Theory Of Operation

There are two unique Fuel Injector Relay assemblies that supply voltage to the CNG and gasoline Fuel Injectors. One relay is used for the CNG injectors and the other is used for the gasoline injectors. The ASD Relay provides 12 volts to each relay. Two low side drivers inside the Powertrain Control Module (PCM) provide the grounds for each relay. Each Fuel Injector Relay assembly consists of four internal dual throw switches. When the PCM determines which fuel mode the vehicle is to be operating in, it will close the low side driver for the control circuit on the appropriate relay providing a constant 12 volts to the Fuel Injectors.