EVAP System Function Test
WARNING: This page is about a different car, the 2024 Audi S6 and 2024 Audi A6 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
Vehicles with High-Voltage System
- In electric driving mode, the Tank Switch-Off Valve -N288- -2- closes the breather line -4- to the EVAP canister -3-, so that it is not overfilled with fuel vapor, for example, when driving electrically for days on end.
- Because the pressure in the fuel tank -1- increases due to temperature effects when the breather line is closed, the Fuel Tank Pressure and Temperature Sensor -GX49- -5- monitors the tank internal pressure and via the engine control module causes the Tank Switch-Off Valve -N288- to open at a residual pressure of 0.3 bar (4.35 psi). Additionally, the valve opens when the fuel filler door release button is pressed, so that no fuel can squirt out of the filler neck when opening the cap to fuel.