Does any no how to find out if the lamba sensor isn't reading properly? I've got vagcom but don't understand the values

Thanks

you must see a squarewave using the VCDS scope.Check here the green wave....that's at idle with engine warmed.

Then if you accelerate gently the squarewave must get smaller and smaller in scale,then release the pedal and you should see a "pause" of 2-3 seconds.

 

http://www.youtube.com/watch?v=REh0tH6IQ_0

 

 

This is roughly how you can tell if the O2 sensor works

Thanks mate il give it ago, is that block 7?

yes

Can you read a long and short term fuel trim figure in engine block 32 ??

 

 

If so your lambda is working, whether its reading correctly is another matter !!

Can you read a long and short term fuel trim figure in engine block 32 ??

If so your lambda is working, whether its reading correctly is another matter !!

Hi mate, I'm not to glued up on fuel trims, how would I determin bad fueling?

you must see a squarewave using the VCDS scope.Check here the green wave....that's at idle with engine warmed.

Then if you accelerate gently the squarewave must get smaller and smaller in scale,then release the pedal and you should see a "pause" of 2-3 seconds.

 

http://www.youtube.com/watch?v=REh0tH6IQ_0

 

 

This is roughly how you can tell if the O2 sensor works

That`s for AGU engine with narrowband lambda not for AUQ/AUM engine with precat wideband lambda sonda B1S1 and postcat sonda B1S2

Hi mate, I'm not to glued up on fuel trims, how would I determin bad fueling?

If it`s more than -10%+10% in both block

That`s for AGU engine with narrowband lambda not for AUQ/AUM engine with precat wideband lambda sonda B1S1 and postcat sonda B1S2

Doesn't matter is if narrowband or wideband,or 4.2 V8 lambda square wave is the same on all engines.VCDS scope will show the same on any VAG engine

Only the group on VCDS will be different

Hi mate, I'm not to glued up on fuel trims, how would I determin bad fueling?

 

 

If you can see anything other than zero in the boxes that means lambda is working, like I say whether its actually reading right is another matter 

 

Heres a little light reading on the subject of fuel trims, I suggest your read it a few times lol