1998 e320 4-matic check engine/codes
 

I just purchased a '98 e320 runs fine but check engine electronics was displayed. Took it to Advance auto and the codes are.
p0410 secondary air injection syst. malf.
p0400 EGR flow malfunction
p0130 o2 sensor circuit malf.(bank 1 sensor 1)

The car seems to run ok but I would like to know what could cause this. I had them clear the codes to see if they will reappear.

All are common codes!

The P0 130 "could" cause the P0 410. So starting with a new passenger (right) front sensor would be my starting point.

The P0 400 EGR code is most likely from a clogged EGR tube. They can be cleaned.

OF course a scanner with activation featured would help!

1998 e320 codes/egr tube
 

Thanks for the info. New O2 sensor on the way. Where is the egr tube located? Thanks for the help.