You can rent an Ozonator from a rental shop that will permanently kill the odor. These are very powerful and can even get rid of the stench of rotting flesh or smoke damage from a building.
We had someone come out and use one on a used TT we once had. Cost us $150 and worked great.
Scott, Grace and Wesly
2003 Dodge 3500 4x4, 6 speed Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.
Find out the source then you can select the proper chemical. Cat pee in a hot car will curl your nose hairs, smells like dead fish. The only way to get that out was remove the carpeting. We sold the car