As far as I am concern, there is no cheats helping to maximize the skill of a Sim.
However, in ModThesims.info (MTS), a creator has released a CC which will help improve the speed in which a Sim learns a skill.
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Just use the boolprop cheat in the neighborhood and go to your skills and just click and drag on them.
maxmotives
There are cheats in The Sims 2: Castaway: Max Skills, All Plans, All Relationships, Maximum food and resources. But first, you have to unlock the Cheat Gnome. To unlock the Cheat Gnome: Left Trigger Right Trigger Up X Right Trigger
Yes there is. you need to ctrl shift c and enter boolProp testingcheatsEnabled true and shift left click on a sim and there are options and if you click on skills iit says max all and click on tht and your skills will be maxed
Square 4 times, Left Trigger: Max current Food and Resources