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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 94 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (3 Of 3)) >> Diagnostic Information and Procedures >> Fuel System Diagnosis >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect the fuel system for damage or external leaks before proceeding.
  2. Verify that adequate fuel is in the fuel tank before proceeding.
  3. Ignition ON, command the fuel pump relay ON and OFF with a scan tool.
  4. Verify the fuel pump turns ON and OFF with each command.
    • Go to next step: If the fuel pump turns ON and OFF 
  5. Crank the engine for 15 s while observing the Actual Fuel Rail Pressure parameter with a scan tool. The parameter should display at least 13 MPa (1885 psi). The Desired Fuel Rail Pressure and the Actual Fuel Rail Pressure should closely match each other.
    • If fuel pressure is less than 13 MPa (1885 psi) or the Actual and Desired Fuel Pressure parameters do not closely match 

      Refer to Circuit/System Testing

    • Go to next step: If fuel pressure is 13 MPa (1885 psi) or greater and the Actual and Desired Fuel Pressure parameters closely match 
  6. All OK.
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