Hi! I'm new to the forum, even though I've read multiple posts here before.
I bought my T23 (VVT-i) a year ago with a P0420 error code. The previous owner said the catalytic was replaced and the car passed the emissions inspection here in Spain without any problems. I trust in him because he is a good friend's friend. Also, the motor had the engine rebuilt around 10000km ago.
I got myself an OBDII reader and saw that o2 sensor 1 worked perfectly, but sensor 2 was erratic. Sometimes it was good (no movement) but then it started to oscillate at the same rate as sensor 1, then back to no movement. It doesn't vary with RPM. It's the seme at idle and at 2500rpm.
When I clear the ECU, it takes a long time for the error to re-appear, even though sensor 2 is acting weird.
I've thought of cleaning the cat with cleaner just to be sure and maybe put a sensor defouler? I really don't want to "trick" it but I'm running out of ideas, so if any wise t23 owner or mechanic could lend me a hand it would be great
Thank you for your help!
