Circuit/System Testing
Test 1
- Ignition/Vehicle & All vehicle systems - Off
- 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.
- Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
- Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
- Engine - Cranking - Until air is purged from the hose
- 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)
- If 15 mL (0.5 US fl oz) or greater
- Ignition/Vehicle & All vehicle systems - Off
- Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
- Disconnect the electrical connector: Q17 Fuel Injector - All
- 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
- Engine - Cranking - For 15 s
- 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
- If a condition exists
- Ignition/Vehicle & All vehicle systems - Off
- Install the component: Fuel Return Hose
- Perform the following steps:
- Disconnect the electrical connector: Q17 Fuel Injector - All
- Disconnect the electrical connector: E12 Glow Plug - All - Secure and insulate the connection using electrical tape.
- Remove the component: E12 Glow Plug - One at a time
- Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
- 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
- Test or replace the component: G18 High Pressure Fuel Pump
Perform the following test for all 4 components. - One at a time
Test 2
- Ignition/Vehicle & All vehicle systems - Off
- 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
- If the procedure/test does not pass
- Engine - Idling
- 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
- Ignition/Vehicle & All vehicle systems - Off
- 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.
- Disconnect the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2 & Plug the fuel return hose(s) in order to prevent leakage.
- Install suitable hose to the component: Outlet @ Q18B Fuel Pressure Regulator 2 & Place the other end of the hose into a suitable container.
- Engine - Idling - Until air is purged from the hose
- 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)
- If 15 mL (0.5 US fl oz) or greater
- Ignition/Vehicle & All vehicle systems - Off
- Install the component: Fuel Return Hose @ Q18B Fuel Pressure Regulator 2
- Disconnect the electrical connector: Q17 Fuel Injector - All
- 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
- Engine - Cranking - For 15 s
- 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
- If a condition exists
- Ignition/Vehicle & All vehicle systems - Off
- Install the component: Fuel Return Hose
- Perform the following steps:
- Disconnect the electrical connector: Q17 Fuel Injector - All
- Disconnect the electrical connector: E12 Glow Plug - All - Secure and insulate the connection using electrical tape.
- Remove the component: E12 Glow Plug - One at a time
- Place and hold a clean shop towel over the component: Threaded Hole @ Cylinder Head - Glow Plug
- 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
- Test or replace the component: G18 High Pressure Fuel Pump
Fuel Rail Pressure - Maximum @ At Idle Speed = 120 MPa (17405 PSI)
Perform the following test for all 4 components. - One at a time