A car diagnostic test can reveal a number of problems associated with your vehicle\'s transmission, oil tank, gas tank, exhaust system, or other components. Complete Auto Care\'s car engine diagnostic services can help identify the cause of your engine problems. Get your engine ... What areas of the car can be tested? Diagnostic tests can reveal problems within a car\'s engine, transmission, exhaust system, brakes, and other major components, as well as performance issues with the fuel injector, air flow and coolant, ignition coils, and throttle. A Car Diagnostic Test Identifies your Automotive problems. A car diagnostic test provides a quick and accurate assessment of your vehicle. Technicians will scan your vehicle\'s onboard computer, document any diagnostic trouble codes, and check for service notifications issued by your vehicle\'s manufacturer