Fuel Injector Driver Module (CNG): Description and Operation

The NGV module assembly:
^ consists of a 60-pin module, a bracket, a marine cover and four marine cover retainers.
^ houses the unique electronics required for natural gas fuel systems.
^ is located on the center radiator support, behind the radiator grille.

The NGV module carries out the following functions:
^ injector drivers: the NGV module accepts eight unmodified injector signals from the Powertrain Control Module (PCM) and allows a peak-and-sustain current to flow through the injector solenoids.

NOTE: No injector calculations are carried out; the injector driver output is not determined by the NGV module.

^ fuel gauge driver: the NGV module uses fuel tank temperature and fuel tank pressure inputs to calculate the density of the fuel; a look-up table is used to determine the output signal to the low fuel warning switch (through a combination of discreet resistors), which drives the fuel gauge located in the instrument cluster.
^ power and ground supply: the NGV module supplies power to the instrument cluster components on Circuit 231 (BK/YE) when the ignition switch is in the RUN and START positions. Ground for the fuel gauge, the low fuel level warning switch and the voltmeter is supplied on Circuit 570 (BK/WH). Circuit 231 (BK/YE) also supplies power to the following components in the instrument cluster:
- low fuel indicator
- CHECK ENGINE indicator (Malfunction Indicator Lamp [MIL])
- speedometer
- temperature gauge
- oil pressure gauge
- Anti-lock Braking System (ABS) indicator
- overdrive (OD) OFF indicator
- brake warning indicator
- AIR BAG warning indicator
- fail-safe cooling indicator