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International Automotive Technicians Network
Re: 97 Mercedes e420 -check engine light on
Posted to Technical Discussion Forum on 10/6/2003

HI Paul

Just to expand on what Eric said. The ME (Motor Electronics) controller needs to see no more then 40mv in less then 30 seconds from the O2 sensor or it thinks the AIR system has malfunctioned.

To test this is quick and simple. Turn on the air pump ... Login to read more.