Hello,
My 05 Spec-B has a P0420 code since several weeks.
I tried to datalog with a tactrix cable, hoping to see where the problem comes from, between the front O2 sensors, the cat and the rear O2 sensors, or from somewhere else...
The A/F sensors #1 and #2 are always equal, richens at high load and RPM, stable at 14.7 in cruise. (I think these are the front O2 sensors, could you please confirm?)
The other sensors are called front sensor #1 and #2 in Romraider datalogger but I suspect these are the rear ones, having a value between 0V and 1V, they oscillate nearly at the same frequency and amplitude in cruise.
I also logged A/F correction and learning, but I cannot say from these values what is going wrong.
Here are examples of log:
Are there some other parameters which O should look at?
When I reset the ECU, the Error code will come again sometimes after 10 minutes, sometimes after 4 or 5 days. It depends. I never managed to log the moment where the code appears. Should I try to reset the error and log until the CEL lights?
Or would you have other advices?