I can check whether the ebay VAGcom will work or not once I get back to the house.

Anyways, if you can read measuring blocks from 34, 35, & 36 you can test o2 sensors. For catalytic converter tests, you need 46 and 47. Basically start with the measuring block 34. Your car should be at normal operating temperature, start the car, step on the brake and keep the RPM somewhere between 1400 and 2000. Test will turn itself on once the car thinks it is ready. Repeat 35 & 36, and do 46 and 47.

34 - Bank 1 before Cat O2 sensor aging test
35 - Bank 2 before Cat O2 sensor aging test
36 - Bank 1 and 2 after Cat O2 sensors readiness
46 - Bank 1 Cat Converter conversion test
47 - Bank 2 Cat Converter conversion test

FYI, 46 and 47 will initialize only after completing 34 and 35. At the end of each test it will tell you whether the component is ok or not ok.

 

the ebay version only goes to #3, but here were the results for the engine
2 faults found
16795 - secondary air injection system: incorrect flow detected
P0411 - 35-10 --- intermittent
16806 - Shareware version. To detect all DTCs
P0422 - 35-00 Please register/activate

That doesnt tell me anything about which O2 sensor is bad does it?

I know for sure my cats have gone bad, so this is alot of money already, and I don't want to spend about $200 at the dealer, just to know which o2 sensor has gone bad

 

P0411 usually (but not always) is related to a vacuum leak. Check the vacuum lines at the rear of the motor going to combi valves.

As for P0422, it is your bank 1 main catalytic converter. I believe you knew about that one already. So it maybe worth your money to buy a license for VAGcom. It is $99 and can be used with the ebay cable, because that is what I have. Then you can check your o2 sensor.

 

they told me at carx, that both cats are bad, why is the car only reporting bank1?

Also when we talk about o2 sensors, are we talking about
this,
http://www2.partstrain.com/includes/...Ugd2FycmFudHku

Or this,
http://www2.partstrain.com/includes/...IxOTA2MjY1QUgi

Because one is $20, and one is $115???????

 

I would ask them how they are sure that the both catalytic converters are bad. If they ran test procedures as noted above, ask them to show you the result. Otherwise, I would just replace the side that is actually giving you the code.

As for the O2 sensor, there a 4 of them in our cars. 1 each, before the main converter, on both sides, and 1 each, after the main converter, on both sides.

But let me ask you a question... Why do you think your O2 sensor needs replacing?

 

well when I first got the p0422 code, most people have been telling me that it's most likely that O2 sensors, and not the cats. At this point in time, which was about 3 month ago, there was nothing wrong with the cat. I ignored the code about 3 times, then the cat stated rattling. So I'm assuming that since there was nothing wrong with the cat at first, then it must've been the O2 sensors, which led to the cat malfunction later on.

Now I don't want to get the new cats, then if the O2 sensors really are bad, then the cats will go bad again.

The other thing is, to know if the O2 sensors are bad I'll pay at least the $99 vag com license, which is why I was asking what's the difference between the $20 O2 sensor and the other. If the $20 one is fine, then I might as well get 4 and pay $80.

I suck at this though, and I have no money, and I'm just trying to get by this car until I graduate from college in a couple of years.

 

If your cat is rattling, it has been bad for a long time. It doesn't go bad in a single day, even with bad o2 sensors, it would have taken months if not years for the coverters to go bad, not days... And considering you want to save money, don't replace anything that you are not sure about. My personal rule of auto repair is that fix only thing that you know for sure is broken, unless it is preventative maintenance.

Anyways, proper o2 sensors are expansive. Think $150, not $20. There are many documented cases where cheap o2 sensors did not work at all. Personally, I wouldn't trust $20 O2 sensor. Get prewired Bosch sensors from the dealer, or ECS or other reputable places, not ebay. If you want to save a couple of bucks by getting the universal sensors (which you need to cut wires and connect), get Bosch ones, not miscellaneous off brand name. You are still looking at about $100 each.

If you live in a state where smog check is required, you need to fix it the right way. If you know for sure that your converters are bad, then I would replace the converters, then check the O2 sensors to see if they are working properly. Then replace if needed.

I know it hurts to drive an Audi, but sometimes, you just have to pay to play.

 

O2 sensors for all the Audis apparently are heated.
The models from 85 to 95 have three-wires sensors.
For the models 96-on they have four (4) wires. Some models from 96 to 2000 have the front sensors with 3 wires, while the two back ones are with 4 wires.
Someone with more Audi experience can shed more light on the subject for you.

However, you surely don't want to waste $ 20 for a sensor that would not work for your car.
Do some tutoring; work some extra shifts on weekends; lay off the trips to the bars for a while; escort some old rich hags; or just beg your parents for money to purchase the O2 sensors, but you definitely don't want to spend the money on 2-wired sensors that would not work on your car.

 

o2 sensors arent the issue here. Catalyst efficency code means the cat is bad. Replace your bank 1 cat and your problem should be solved. If you have no codes for the o2 sensor then it is operating within its limits.

 

Ok so not to rain on your parade or anything but when you say this ^^

Which one is the bank 1 cat? I have searched day and night for threads that show which one and how to change it..