The Mobile Mechanic perk can be purchased from Harry in any Headquarters. It allows you to automatically repair your car for price that is 200% of the HQ repair, unless you upgrade the discount. The player can purchase the perk 9 more times for a maximum of a 100% discount. When you repair, damage will restore all the way up to the spec's maximum amount of damage.
A car that is damaged, which is seen using the Mobile Mechanic app.