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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 508 (Engine Controls/Fuel - 5.3L, 6.0L, 6.2L - DTC P0420 To DTC P3449 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel System Diagnosis (Without FPCM) >> Circuit/System Verification

Circuit/System Verification

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    NOTE:
    • Inspect the fuel system for damage or external leaks before proceeding.
    • Verify that adequate fuel is in the fuel tank before proceeding.
    • The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
  1. Ignition ON, command the Fuel Pump Relay ON with a scan tool. You should hear the fuel pump turn ON and OFF.
  2. Ignition OFF, all accessories OFF, install the CH-48027  digital fuel pressure gauge. Refer to Fuel Pressure Gauge Installation and Removal .
  3. Ignition ON, command the Fuel Pump Relay ON with a scan tool. Verify the fuel pressure is between 345-414 kPa (50-60 psi) and remains steady for 5 minutes.