Note
- The fuel piping between the fuel tank and the fuel supply pump is slightly vacuumed when the engine is running. Therefore, if the piping is not connected securely, air can get inside. If the engine speed or the engine load increases while air is in the fuel system, fluctuation in the fuel rail pressure occurs.
- If the vehicle runs out of fuel, air may be entered in the fuel system. When there is air in the fuel piping, the smooth flow of fuel into the fuel supply pump is interrupted and this DTC may be set. Bleed air from the fuel piping after refilling.
1. Engine control system check
Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".
2. Prioritized DTC check
1) Connect the scan tool.
2) Turn OFF the ignition switch for 30 seconds or more.
3) Crank the engine for 15 seconds.
4) Observe the DTC information with a scan tool. Is a DTC set?
Yes
Go to the applicable DTC diagnosis.
No
=>Go to Injector operation check.
3. Injector operation check
1) Perform the Cylinder Balance with a scan tool.
2) Command each injector ON/OFF while checking the operation sound of the solenoid. Does the solenoid make any operation sound with the execution of each command?
Yes
=>Go to Fuel amount inspection.
No
Replace the injector if a malfunction is found.
Note
- If an injector has been replaced, be sure to set the Injector ID Code on the ECM.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector installation".
4. Fuel amount inspection
1) Inspect the fuel amount. Is the fuel amount adequate?
Yes
=>Go to Fuel quality inspection.
No
Refill with the fuel.
=>Go to Fuel quality inspection.
5. Fuel quality inspection
1) Take a fuel sample from the fuel tank and inspect whether the fuel quality is good. Is the result normal?
Yes
=>Go to Fuel leakage inspection in the component..
No
Change the fuel.
6. Fuel leakage inspection in the component.
1) Inspect for a fuel leakage at the high-pressure side components between the fuel supply pump and the injector for the following. Is the result normal?
- Fuel supply pump
- Fuel rail
- Pressure limiter
- FRP sensor
- The fuel pipe between the fuel supply pump and the fuel rail
- The fuel pipe between the fuel rail and the injector.
- Sleeve nut of the fuel pipe
Note
- Check for fuel leakage from the high pressure piping inlet to the bottom of the cylinder head cover. If a fuel leakage exists, the engine oil level will rise. Inspect the engine oil for fuel contamination.
- Remove and inspect the high-pressure pipe joints connected to the injectors for fuel leakage from the sleeve nuts. When foreign material is attached, replace the injector and the high pressure pipe.
Yes
=>Go to Fuel leakage inspection.
No
Repair as necessary.
7. Fuel leakage inspection
1) Operate the priming pump until the force required for pressing increases.
2) If the force for pressing the priming pump does not become heavy, inspect for fuel leakage between the priming pump and the fuel supply pump. Is the result normal?
Note
- When a leak exists in the fuel system between the priming pump and fuel supply pump, the pushing weight of the priming pump does not get heavy.
3) Inspect that the fuel piping between the fuel tank and the fuel supply pump is properly connected, there are no cuts or cracks in the fuel hoses, and proper clamps are used. Is the result normal?
Note
- The fuel piping between the fuel tank and the fuel supply pump is slightly vacuumed when the engine is running. Therefore, if the piping is not connected securely, air can get inside. If the engine speed or the engine load increases while air is in the fuel system, fluctuation in the fuel rail pressure occurs, and this DTC may be set.
4) Are all of the results normal?
Yes
=>Go to Fuel pressure verification.
No
Repair as necessary.
8. Fuel pressure verification
1) Bleed the air from the fuel piping as necessary.
2) Start and idle the engine. If the engine does not start, continue cranking.
3) Observe the Fuel Rail Pressure (FRP) parameter and Desired Fuel Rail Pressure (FRP) parameter on the scan tool. When idling or cranking the engine, is the difference between the Fuel Rail Pressure (FRP) parameter and the Desired Fuel Rail Pressure (FRP) parameter within the specified range?
Value: -5 to 5 MPa { -725 to 725 psi }
Yes
The system is normal.
No
=>Go to Suction side fuel piping inspection.
9. Suction side fuel piping inspection
1) Turn OFF the ignition switch.
2) Disconnect the fuel feed hose from the fuel supply pump.
Note
- Use a pan to collect the fuel that has leaked from the disconnected fuel feed hose.
3) Connect the vacuum pump to the fuel feed hose.
Note
- The vacuum pump must be cleaned before connecting to the fuel piping. The fuel supply pump may be damaged due to the foreign material that has intruded into the connection hose.
SST: 5-8840-0279-0 - vacuum pump
4) Operate the vacuum pump and inspect for fuel smooth flow. Is the result normal?
Caution
- Take care that no fuel enters the vacuum pump.
