Stubborn o2 Sensor issue - downstream, CEL, P0157, bank 2 sensor 2

Hi All,
I had my cats stolen and replaced--at a muffler shop--not Toyota. Toyota, at the time, had a three month wait for OEM cats.

After several trips back to the muffler shop, bank 1 sensor 2 is all good and no trouble codes.
Bank 2, sensor 2 continues to trigger P0157.
I've had four different sensors and same result.
I just picked up the fourth sensor today at Toyota and same result.
I'm reading live data with an Ancel OBD2 reader which has been helpful.
Temperature at catalyst bank 2 sensor 2 is same as catalyst bank 1, sensor 2.

Oxygen sensor voltage is same between b1-s1 and b2-s1.
oxygen sensor voltage output at b1-s2 is in range between 0.1 and 1V.
oxygen sensor voltage output at b2-s2 starts off low and then in less than 1 miles goes to zero.
I can see it raising a P0157 code in less than two miles.
If I drive enough miles--50-60 miles, it throws CEL and of course notes P0157 code.

I've even swapped sensors from one side to the other and I get the same result. B2-S2 low voltage.

The muffler guys has been over both sides of the exhaust and I even had it inspected by another shop that said the welding and cat work is tight and good quality.
the same cats are on both sides---so no differences there --and bank 1 is checking out fine/not throwing any codes with over 250 miles.

I've looked at the connectors and the wiring and I see no obvious damage, but I have not pulled stuff apart and dug deep into that.

Another shop mentioned that IF it were the ECM or computer, it would flag immediately and it wouldn't wait for the 50-60 miles to throw the CEL. He said to focus on the sensor. I'm on my fourth sensor(last one OEM/Toyota).

I appreciate helpful feedback. Thanks!!

 

I've got something similar going on with my 2007 4.7 Except my cat on #2 bank RH side basically burned the internals
right out. So after getting same codes I replaced the RH cat and all 4 O2 sensors. Ran fine for a while, all of a sudden
same code on the same side. It's the #2 O2 sensor again. What I can't figure out is it's a brand new cat. Literally.
Less than couple hundred kilometers. Can't be sure but tomorrow I'll check the wiring isn't messed up. I have a friend
who is a code reader so I'll run it again and compare my numbers to yours.
What engine do you have? I'm thinking a 5.7 for 2013 but just guessing.

 

I have the exact same thing happening on my 2016 5.7. Cats got stolen and b2 s2 is now starting at normal voltage and then drops to 0v. I’ve been stuck on this for weeks and my cats got stolen right before I needed a smog. Please post an update!!!