Air Fuel Sensor (Upstream Oxygen Sensor O2) reading P2238 code, was replaced OEM Denso Brand New

P0171 and P014C codes popped up on 2012 Prius 210K miles | PriusChat

need a head wiser than mine. I have a 2012 Prius with approx 212K odo. I was running into a P0171/P014C, ran tests in Torque Pro and saw the voltage reading on the A/F Bank 1 Sensor 1 for the heater was reading below threshold. Given that it was old and original, I figured the O2 sensor went bad, so I went ahead and ordered an OEM Denso from Rock Auto based on the Toyota Part Number replacement.

Now, I am running into a P2238 code, which only occurs when the Prius is cold/just starting up. Can anyone help me with diagnostics? Also, there is a bit of a oil leak on the rear valve cover area that is directly dripping (slowly) in that area. Is it possible that this is causing the sensor/wiring to short?

Where is the Prius Engine Control Unit (ECU) located?

 

I thought about that, yet was trusting that the one new in the box was the right one. You're definitely right about the tolerances. I should have done a better job and tested the resistance of the new one out of the box just to be sure it wasn't the wiring or ECM.

 

So going off the old one, I ordered based off the Toyota Part number from Rock Auto, which puts this sensor as a direct match: More Information for DENSO 2349301
On the bottom of the page, it even says the OEM Toyota Part number off my original O2 sensor as a match.

However, when I use the PULLDOWN menus on Rock Auto's site, it shows this Denso part instead: More Information for DENSO 2349112
The OEM interchange at the below doesn't even come close to my old part number, so wondering, was there really two types of O2 sensors used on the 3rd Gen?
2010-2011 weren't different motors or exhaust in anyway, were they? The only physical difference I see is that the first one has a flange/heat shield while the second one doesn't. Physically, the old original O2 sensor on my car matches the second item.

To make things even more complicated, Denso's website via pulldown says that the 2nd one is the correct part number as well. I'm a little peeved at Rock Auto because they won't let me return the wrong O2 sensor despite having the wrong interchange info on the product support page.