Releasing Fuel Pressure In High Pressure Area

Fuel pressure in high pressure area, releasing

CAUTION! The fuel injection system is divided into a high pressure section (maximum approx. 120 bar) and a low pressure system (approx. 6 bar).
Before opening high pressure area - e.g. removing high pressure pump, fuel rail, fuel injectors, fuel pipes or Fuel Pressure Sensor G247 - fuel pressure in high pressure area must be reduced to a residual pressure of approx. 6 bar. The procedure for this is as follows.





Remove electrical connector from Fuel Pressure Regulator Valve N276 -arrow-.
Allow engine to idle approx. 10 seconds.

Note: When the Fuel Pressure Regulator Valve N276 electrical connector is disconnected during idle, pressure in high pressure area decreases to approx. 6 bar.
After high pressure has been released, high pressure system must be opened immediately. Otherwise, the pressure can increase again due to the warming of the fuel.

Switch off ignition.

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

Place a clean cloth around connection point and carefully open to release residual pressure of approx. 6 bar. Escaping fuel must be absorbed.
To conclude work, check DTC memory of Engine Control Module (ECM), erase all DTC entries which may have occurred from removing the connector.

Note: If DTC memory was erased, generate readiness code "Guided Function".