After I installed two new police cars, which required me to edit the cavarations and vehicle meta, there isn't any engine or siren sound attached to that vehicle when I drive them in the game. Since I'm not new installing cars or other mods, I went back to look at both of the files that I edited and everything seemed to check out. So could some one tell me exactly what controls the audio attached to the car. For example is it the cavarations I need to fix or the vehicles meta.

thanks 

I found the solution 

25 minutes ago, connn911 said:

I found the solution 

What was the solution?

vehicles.meta, audioNameHash tag. It has to be set to one of the vanilla models, eg POLICE, the new car will then use all the sounds from that vehicle.

2 hours ago, Yard1 said:

vehicles.meta, audioNameHash tag. It has to be set to one of the vanilla models, eg POLICE, the new car will then use all the sounds from that vehicle.

That's the solution I found.