OBDII is a federally mandated protocol that all cars engine controllers must use. It mandates that the engine controller must monitor the engine and emissions system for proper function that would effect emissions and do periodic tests on the emission equipment.
OBDII mandates a test of the Catalytic Converter and to set a code if it fails the test. That is the code you have, one of your two Catalytic Converters has failed the test. Bank 2 usually means the right bank, from the perspective you sitting in the driver seat, i.e. the right Catalytic Converter from that perspective.
Chrysler, and just about all vehicle, have an O2 sensor in the exhaust to sense what the Air/Fuel ratio is, the amount of O2 in the exhaust is directly proportional to the A/F ratio. This is how the engine controller keeps emissions down and gets better fuel economy.
The way Chrysler, and few others, test the Catalytic Converter to tell if it is working correctly, is to install a 2nd O2 sensor in the exhaust after the Catalytic Converter. The engine controller then compares the O2 sensor outputs from the exhaust before and after the Catalytic Converter. If the Catalytic Converter is doing its job correctly, it will cause by-products in the exhaust to chemically combine to more inert compounds. These by-products chemically combining will consume oxygen in the exhaust and the exhaust coming out of the Catalytic Converter will have less oxygen than goes in. Thus the output of the O2 sensors should be different. If the output of the O2 sensors is the same, then the Catalytic Converter must NOT be consuming any oxygen, i.e. NOT working at all, and thus it fails the test and lights the code.
So, its possible bad O2 sensors might be giving the engine controller bad information to make it wrongly assume the Catalytic Converter is bad. But think about the probabilities.
- If an O2 sensor goes bad, it should trip a code for a bad O2 sensor. Although it is possible for an O2 sensor to be out of calibration or bad and NOT trip a code.
- The Catalytic Converter only fails the test if both the before and after O2 sensor output is the same. What are the chances an O2 sensor goes bad or off calibration just right to match the output of the other O2 sensor?
Its possible, but NOT likely its a bad O2 sensor, either upstream (before) or downstream (after) O2 sensor could be bad (but failed in a way to NOT set a code and also match the other sensor output). You have 2 O2 sensors per bank. So Bank 1 says the O2 sensors and the Catalytic Converter are good, a quick test to confirm if it is or isn't the O2 sensor is to swap the O2 sensors from Bank 2 to Bank 1. If it was one of the O2 sensors, then Bank 2 Catalytic Converter would pass the test and turn off the code, but now Bank 1 Catalytic Converter would fail the test and turn on the code for that. If the Bank 2 Catalytic Converter still fails the test and Bank 1 still passes the test, then it can't be the O2 sensors.
In short, swap both sensors to opposite side, if the problem follows the sensors to the other side, its the sensors. If the problem remains on the same side with the known good sensors, then the problem has to be the Catalytic Converter. It takes several hours of driving if NOT several days before the engine controller runs the test. I would Clear the Codes before driving with the swapped sensors, i.e. reset the PCM by pulling the battery cable for an hour.
Its NOT so quick, those sensors seize in the exhaust from heat and can be a bear to get out, NOT to mention they need a 20+mm wrench that typicall is NOT in most folks tool box.
I have NOT looked up part numbers for the Commanders O2 sensors, but usually vehicles multiple O2 sensors use all the same O2 sensors, they only differ by the length of the pig tail, cause they are different locations, which would make it a different part number.
Remember, the Upstream O2 sensor is used for feedback to manage the engine A/F ratio, you have one for each bank on the engine. The Downstream O2 sensor is just to test the Catalytic Converter, also using the Upstream O2 sensor, you have one per Catalytic Converter. Since you have 1 Catalytic Converter per bank, you also have one Downstream O2 sensor per bank. Since the Downstream O2 sensor is farther away from the engine (and engine controller) it typically has a longer pigtail to the wire harness.