Repair Procedures

Fuel Pressure Inspection (Low-Pressure System)

1. 1
   Release the fuel line residual pressure. (Refer to Fuel System - "Release Fuel Line Residual Pressure")

   When the fuel pump relay is removed, a diagnostic trouble code (DTC) is set. Clear the DTC with GDS after completing the "Relieve Fuel Pressure" procedure.

2. 2
   Install the Special Service Tool (SST).

   1. Disconnect the low-pressure fuel feed hose from the low-pressure inlet of the high-pressure fuel pump.

      Some residual pressure may remain even after releasing the residual fuel pressure in the fuel line. Therefore, cover the hose connection with a shop towel to prevent fuel from spilling before disconnecting any fuel connection.

   2. Install the special service tool to measure the fuel pressure between the low-pressure fuel feed hose and the low-pressure inlet of the high-pressure fuel pump (see figure below).

      

3. 3
   Inspect for fuel leaks at the low-pressure fuel feed hose connections, the low-pressure inlet of the high-pressure fuel pump, and the SST components with the ignition ON.
4. 4
   Measure the fuel pressure.

   1. Start the engine and measure the fuel pressure at idle. Fuel pressure: 495 ~ 505 kPa (4.9 ~ 5.1 kgf/cm², 71.8 ~ 73.2 psi)

      If the fuel pressure is out of specification, repair or replace the related part (see the table below).

      Fuel Pressure	Cause	Related Part
      Too low	Clogged fuel filter	Fuel filter
      	Fuel leakage	Fuel Pressure Regulator
      Too high	Fuel pressure regulator stuck	Fuel Pressure Regulator

   2. Stop the engine, then check the fuel pressure gauge reading for changes. Specification: The gauge reading should be held for approximately 5 minutes after the engine is stopped.

      If the gauge reading is not held, repair or replace the related part (see the table below).

      Fuel Pressure (After Engine Stop)	Cause	Related Part
      Fuel pressure drops slowly	Injector leakage	Injector
      Fuel pressure drops immediately	Fuel pump check valve stuck open	Fuel pump

   3. Turn the ignition off.
5. 5
   Release the fuel line residual pressure. (Refer to Fuel System - "Release Fuel Line Residual Pressure")

   When the fuel pump relay is removed, a diagnostic trouble code (DTC) is set. Clear the DTC with GDS after completing the "Relieve Fuel Pressure" procedure.

6. 6
   End of test

   1. Remove the special service tool (SST) from the low-pressure fuel feed hose and the low-pressure inlet of the high-pressure fuel pump.
   2. Connect the low-pressure fuel feed hose to the low-pressure inlet of the high-pressure fuel pump.

Release Fuel Line Residual Pressure

Whenever the high-pressure fuel pump, high-pressure fuel line, fuel feed hose or injector is removed immediately after engine shutdown, injury may be caused by high-pressure fuel spray. Release the residual pressure in the high-pressure fuel line by referring to the "Fuel Residual Pressure Release Procedure" below before removing any high-pressure fuel system components.

Wear protective goggles and fuel-resistant gloves.

1. 1
   Turn the ignition OFF and disconnect the negative battery cable.
2. 2
   Remove the fuel pump relay (A).

   

3. 3
   Disconnect the electrical connector from the high-pressure fuel pump.
4. 4
   Connect the negative battery cable.
5. 5
   Run the engine for approximately 20 seconds to reduce the pressure in the high- or low-pressure line. The engine may stop within the 20-second period. If not, turn the engine off.
6. 6
   Continue with the service or repair. Use a shop towel to cover the opening and collect any spilled fuel when opening the high-pressure system.
7. 7
   Reinstall/reconnect all components in the reverse order of removal. Start the engine, confirm proper operation, and make sure there are no fuel leaks.
8. 8
   After completion, erase the DTCs using the GDS diagnostic tool (the above procedure will set DTCs).