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Home >> Hummer >> 2009 >> H2 4D Utility Pickup >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 6.2L - Troubleshooting & Diagnosis >> Fuel System Diagnosis >> Circuit/System Verification

Circuit/System Verification

IMPORTANT:
  • Repair all fuel system related DTCs before performing this diagnostic
  • 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.
  • Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.
  1. Ignition OFF, all accessories OFF, install a CH-48027  . See Special Tools . Refer to Fuel Pressure Gage Installation and Removal .
  2. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 345-414 kPa (50-60 psi) and does not decrease more than 34 kPa (5 psi) in 1 minute.
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