I recently gave my 1990 190e a routine service changed the oil, plugs and wires. After i was done i started the car back up and the check engine light came on. The led light blinked 11 times which i believe is an air injection issue. I can't see any visible issues but i do a hear slow clicking noise coming from somewhere around the air cleaner.Any ideas at what the issue is?
Thanks,
Graham

Welcome,
Start by looking at the vacuum lines that go to the switchover valve & the diverter valve.

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