Lambda Sensor?

[Vasily87]

Hi got an mot done on the good ladies car and the emissions are high so was looking at changing the lambda. However i understand there are two on the ibiza, any way of daignosing which to change or is there one that fails more than the other? thanks, also i have vcds lite if it can help me check!

[RUM4MO]

As you have VCDS - lite, use it to find out if there are any logged faults - though you would have said if there were, which leaves maybe just an inefficient cat, but the car should have warned you about that. Sounds like you will need to dig deep to get VCDS to help you. Maybe start by checking the plugs and air filter just to make sure the car is fit to run cleanly.

Edit, on re-reading your posting, it sounds like the car passed but some of the readings were higher than you expected them to be, if that is so, then replacing the B1 S1 Lambda sensor, as its the control sensor, doing that should prevent any further poisoning of the cat - the B1 S2 Lambda sensor is just a monitor to check that the exhaust output from the cat is okay. Which engine is fitted to that car?

One thing about VCDS or any other scan tool, its a bit like a socket set, if you don't already know how to do the work then it will not be able to help you - though it should do no harm just to read fields - I've always thought that with a good tool like VCDS, there should be someone out there that could compile a very large list of tasks and how to carry them out. The VCDS website has just a few common application guides - but not exhaustive enough, so there is still some work that someone could do there for some extra cash!