To troubleshoot the vapor canister purge solenoid on a Mercedes-Benz, scan for EVAP codes (P0440 to P0446), then bench test the valve: it should be closed with no power, hold vacuum from a hand pump, and click open the moment you apply battery voltage. If it leaks vacuum or does not click, replace it. The purge valve …

To fix an EVAP canister problem, read the trouble code first, then work from the cheap parts to the expensive one: tighten or replace the gas cap, look for cracked hoses, and test the purge valve with a hand vacuum pump. If the charcoal canister is only clogged, you can blow it clear with 50 psi of compressed air. If …