ReneDK

I have a 2006 Lexus IS250 with 85.000 miles on it.

3 weeks ago I got the P0420 error code, I deleted it and now it's back. No big surprise, really .

After watching the live data, it looks like Sensor 1 Bank 1 and Sensor 1 Bank 2 looks almost identical.

Therefore I think the problem must be the Sensor 2 or the TWC.

Could you take a look at these screenshots and tell me what you think?

http://www.daekberegner.dk/autel.jpg

Picture 1 and 2 shows Sensor 2 (bank 1 and bank 2)

They definitely does not look the same.

It looks like sensor 2 bank 1 is moving up and Down much faster than the sensor 2 bank 2?

Catalyst Monitor Bank 1 (Picture 3) says FAIL
Catalyst Monitor Bank 2 (Picture 4) says OK

Looking forward to hear from you.

Regards from Denmark

panda08

iTrader: (1)

test the resistance of the bank 1 sensor 2.

ReneDK

Should I measure the resistance when the sensor is unplugged. How many ohm should one expect for a fully working sensor?

ReneDK

After having a look underneath the car, I found a tiny hole in the exhaust pipe 1 inch after the downstream 02-sensor.

I have repaired the hole and my o2-sensor readings are now OK and the P0420 does not show anymore.