Mercedes w203 w209 w211 w230 Fuel gas tank Cap OEM Brand new, Genuine Mercedes-Benz Gas Cap for your fuel tank. Gas caps with poor seals will trigger Check Engine light, due to emissions of gas fumes that are closely monitored. Mercedes part# 221 470 06 05, supersedes# 168 470 02 05 Comes with tether to prevent loss, but some owners cut it off so that the cap isn't scratching the body while filling up.