Is there a max all motives cheat for sims 2 pets?

No sorry there is no motive cheat on the sims pets. Edit: There is none for Sims Pets, but there is one for Sims 2 Pets. It is 'maxMotives', also type in 'help' in the Sims 2. That will give you a large list of cheats.

Note: Must be in Sims 2, or it will not work.