Does my diesel have an o2 sensor?

[martincloud9]

My leon TDI has been running rich for a while due to a EGR issue. That is now fixed, but is not back up to it's best MPG. I'm wondering if something has got sooted up because of it.

I've found mixed messages on this. Does my Seat Leon Cupra TDI 150bhp PD ARL have an o2 sensor?
If not, does it have anything of the sorts?
Otherwise, how does it test the outcome of the exhaust gases? I'm sure guessing/assuming wouldn't be the best approach.

Thanks

 

[Bogwoppit]

Nope it doesn't have an oxygen sensor.
If MPG has gone down it could be a fauly MAF, an air leak, blocked inlet manifold/EGR etc...

 

[martincloud9]

Hmmm, just cleaned the EGR and inlet. Fuel lines checked and seals replaced. Checked the timing, had the injector seals replaced. Replaced the turbo and MAF sensor.

http://www.seatcupra.net/forums/showthread.php?t=209186

It just seems a little strange to have a system where the outcome isn't checked, just assumed.

 

[martincloud9]

So how is the fuel mixture checked?
What does the car do to check that the a/f ratio is correct?
If there is no o2 sensor, it must check the exhaust gases another way.