In RAGE 2, your vehicle is your best companion. You will use it for both exploration and combat. There are many vehicles in RAGE 2. Some of them can be upgraded to be even more useful to you.
Your vehicle can get damage either during exploration or combat. If you don't do anything with it, the vehicle will explode.
Don't worry when this happens, you will still be able to recall it.
To repair a vehicle, leave it and stand in front of the hood. Do that and you will see a new interaction.
Hold the right key/button and your character will repair the vehicle. Remember, not every vehicle can be repaired - Icarus is one of them.