C 1500 Truck 2WD V6-4.3L VIN W (1996)
Engine Controls (Fuel Pump 4.3L)
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, the Vehicle Control Module (VCM) turns ON the in-tank fuel pump. The in-tank fuel pump remains ON as long
as the engine is cranking or running and the VCM is receiving the distributor reference pulses. If there are no reference pulses, the VCM shuts off the
fuel pump within 2 seconds after the ignition ON or the engine stops.
Should the fuel pump relay or the 12 volt relay drive from the VCM fail, the fuel pump receives a supply current through the oil pressure switch backup
circuit. The fuel pump test terminal is located in the driver's side of the engine compartment. When the engine is stopped, applying the battery voltage to
the test terminal can turn on the fuel pump.
DIAGNOSTIC AIDS
