Energizing the Fuel Pump

All of the fuel system tests will require operation of the fuel pump to measure pressure, evaluate pressure decay, or perform the pressure at calibrated flow tests.

Although the fuel pump can be controlled with the ignition, this is fairly awkward since:
^ Pump is only energized for 2-3 seconds at Key On (and then a wait of 10 seconds is required after Key Off before the pump can be powered again).
^ Some tests are run with vehicle on hoist with control of pump under car required, and
^ Pressure at flow tests require pump to run for 10-20 seconds.

The Scan tool provides control of the fuel pump at the technicians finger-tips. The tool will run the pump for 30 seconds after the On command. This timer will then shut the pump Off.

NOTE: Once the fuel pump is commanded On with the Scan tool it will be energized for 30 seconds before it times out and returns to the Off status. Do not leave the vehicle unattended while running any of the system tests with the pump On.

The Scan tool also controls the pulsing of the injectors and pressurizing the system during the Injector Balance Test 8.

Operating the Fuel Pump/Injector Balance Test
Control of the fuel pump and injector are under the SPECIAL FUNCTIONS menu.
^ Once in SPECIAL FUNCTIONS, select POWERTRAIN.
^ Select FUEL SYSTEM