S15/T15 Sonoma P/U 2WD L4-2.2L VIN 5 Flex Fuel (2001)
Fuel Pressure: Testing and Inspection
CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) will turn ON the in-tank fuel pump, with the ignition ON. The in-tank fuel pump will remain ON as long as
the engine is cranking or running, and the PCM is receiving ignition reference pulses. If the PCM does not detect any ignition reference pulses, the
PCM turns the fuel pump OFF 2 seconds after the ignition is turned ON.
The in-tank fuel pump is an electric pump that is attached to the fuel sender assembly. The fuel pump is designed to provide fuel at a pressure above
the pressure that is needed by the fuel injectors. A fuel pressure regulator, which is part of the fuel filter assembly, keeps the fuel available to the fuel
injectors at a regulated pressure. Unused fuel is returned to the fuel tank by a separate fuel return pipe.
TEST DESCRIPTION
Steps 1-5
