Diagnostic module for tank leaks

In the following countries, a leak diagnosis system is compulsory: USA, Canada, Korea.

The tank leak diagnosis allows the leak-tightness of the tank ventilation system to be determined. Tank leak diagnosis allows a difference to be made between:

• Minor leak greater than 1 mm
• Superfine leak 0.5 mm to 1 mm

The diagnostic module for tank leaks is located on the activated carbon filter. The leak test of the tank ventilation system is carried out after a completed drive cycle after stopping the engine. Here, various processes run in the after-run period of the engine control system.

Fig 1: Identifying Tank Leaks Diagnostic Module And Carbon Canister

Courtesy of BMW OF NORTH AMERICA, INC.

The diagnostic module for tank leaks consists of an electrically driven overpressure pump (leak diagnosis pump) as well as an electromagnetic changeover valve and a reference bore hole. There is also a heating element integrated in the diagnosis module to remove any condensate by heating it up.