[Solved] Audi A4 B6 1.6 - P0420 - voltage of the probe with a faulty catalyst

Hi, recently my "check" light came on. I connected it to the computer and checked what it was and it showed me error P0420 - performance of the catalytic system below the required value. So I read on the internet that the easiest way to diagnose a catalytic converter fault is to check the voltage of the probe behind the catalytic converter. Unfortunately, I do not know this for anything in the world and I decided to write here and ask experts in this field if the cat is already suitable for replacement after the indications that the program shows. So - what do you think? If the catalyst is on the finish (I think), will the use of a probe emulator help?
Thanks in advance for any help.

Yellow graph is B1S1, black B1S2 I presume?
Everything indicates that the cat is dead. Burnt out or just old.

If both graphs coincide, it means that the angle does not fulfill its function. E.g. because it's cold or out of order. Do the cold test again and you'll see what I mean.

Over time, as the cat starts to heat up, the first probe B1S1 works lean - rich (0V to about 1V), the second probe B1S2 starts to run rich (0.5V to 1V).

It's best to do an exhaust gas analysis. If CO is greater than 0.5%, the cat is faulty.

Replace the catalyst or there are any emulators or sleeves for the second probe.

fuelinyourblood wrote:

Yellow graph is B1S1, black B1S2 I presume?
Everything indicates that the cat is dead. Burnt out or just old.

If both graphs coincide, it means that the angle does not fulfill its function. E.g. because it's cold or out of order. Do the cold test again and you'll see what I mean.

Over time, as the cat starts to heat up, the first probe B1S1 works - rich (0V to about 1V), the second probe B1S2 starts to run rich (0.5V to 1V).

It's best to do an exhaust gas analysis. If CO is greater than 0.5%, the cat is faulty.

Replace the catalyst or there are any emulators or sleeves for the second probe.

That's the answer I was looking for - thanks a lot, I'll rather buy this emulator to have the problem temporarily solved. The catalyst is too expensive for now.