Fuel System

Fuel System

Note the following when working on the fuel system:

• For safety reasons, if the battery is not disconnected, the Fuel Pump (FP) control module (J538) fuse must be removed before opening fuel system. Otherwise, the fuel pump will be activated by the driver door contact switch.

• Fuel system is under pressure! Fuel pressure must be reduced to a residual pressure before opening high pressure area of injection system. Refer to engine code CAEB => [ Reducing Pressure for Vehicles with Engine Code CAEB ] Reducing Pressure For Vehicles With Engine Code CAEBor engine code CHJA => [ Reducing Pressure on Vehicles with Engine Code CHJA ] Reducing Pressure on Vehicles With Engine Code CHJA.

• After reducing high pressure, connection should be opened immediately. To do this, place a cloth around the connection to reduce residual pressure (approximately 7 bar).

• By removing the fuse - in the fuse panel in the instrument panel on the driver side -, the voltage supply to terminal 30 for the FP control module is interrupted.

Even a little contamination can lead to faults. When working on the fuel supply and on the fuel injection system, observe the following guidelines for a clean working environment:

• Before loosening, connections and surrounding areas must be cleaned thoroughly with engine or brake cleaner, and then the cleaned area must be dried completely.

• Plug open lines and connections immediately with appropriate protective caps.

• Place removed parts on a clean surface and cover them. Use lint-free cloths.

• Only install clean components: Remove the replacement parts from their packaging just prior to installing them. Do not use parts that have been stored unpacked (for example in tool boxes etc.).

• When the system is open: Do not work with compressed air. Do not move vehicle unless absolutely necessary.

• Protect the disconnected connectors from dirt and moisture and only connect when they are dry.