Log file help.

[aaronr]

What guys think. Do think my long fuel trims look o.k. I'm also getting the p0420 code and whanted know if there is anyway to tell if the cat bad by logging the pre and post 02 sensor like show in my log file.
Thanks.

9014

[joecar]

Delete MAFFREQ and TRQTRANS and add MAF and EQIVRATIO and take another log (keep channel count at 24 or less)...

After a freeway burst (over 55 mph, lots of throttle), when you come back down to idle, the PCM may test the cats, you will see the commanded EQIVRATIO transition rich then lean (or vice-versa) for a few seconds and then back to stoich, you will see the front O2 sensor respond to the EQIVRATIO transitions, the PCM times the response of the rear O2 wrt the front O2, if the response time is too short it fails the test (DTC P0420 or P0430).

In your log I can't see any places where the PCM might be running the test, so take another log (at least 65+ mph, lots of throttle).

[aaronr]

Joecar,
I did the log file way you asked looks like the rear 02 responding to slow. Can please take a look.
Thanks

[joecar]

That log file shows the cat monitor test running two times (see the EQIVRATIO cycling when VSS is zero).

In each of those tests, the bank1 rear O2 responds in too short a time, so the test fails the bank1 cat; in attached pics, see rear O2 response time 5->6 for bank 1;

the bank2 cat looks like it's about to fail also.

With the scantool, you can look at the Mode $6 data to see how much the cat test failed by... connect scantool to vehicle, goto ODB-II tab, goto SMS subtab, look at the last 2 entries (OC/60 and OC/70) they show the measured response and the maximum allowed "shortness" of response time (i.e. minimum response time).