Circuit/System Testing

Test 1

1. Ignition/Vehicle - Off
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.
2. Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
3. Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
NOTE:

Do NOT use the following tool or the incorrect test results will occur: Remote Start Switch

4. Engine - Cranking - Until air is purged from the hose
5. 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) 
6. Ignition/Vehicle - Off
7. Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
8. Remove the component: F86UA Fuse@X50A Engine Wiring Harness Junction Block
9. Disconnect the component: Fuel Injection Fuel Return Pipe @ Q17 Fuel Injector - All - Refer to: Fuel Injector Fuel Return Pipe Replacement

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

NOTE:

Do NOT use the following tool or the incorrect test results will occur: Remote Start Switch

10. Engine - Cranking - For 15 s
11. 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 
12. Ignition/Vehicle - Off
13. Install the component: Fuel Injection Fuel Return Pipe
NOTE:

Perform the following test for all 6 components. - One at a time

14. Perform the following steps:
    1. Remove the component: F86UA Fuse@X50A Engine Wiring Harness Junction Block
    2. Remove the component: F5BA Fuse@X50B Battery Distribution Engine Compartment Fuse Block
    3. Disconnect the electrical connector: E12 Glow Plug
    NOTE:

    The component must be discarded whenever removed and replaced with a NEW component:

    4. Remove the component: E12 Glow Plug - One at a time
    5. Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
    6. Engine - Cranking - For 6 s

       Verify the condition does not exist: Fuel @ Shop Towel

    • If a condition exists 

      Replace the appropriate component: Q17 Fuel Injector

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

Test 2

1. Engine - Idling
2. Perform the following procedure/test: Cylinder Power Balance Test 

   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. Ignition/Vehicle - Off
NOTE:
• In order to perform step 4 - 7, the fuel temperature must be greater than 10°C (50°F) or misdiagnosis may occur.
• Leave the electrical connector connected.
4. Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
5. Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
6. Engine - Idling - Until air is purged from the hose
7. 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) 
8. Ignition/Vehicle - Off
9. Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
10. Remove the component: F86UA Fuse@X50A Engine Wiring Harness Junction Block
11. Disconnect the component: Fuel Injection Fuel Return Pipe @ Q17 Fuel Injector - All - Refer to: Fuel Injector Fuel Return Pipe Replacement

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

NOTE:

Do NOT use the following tool or the incorrect test results will occur: Remote Start Switch

12. Engine - Cranking - For 15 s
13. 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 
14. Ignition/Vehicle - Off
15. Install the component: Fuel Injection Fuel Return Pipe
NOTE:

Perform the following test for all 6 components. - One at a time

16. Perform the following steps:
    1. Remove the component: F86UA Fuse@X50A Engine Wiring Harness Junction Block
    2. Remove the component: F5BA Fuse@X50B Battery Distribution Engine Compartment Fuse Block
    3. Disconnect the electrical connector: E12 Glow Plug
    NOTE:

    The component must be discarded whenever removed and replaced with a NEW component:

    4. Remove the component: E12 Glow Plug - One at a time
    5. Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
    6. Engine - Cranking - For 6 s

       Verify the condition does not exist: Fuel @ 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 Fuel Pump - High Pressure