I have CEL codes P0411 and P0135 and I found out that there is no power to the air pump.Does anyone know whether air pump is on all the time or there is some controll unit that switches air pump on and off? Where is air pump relay and/or fuse on 1996 E320?

Fuse & relay are both part of the "K40" relay module in the computer box at the RR of the engine compartment.

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