Fuel Tank Leak Detection Function
- The Fuel Tank Leak Detection Module -GX36- -1- is used to check the tank ventilation system -3- for the smallest leaks (less than 0.508 mm diameter) and small leaks (less than 1.016 mm diameter). It consist of an electric air pump (Leak Detection Pump - V144-), a change-over valve (Fuel Tank Leak Detection Valve - N732-), and a reference leak with a 0.508 mm diameter, which is used as a reference measurement.
- The tank system is checked for leaks by comparing the actual current draw for the air pump with the current draw that is present when the system is operating with a standardized reference leak.
- For the reference measurement, the air pump is switched on briefly while the change-over valve is closed and the current draw of the air pump motor is measured while fresh air is pumped from the air filter -2- through the reference leak.
- Before diagnosis starts, the Fuel Tank Leak Detection Module - GX36- is heated for a certain amount of time by the Fuel Tank Leak Detection Heater - Z186- to avoid moisture from condensation.