Monitoring Function

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2010 BMW M6, 2010 BMW M5, 2009 BMW M6, 2009 BMW M5, and 2008 BMW M6. However, it is still accessible from the selected car via links, so may be relevant.

By means of a D iagnostic M odule_T ank L eakage (DM_TL), an electrically actuated pump located at the atmospheric connection of the evaporative canister, a pressure test of the evaporative system is performed in the following order:

During the reference leak measurement, the electrically actuated pump delivers through the reference restriction. The engine-management system measures the pump's electrical current consumption in this phase.

Fig 1: Fuel System Diagram - During Reference Leak Measurement
Courtesy of BMW OF NORTH AMERICA, INC.
During the Leak Measurement, the electrically actuated pump delivers through the charcoal canister into the fuel-tank system. The pressure in the evaporative system may be up to 25 hPa depending on the fuel level in the tank. The engine-management system measures the pump's electrical current consumption. A comparison of the currents of the reference leak measurement and the leak measurement is an indication of the leakage in the tank.

Fig 2: Fuel System Diagram - During Leak Measurement
Courtesy of BMW OF NORTH AMERICA, INC.
After the test the remaining pressure in the evaporative system is bled off through the charcoal canister by switching off the pump and solenoid valve.

Fig 3: Fuel System Diagram - Switching Off Pump And Solenoid Valve
Courtesy of BMW OF NORTH AMERICA, INC.