old96A4

Can some tell me what the procedure would be to test for a bad cat or to compare the bank 1 - 1 and 2 O2 sensors. Can't seem to figure it out which blocks to use..
Should I be driving and capture data?

Prospeeder

Do you get a cat code? if so thats whats wrong. Theres really nothiing else going to cause that code. It moniters cat performance for days before it will decide the turn the light on. if there is no engine light, its working fine.

bearthebruce

I'm guessing this is on your A6 - right?

The o2 sensors are usually found in measuring value blocks 030 through 039. Usually, you want to test with a scope - not with the scan tool - although the scan may give a hint. Basically, the rear sensor should read much less than the front sensor - indicating that the CAT is doing it's job.

Take a look at this article for more help: http://www.autoshop101.com/forms/h64.pdf In particular, go to the last page and read how the sensor will function and how you can tell with a scope if you have a good Cat.

Thank Toyota for the article.

firestarter_phil

I've got a similar query which I'm interested in people's thoughts on.
I have installed after market cats onto by D2 A8 (due to cost) and they have passed the legal tests in the UK for the past 4 years. However my engine management light is on, with the message that both cat banks are below threshold.

I'm OK with this, but wondered if there is a way with VAG COM to adjust what the threshold is and therefore prevent the engine management light coming on. The reason for this is that the law is changing and an engine management light being on is deemed a failire in the UK.

Any thoughts on this people?

Phil