After replacing sensors and cat, I continue to get the check engine light after it's been cleared?

bank 1 sensor 2 is not the upper sensor, it is behind the cat converter, replace it, disconnect the battery and go drive it to somewhere to have the codes cleared. It will relearn the fuel table to run properly

i would start with o2 sensor that's after the cat and clear code! if still not good then move to the next one till you have it right!

If the cat is bad, it will have to be replaced-and aftermarket cats are much less expensive. Since you say the car runs well, however, I would question why they feel it needs to be replaced. A cat can get 'plugged' from constantly trying to remove unburned hydrocarbons from a poorly running engine, causing a bad problem to become worse. Yours is not the case-although they want you to replace the front O2 sensor, which will improve how the car runs,especially if it is the original O2 sensor.

I would replace the Sensor in front of the cat, clear codes, and go from there-does your cat get cherry red when the car has been driven for an extended period of time? If not, it should not be a issue. The O2 sensor behind the cat only monitors catalytic converter function, and will not affect how the engine runs, period. I

If you have doubts I think you might get another opinion, from a local non-dealership since you got bad advise from that dealership. I would think they would replace the old front sensor, clear codes, and see if any come back-if the car is running well, they will conclude the cat is not bad (it is not) and they might suggest replacing the rear sensor since it too can may not effectively be properly monitoring the cat efficency anymore. You do not need a dealer to install Os sensor(s), and a name brand sensor will work just as well as an OEM sensor, and cost much less in most cases.

ok lets do this in order
P0420 Catalyst System Efficiency Below Threshold (Bank 1) an o2 sensor bad usually before the Cat converter P0430 Catalyst System Efficiency Below Threshold (Bank 2) same thing but the sensor after the cat converter the c1734 people will say you need to replace a bad BCM, but don't,, once the O2 sensor problem is addressed , that code will clear , it has to do with the remote start b2090 has to do with power doors ,, this will drop off too once the system is rest , same with the last one you listed, If I was you I'd have the 2 O2 sensors checked, replace the bad one, or both, and have the mechanic clear all the codes, then recheck them

I could be wrong but that sounds like maybe an oxygen sensor (bank 1). Not sure what code i had on my car but the only bank 1 and bank 2 I heard of is the oxygen sensor but you can always go to autozone and they can check the code and tell you what it is.

the lambda probe(oxygen sensor)is located between the exhaust manifold and the first box(cat)
sometimes the probe is fitted to the cat itself(depends on market)
its the only part of the system that has wires coming off it,replace this first.....as its a cheaper alternative to replacing the cat itself.....if the cat is not faulty.....

cat might be burnt it might be a bad sensor or a broken wire in the o2 sensor

The check engine light is probably indicating a catalytic converter malfunction the Oxygen sensor that is located after the cat tells the computer if the cat is functioning properly it is possible the wire has been broken or damaged. To see if the cat is there jack up the car and look under the passenger and driver area of the car follow the exhaust pipe from the front back the first thing the pipe comes to should be the cat it looks like a muffler with a wire going to a sensor after toward the back side of it, I doubt they never installed one but I guess it is possible.

that car is under warranty for emmision failuare, it a federal law, also you changed wrong sensor poo36 and poo54 mean o2 sensor after the cat-converter is no good not the first one by engine, replace the one after cat and problem will be fixed. good luck.

if the code is for the rear cat o2 sensor i suggested to replace the cat. the rear o2 sensor is to tell the commputer ha good is the cats if the cat not burning the gas. the commputer need to see the o2 sensor to check the cat's