Sam1977

Just recently installed a Carbonio Air Box (+filters it comes with) and all was good for a few weeks.

Now all of a sudden I'm getting the Engine light come on. Took it to dealer yesterday who reset the error (which was Oxygen sensor bank 1 has electrical fault)

Would this have anything to do with the Airbox, i.e. too much air messing with fuel/oxygen level and throwing off the error)

Also had a tune pre installing air box, dont know if l have to retune?

Thanks in advance

Merc63

Oxygen sensors are in the exhaust. They don't last forever.

Sam1977

car only has 28,000Km's on it

Yep know they are in the exhaust and thought they measured the air/fuel mixture being pumped out the back for pollution purposes

Higgs Boson

oxygen sensors sense oxygen, FYI.

Merc63

Yep ^^ they measure oxygen levels in the exhaust. No oxygen = stoichiometric.

Monitoring the cats is the function of the secondary O2s.

The primary O2s control the AFR via closed loop feed back.

Sam1977

so if i take it to Mercedes they shouldn't turn around and say it's b/c of the air box/filter addition?

Merc63

Dealer will always blame after market parts. Lots of the techs are useless, the odd one will actually try to fix it.

Sam1977

It's booked, lets see how we go

Merc63

Jack your car up and switch the secondary O2s (after the cats) to the opposite sides. If the code switches sides, get a new sensor.

Unless you have warranty, then dealer u go.

Sam1977

Exact same advice I got from my tuner

Merc63

Youre tuner is a smart man