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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 356 (Engine Controls And Fuel - 3.6L (LGX) - DTC P0446 To DTC P3436 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel System Diagnosis >> Circuit/System Testing

Circuit/System Testing

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Fuel Pressure Low

  1. Verify none of the conditions listed below exist:
    • Restricted fuel feed pipe
    • Restricted or plugged strainer
    • Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
    • If a condition exist 

      Repair as necessary.

    • If a condition does not exist 
  2. Test or replace the G12 Fuel Pump.

Fuel Pressure Leaks Down

  1. Ignition OFF, relieve the fuel pressure. Refer to Fuel Pressure Relief .
  2. Install the EN-37287  Fuel Line Shut-Off Adapters between the fuel feed pipe and the fuel rail.
  3. Open the valve on the EN-37287  Fuel Line Shut-Off Adapters.
  4. Ignition ON, command the Fuel Pump Enable On with a scan tool.
  5. Close the valve on the EN-37287  Fuel Line Shut-Off Adapters.
  6. Verify the Fuel Rail Fuel Pressure parameter does not decrease greater than 34 kPa (5 PSI) in 1 min.
    • If the fuel pressure drops 

      Replace the G12 Fuel Pump.

    • If the fuel pressure does not drop 
  7. Locate and replace the leaking Q17 Fuel Injector.

Fuel Pressure Drops OFF

  1. Verify none of the conditions listed below exist:
    • Restricted fuel feed pipe
    • Restricted or plugged strainer
    • Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
    • If a condition exist 

      Repair as necessary.

    • If a condition does not exist 
  2. Test or replace the G12 Fuel Pump.
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