Note
- If there is a leakage or restriction in the suction side, the smooth flow of fuel may be interrupted due to fuel leakage, fuel filter element clogging, twisting or collapsing of the fuel hose or pipe, etc. Also, foreign material in the fuel tank may enter the fuel piping.
Yes
=>Go to Fuel supply pump suction check.
No
Repair the fuel piping between the fuel tank and the fuel supply pump.
10. Fuel supply pump suction check
1) Connect the fuel feed hose to the fuel supply pump.
2) Disconnect all the injector harness connectors (E12, E13, E14, and E15) in order to disable the fuel injection.
Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
3) Disconnect the fuel feed hose from the fuel tank.
Note
- Use a pan to collect the fuel that has leaked from the disconnected fuel feed hose.
4) Connect the vacuum pump to the fuel feed hose. Make sure that the connection between the vacuum pump and the fuel feed hose is secured.
SST: 5-8840-0279-0 - vacuum pump
Note
- The vacuum pump must be cleaned before connecting to the fuel piping.
5) Crank 3 times while monitoring the vacuum pump gauge. Can a vacuum of the specified value be drawn?
Caution
- Cranking should be performed within 5 seconds at a time, and should not exceed 15 seconds in total.
Value: -8.5 kPa { 2.5 inHg }
Caution
- If it is likely that the vacuum will show the specified value or more, stop cranking immediately.
Yes
=>Go to Pressure limiter inspection.
No
=>Go to Inspection for air bubble intrusion.
11. Inspection for air bubble intrusion
1) Replace the fuel hose between the fuel supply pump and the fuel filter with a clear hose.
2) Bleed the air from the fuel piping.
3) Start the engine.
4) Allow the engine to idle for at least 1 minute.
5) Inspect the fuel in the clear hose for air bubble intrusion. Is the result normal?
6) Inspect that the fuel piping between the fuel tank and the fuel supply pump is properly connected, there are no cuts or cracks in the fuel hoses, and proper clamps are used. Is the result normal?
7) Are all of the results normal?
Yes
Replace the fuel supply pump and the fuel filter element.
Note
- The fuel supply pump must be timed with the engine, and the ECM requires learning.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) fuel supply pump removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) fuel supply pump installation".
Caution
- If the fuel supply pump is replaced, replace the fuel filter element at the same time.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) fuel filter element removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) fuel filter element installation".
No
Repair the fuel piping between the fuel tank and the fuel supply pump.
12. Pressure limiter inspection
1) Turn OFF the ignition switch.
2) Check whether all the injector harness connectors (E12, E13, E14, and E15) are disconnected.
Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).
3) Remove the rubber hose from the injector leak-off pipe.
4) Remove the leak-off pipe assembly from the fuel feed pipe and pressure limiter.
Note
- Use a pan to collect the fuel that has leaked from the disconnected fuel hose.
5) Crank the engine.
6) Inspect for fuel leakage from the pressure limiter. Is the result normal?
Caution
- If a malfunction is found in the pressure limiter, wear protective goggles as the fuel may spatter.
Yes
=>Go to Injector leak-off pipe inspection.
No
Replace the pressure limiter.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) pressure limiter removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) pressure limiter installation".
13. Injector leak-off pipe inspection
1) Crank the engine.
2) Inspect for fuel leakage from the injector leak-off pipe. Is the result normal?
Caution
- If a malfunction is found in the injector, wear protective goggles as the fuel may spatter.
Yes
=>Go to Inspection for leakage into the combustion chamber.
No
Replace the injector in which fuel leakage was found and inspect the engine for any damage or poor engine compression.
Note
- If an injector has been replaced, be sure to set the Injector ID Code on the ECM.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector installation".
14. Inspection for leakage into the combustion chamber
1) Remove the glow plugs from the cylinder head.
Refer to "1.Engine 1J.Electrical(RZ4E-TC) glow plug removal".
2) Inspect for fuel leakage into the combustion chamber. Is the result normal?
Yes
No
Replace the injector in which fuel leakage was found and inspect the engine for any damage or poor engine compression.
Note
- If an injector has been replaced, be sure to set the Injector ID Code on the ECM.
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector removal".
Refer to "1.Engine 1C.Fuel System(RZ4E-TC) injector installation".
15. Repair verification
1) Reconnect all of the disconnected harness connectors and components.
2) Bleed the air from the fuel piping as necessary.
3) Start and idle the engine. If the engine does not start, continue cranking.
4) Observe the Fuel Rail Pressure (FRP) parameter and Desired Fuel Rail Pressure (FRP) parameter on the scan tool. When idling or cranking the engine, is the difference between the Fuel Rail Pressure (FRP) parameter and the Desired Fuel Rail Pressure (FRP) parameter within the specified range?
Value: -5 to 5 MPa { -725 to 725 psi }
Yes
The system is normal.
No