sgore

Hi all car is 2002 w203 c32 amg the secondary air pump comes on as normal when car is cold stays on for approx 20 seconds But every now and again the pump comes on when engine is hot which puts the cel on, as i understand the pump it should only come on when cold for 20 seconds any ideas to why the pump is coming on when engine is hot ?
Car has had secondary cat delete would this cause it ? Thanks.

Plutoe

There are five electormechanical components in that system----what was and or is the fault code number??

kbob999

FYI - My air pump comes on when coming to a red light stop with engine idling. It also comes on when cold. Seems normal operation to me.
I suspect your CAT delete has something to do with it. Check codes and go from there.

Morphh

if don't have code p0401 or p0410 ur fine for

Pansu

Relay is common failure. Secondary cat dont have anything to do this.