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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 54 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (2 Of 3)) >> Diagnostic Information and Procedures >> DTC P1089 >> Circuit/System Testing

Circuit/System Testing

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.
NOTE:
  • You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition ON, command the fuel pump ON and OFF with a scan tool. Verify the fuel pump turns ON.
    • Go to next step: If the fuel pump turns ON 
  2. Verify there are no fuel system leaks. Refer to Fuel Leak Diagnosis .
    • If a fuel leak is found 

      Repair as necessary.

    • Go to next step: If a fuel leak is not found 
  3. Ignition OFF, disconnect the fuel supply outlet hose at the fuel filter assembly.
  4. Install the CH-37287-1A  Fuel Pressure Gauge Adapter and attach the CH-48027  Digital Fuel Pressure Gauge.
  5. Ignition ON, verify the fuel pressure is between 414-550 kPa (60-80 PSI).
    • Go to next step: If within 414-550 kPa (60-80 PSI) 
  6. Reassemble the outlet hose at the fuel filter assembly.
  7. Verify that no fuel injector nozzles are stuck in the open position. Refer to Fuel Injector Balance Test and perform the procedure under Circuit/System Testing.
    • If a fuel injector nozzle is stuck open 

      Replace the appropriate Q17 Fuel Injector.

    • Go to next step: If a fuel injector nozzle is not stuck open 
  8. Verify fuel pressure regulator 1 or fuel pressure regulator 2 is not sticking. Refer to Fuel Pressure Regulator Diagnosis .
    • If fuel pressure regulator 1 or fuel pressure regulator 2 is sticking 

      Replace the appropriate Q18 Fuel Pressure Regulator.

    • Go to next step: If fuel pressure regulator 1 or fuel pressure regulator 2 is not sticking 
  9. All OK.
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