Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
System description
In order to prevent fuel vapors from entering the atmosphere, an EVAP canister is connected to the tank ventilation line.
Fuel vapors are collected in the EVAP canister. As the EVAP canister can only accommodate a certain amount of fuel vapors, these must be taken in and combusted during driving.
For this to occur, the EVAP canister purge valve (1) opens. Due to the vacuum predominating in the intake manifold, air is sucked up via the purge air line (3) through the EVAP canister. The air sucked up in this way draws the collected fuel vapors with it.
American law requires the tank ventilation system to be checked for leaks. For this purpose, the tank pressure sensor (5) and shutoff valve (6) are required.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.