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Home >> Chevrolet >> 2019 >> Cruze Premier, 4D Hatchback >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Controls And Fuel - 1.6L (LH7) Diesel - Diagnostic Information And Procedures (P208A-P31BF) And Symptoms) >> Diagnostic Information and Procedures >> Fuel System Diagnosis - High Pressure Side >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Test 1

  1. Ignition/Vehicle & All vehicle systems - Off
  2. NOTE:
    • In order to perform step 2 - 5, the fuel temperature must be greater than 10°C (50°F) or misdiagnosis may occur.
    • Leave the electrical connector connected.
  3. Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
  4. Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
  5. Engine - Cranking - Until air is purged from the hose
  6. Engine - Cranking - For 15 s

    Verify the container contains less than 15 mL (0.5 US fl oz)

    • If 15 mL (0.5 US fl oz) or greater 

      Replace the component: Q18B Fuel Pressure Regulator 2

    • Go to next step: If less than 15 mL (0.5 US fl oz) 
  7. Ignition/Vehicle & All vehicle systems - Off
  8. Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
  9. Disconnect the electrical connector: Q17 Fuel Injector - All
  10. Disconnect the component: Fuel Return Hose @ Q17 Fuel Injector - All Refer to: Fuel Injector Replacement

    Plug the fuel return hose(s) in order to prevent leakage. @ Diesel Fuel Separator

  11. Engine - Cranking - For 15 s
  12. Verify the condition does not exist: Leaking @ Q17 Fuel Injector
    • If a condition exists 

      Replace the appropriate component: Q17 Fuel Injector

    • Go to next step: If no condition exists 
  13. Ignition/Vehicle & All vehicle systems - Off
  14. Install the component: Fuel Return Hose
  15. NOTE:

    Perform the following test for all 4 components. - One at a time

  16. Perform the following steps:
    1. Disconnect the electrical connector: Q17 Fuel Injector - All
    2. Disconnect the electrical connector: E12 Glow Plug - All - Secure and insulate the connection using electrical tape.
    3. Remove the component: E12 Glow Plug - One at a time
    4. Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
    5. Engine - Cranking - For 6 s

      Verify the condition does not exist: Fuel On Shop Towel

    • If a condition exists 

      Replace the appropriate component: Q17 Fuel Injector

    • Go to next step: If no condition exists 
  17. Test or replace the component: G18 High Pressure Fuel Pump

Test 2

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Perform the following procedure/test: Fuel Injector Balance Test with Scan Tool 

    Verify the procedure/test passes.

    • If the procedure/test does not pass 

      Replace the component that failed the test: Q17 Fuel Injector

    • Go to next step: If the procedure/test passes 
  3. Engine - Idling
  4. NOTE:

    Fuel Rail Pressure - Maximum @ At Idle Speed = 120 MPa (17405 PSI)

  5. Perform the scan tool control function: Fuel Rail Pressure - Increase & Decrease

    Verify the following parameters are within 2000 kPa (290 PSI) of each other:

    • Desired Fuel Rail Pressure
    • Fuel Rail Pressure Sensor 1
    • If not within 2000 kPa (290 PSI) of each other 

      Replace the component: Q18A Fuel Pressure Regulator 1

    • Go to next step: If within 2000 kPa (290 PSI) of each other 
  6. Ignition/Vehicle & All vehicle systems - Off
  7. NOTE:
    • In order to perform step 6 - 9, the fuel temperature must be greater than 10°C (50°F) or misdiagnosis may occur.
    • Leave the electrical connector connected.
  8. Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
  9. Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
  10. Engine - Idling - Until air is purged from the hose
  11. Engine - Idling - For 15 s

    Verify the container contains less than 15 mL (0.5 US fl oz)

    • If 15 mL (0.5 US fl oz) or greater 

      Replace the component: Q18B Fuel Pressure Regulator 2

    • Go to next step: If less than 15 mL (0.5 US fl oz) 
  12. Ignition/Vehicle & All vehicle systems - Off
  13. Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
  14. Disconnect the electrical connector: Q17 Fuel Injector - All
  15. Disconnect the component: Fuel Return Hose @ Q17 Fuel Injector - All Refer to: Fuel Injector Replacement

    Plug the fuel return hose(s) in order to prevent leakage. @ Diesel Fuel Separator

  16. Engine - Cranking - For 15 s
  17. Verify the condition does not exist: Leaking @ Q17 Fuel Injector
    • If a condition exists 

      Replace the appropriate component: Q17 Fuel Injector

    • Go to next step: If no condition exists 
  18. Ignition/Vehicle & All vehicle systems - Off
  19. Install the component: Fuel Return Hose
  20. NOTE:

    Perform the following test for all 4 components. - One at a time

  21. Perform the following steps:
    1. Disconnect the electrical connector: Q17 Fuel Injector - All
    2. Disconnect the electrical connector: E12 Glow Plug - All - Secure and insulate the connection using electrical tape.
    3. Remove the component: E12 Glow Plug - One at a time
    4. Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
    5. Engine - Cranking - For 6 s

      Verify the condition does not exist: Fuel On Shop Towel

    • If a condition exists 

      Replace the appropriate component: Q17 Fuel Injector

    • Go to next step: If no condition exists 
  22. Test or replace the component: G18 High Pressure Fuel Pump