Technician A says the on-board self-diagnostics test mode procedures should be conducted on a cold engine. Technician B says many diagnostic trouble codes (DTC) will monitor items only when the engine control system is in closed loop. Who is right?

ASE identifies engine performance as an individual service area. The engine performance service area involves these systems. Ignition system:  components that ignite the fuel and air mixture at the proper time to create maximum power and minimum emissions. The fuel system: Components that transfer fuel from the fuel tank to the engine cylinders in the proper amounts so as to create maximum power and minimum emissions. The exhaust system: Components that remove combustion by-products from the engine. The emission control system: Components that reduces the amount of harmful gases emitted from... Show more

ASE identifies engine performance as an individual service area. The engine performance service area involves these systems. Ignition system:  components that ignite the fuel and air mixture at the proper time to create maximum power and minimum emissions. The fuel system: Components that transfer fuel from the fuel tank to the engine cylinders in the proper amounts so as to create maximum power and minimum emissions. The exhaust system: Components that remove combustion by-products from the engine. The emission control system: Components that reduces the amount of harmful gases emitted from the vehicle.

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