 to the third digit
Add 4 to the fourth digit

As you can only enter numbers 1 to 6 on the radio, for any numbers greater than 6, subtract 6
---------------------------------------------
Using this algorithm 8085 = 3253 but it dosent seem to take it. Some places on the net say this only works for the codes that start with C7 mine starts with CL.

Anyone know if there is a diffrent algorithm that would work for the ones that start with CL?

Thanks

Gafyn
September 2010