Theory Of Operation

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

The Fuel Injector is supplied power from the Automatic Shut Down (ASD) Relay Output circuit. The Powertrain Control Module (PCM) provides a Pulse Width Modulated (PWM) ground to the injector's solenoid coil to inject pressurized fuel just upstream of each cylinder's intake valve. Each injector receives a unique pulse width based on that cylinder's fuel requirements. The PCM determines this fuel requirement by monitoring engine operating parameters through various sensors and then calculating the appropriate amount of fuel to be injected. The optimum amount of injected fuel depends on conditions such as engine and ambient temperatures, engine speed and workload, and exhaust gas composition.

The Powertrain Control Module (PCM) monitors the continuity of the injector circuits as well as the voltage spike created by the collapse of the magnetic field in the injector coil.