Natural Gas Vehicle Module

Natural Gas Vehicle (NGV) module has 2 functions. The first function is to operate fuel injectors and is referred to as Injector Driver Module (IDM). The second function sends a fuel level indicator signal to drive the fuel gauge and is called Fuel Indicator Module (FIM). IDM vehicle fuel indicator driver signals are based on PCM fuel injector driver signals and are controlled directly by corresponding injector drivers in PCM. IDM must be used to provide NG fuel injectors with the required high current necessary for proper operation. The greater demand of fuel injector current warrants an increased size of injector driver and increased heat dissipation. Given these conditions, PCM would not be suitable for location of these drivers. IDM closely resembles 60-pin EEC-IV PCM module in appearance. See NATURAL GAS VEHICLE MODULE LOCATION  table.

IDM injector drivers are capable of controlling amount of current flow to each NG fuel injector. Once fuel injector is open, IDM NG fuel injector driver will reduce current flow to a sufficient amount to continue to hold fuel injector open in an effort to reduce heat. If IDM driver does not detect required peak current to initially open NG fuel injector within a specified amount of time, IDM driver will drop current to fuel injector hold open current. The FIM is not part of the powertrain control subsystem.