Procedures

High Side Fuel Pressure, Releasing

CAUTION!
The fuel injection system is divided into a high pressure side (maximum approximately 120 bar) and a low pressure side (approximately 6 bar).

Before opening the high pressure side - for example, removing the high pressure pump, fuel rail, fuel injectors, fuel pipes or fuel pressure sensor - the fuel pressure in the high side must be reduced to a residual pressure of approximately 6 bar. The procedure for this is as follows.

- Disconnect the electrical connector from the fuel pressure regulator valve - arrow -.





- Allow the engine to idle approximately 10 seconds.

• When the fuel pressure regulator valve electrical connector is disconnected during idle, the pressure in the high side decreases to approximately 6 bar.

• After the high side pressure has been released, the high side must be opened, otherwise the pressure increases again due to the warming of the fuel.

- Switch off the ignition.

- For safety reasons, disconnect the fuel pump control module electrical connector - arrow - before opening the fuel system.





CAUTION!
Fuel lines are pressurized! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before opening the high side, place a cloth around the connection.

- Place a clean cloth around the connection point and carefully open the high side to release the residual pressure to approximately 6 bar. Leaking fuel must be absorbed.

- To conclude work, check the Engine Control Module (ECM) Diagnostic Trouble Code (DTC) memory, erase all DTC entries which may have occurred from disconnecting the connector. Refer to => [ Engine Control Module DTC Memory, Checking and Erasing ] Engine Control Module DTC Memory, Checking and Erasing.

• If the DTC memory was erased, generate a readiness code. Refer to "Guided Function".