Fuel Pump: Service Precautions

Safety Precautions


The fuel pressure in the high pressure pipe can be up to 120 bar! Follow the safety precautions when releasing the high side pressure.

• Reducing the high side pressure. Refer to => [ High Side Pressure, Reducing ] High Side Pressure, Reducing.

• The fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before disconnecting the connection, wrap a cloth around the connection. Then, disconnect the hose connection carefully to release the pressure.

For safety reasons, turn off the current to the fuel pump before opening the fuel system. Otherwise the fuel pump will activated when the driver door is opened. Use one of the following ways to turn off the current:

• Battery, disconnecting

or

• Remove the fuse for the fuel pump control module (J538)

or

• Disconnect the connector from the fuel delivery unit flange or from the fuel pump control module.


When doing any repair work, especially in the engine compartment, pay attention to the following due to clearance issues:

• Route all lines and wires in their original locations.

• Ensure sufficient clearance to all moving or hot components.

To reduce the risk of personal injury and/or damage to the fuel injection and ignition system, always observe the following:

• Do not touch or disconnect the ignition coils with power output stages when the engine is running or turning at starting RPM.

• The ignition must be turned off before connecting or disconnecting injection and ignition system wiring or tester cables.

Always observe the following when removing and installing the fuel level sensor or the fuel pump from a full or partially filled fuel tank.

• Before starting work, place the extracting hose from an exhaust extractor that is switched on near the fuel tank assembly opening. This will extract the fuel vapors. If no exhaust extraction system is available, a radial fan (as long as motor is not in air flow) with a displacement greater than 15 m3/h can be used.

• Prevent fuel from contacting skin! Wear fuel-resistant gloves!

If special testing equipment is required during road test, note the following:

• Testing and measuring instruments must be secured on the rear seat and operated by a second person from that location.

• If the vehicle is involved in a collision while testing and measuring equipment is operated from the front passenger seat, the person sitting in that seat could be seriously injured when the airbag deploys.