Hi, this forum looks awesome! I have 2 Toyota's a highlander and an 07 Camry with almost 1/4 million miles! I have a P0420 on the Camry. It sounds silent when it runs. I doubt it is the CAT but wonder if anybody could tell with the Freeze Frame what it might be. Could be the CAT, it is just so quiet.

Here is the Freeze:

DTCFZF P0420
FUELSYS1 CL
FUELSYS2 N/A
LOAD_PCT(%) 60.8
ETC(°C) 194
SHRTFT1(%) -4.7
LONGFT1(%) 1.6
RPM(/min) 1576
VSS(km/h) 48
SPARKADV(°) 19
IAT(°C) 41
MAF(g/s) 1.634
TP(%) 21.2
O2B1S2(V) 0.7
RUNTM(sec) 1394
EQ_RATB1S1 0.961
o2B1S1(V) 3.027
EVAP_PCT(%) 79.2
WARM_UPS 5
CLR_DIST(km) 40
BARO(kPa) 28.9
EQ_RAT11 0.961
OsS11(mA) -0.168
CATEMP11(°C) 1297.04
CATEMP12(°C) 1079.6
VPWR(V) 13.906
LOAD_ABS(%) 37.3
EQ_RAT 1.034
TP_R(%) 3.1
TP_B(%) 54.5
APP_D(%) 20.8
APP_E(%) 36.5
TAC_PCT(%) 20.8
CLR_TIME 1h:37m

 

Your issues are limited.

Exhaust leaks ahead of CAT yes/no?
Bad A/F ahead of CAT or O2 behind.

With engine operating in close loop (warmed up).

O2B1S1 voltage should vary between 3 and 3.3 ish volts.

O2B1S2 Should be steady voltage at 0.7v. If alternating between say 0 and 0.7 volts the issue is the CAT.