Faulty O2 Sensor P0300 alone with Secondary DTS P0301, P0303, P0305 and P1130?

Okay. So, you got to replace the rear oxygen sensor under the seat. But these readings are in Open loop operation while the engine is still too cold. Get the engine up to full operating temperature first, you'll know when the "Fuel System Status" reads CL. Thats Closed Loop operation and the ECM will be taking readings from the front AF sensors and the rear Oxygen sensor. I still see 0.0volts on the rear oxygen sensor. It should be higher than that. The 3.3volts on the front AF sensors (oxygen sensors) is just a biased voltage the computer puts out. The AF sensors work off of current flow and not a voltage reading. But the rear oxygen sensor is a standard regular oxygen sensor. So, I would expect to see at least 0.5volts on that steady once the engine warms up.

If these readings are after a 20min drive, then there is an issue with the thermostat or cooling fans staying, something that is not allowing the engine to get up to operating temperature. 177 degrees is too low. The thermostat for this vehicle should be opened 10mm at 203f degrees, if your scan data is not reading over 177f the vehicle is never reaching a temperature that can allow it to go into Closed Loop. And the Oxygen sensor output voltage (B1S2) being still at 0.0volts isn't correct.

It's possible you have a wiring issue somewhere, or a corroded connector, but 0volts looks more like an open circuit, where the signal is not even reaching the ECM. So, take it for a longer drive or allow it to idle for 30 min and then check the live data PIDs again. We need to get it up to operating temperature. I'm going to get the info together on replacing the thermostat. On your first post with live data, you had a coolant temperature reading of 192f but still in Open Loop. And I'm not sure why that scan tool is not reading any engine RPM at all.

One other thing I see is that you have 7 IM Readiness monitors and only 6 of them are complete. It's on the first data screen. Try pressing the I/M button and see which monitor has not run. The IM (Inspection/Maintenance) monitors are self-tests the ECM runs on the vehicles systems. They should all be complete. Any time they wouldn't be is if there is a problem (failed test) or if the battery has recently been unhooked and they haven't had a chance to run yet. I will also see if I can find where the rear oxygen sensor wiring runs, we know it comes into the vehicle under the seat, and the ECM is located on the passenger side behind the dash, so maybe behind the glovebox. But we need to see a voltage reading from that sensor. Unless this is something to do with the scan tool not giving accurate data. I have never used one of that brand before. But I know it's giving you global OBD2 data, and not manufacturer data. But Global OBD2 should be sufficient. Toyotas are more technical when it comes to their electronics. I think they are one of the better vehicles out there, but they are more difficult with their labelling of components and such.

But I would recommend getting a reading with some external temperature probe of the thermostat housing and see what you get. The thermostat might be getting stuck halfway open and/or not closing all the way.
That 2nd picture of the oxygen sensor looks like it possibly overheated, but my main concern is that you're driving around all the time in open loop where the engine computer is mainly calculating its fuel strategy on the engine coolant temperature sensor, when it should be taking data from all the sensors in Closed Loop, and it has to reach its full operating temperature to do so.

Again, sorry for the long post, I will also take a look at the Rav4 service info as well really quick, if no one has gotten back to you, you can post again, and it will show up as a response to the tech that was helping you. I'm not sure I will be able to find it being that far back. But I'll take a look myself after I get the thermostat information.

Take a temperature reading at the thermostat location in the diagram below.

https://www.2carpros.com/articles/how-an-engine-thermostat-works

Okay, that reading on B1S2 oxygen sensor voltage of 0.7volts is what I would expect to see on that sensor, so that's good. If you press the I/M button with the key On, does your scan tool list which IM monitor has not passed yet? I'm just wondering if it's the Oxygen sensor monitor that hasn't had enough time yet to complete the IM readiness since you replaced an AF front sensor. You can see by the 1st chart it takes about 10 of these cycles to complete the Oxygen sensor monitors. The vehicle is running somewhat lean at idle.

I ran a VE test with your live data values and the Volumetric Efficiency was low. Being a 3.0liter engine, a rule of thumb is the Mass air flow sensor should be at about 3 grams per second at idle. Your vehicle is running at 2.65g/s, but since you haven't mentioned any running issues, this can be a vacuum leak, or an under-reporting mass air flow sensor. which would explain the low mass air flow reading and the high fuel trim numbers.

Bank1 is about +8.6 percent and Bank2 is about +10.9 percent. So, if these numbers don't come down after a while, looking for a vacuum leak will be next. If the Fuel Trim numbers come down at higher RPMs (2,000-2,500 RPMs), that points to a vacuum leak. The Equivalence Ratio (lambda) should be around 0. Where it's at 0.997 now. So, the front oxygen sensors are indicating a lean condition. But those fuel trim numbers are too high. Let's see if they come down some with some drive cycles. Cleaning the mass air flow sensor might help, auto parts stores carry mass air flow cleaner spray.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Okay, I will go over these data PIDs and get back to you shortly. But I already see a huge improvement.

Okay, I've gone through all the data, and everything looks really great, the fuel trims are almost perfect, the Air/Fuel sensor voltages are great. When the MAF was at 0.47lb/min (3.55g/s), engine RPM 786, that's a much better Mass air flow reading, I'm just wondering at what point it went back down to 0.36lb/min (2.72g/s). How does the engine feel? Does it have good acceleration? For some reason the Volumetric Efficiency test keeps failing. But if you have full power back, and nothing is setting any codes. We won't worry about it too much. The only real reason I'd see it fail this test would be a restricted exhaust, but all the live data doesn't really point to that, unless you're noticing a performance issue. Even the Bank 1 Sensor 2 oxygen sensor voltage of 0.5v looks better. All 7 IM monitors passed so that's all good. I'm not sure why these VE tests are coming out like this. The 2.72g/s on the MAF at idle is a little low still, not sure why your data is jumping around like that. But with all passed IM monitors, we won't worry about it unless you happen to notice a lack of power. If the Converter is partially clogged, you would notice it on a wide-open throttle test. There would be a hesitation as if the vehicle was pulling a heavy load. But if it's okay, just drive it and we'll address any issues that come up in the future.

It's no problem, that's what we're here for, I'll look into this VE test some more and see if there's a logical reason for it failing. I might try a different test as well. The VE test pretty much shows how well the engine breathes (takes in air and pushes out exhaust). Take a look at your air filter too. It's probably the most neglected part of the engine. If it has been a while, just change it out, they're cheap enough. So, if I have some epiphany about the test results Ill post them here. In the meantime, have a nice day.

Okay, I found the reason; the VE test needs a Wide-Open Throttle run and then input the recorded data at the highest RPM. So, at idle the test is not enough data. So, nothing to worry about.

I wouldn't worry about doing it at all. You would need to be recording live data at the same time, and you have to be extremely careful. So, disregard that test. The live data all looks great. So, no further testing is needed right now. The MAF cleaning helped a lot. A WOT test is something a technician should do, plus I don't want you to get a speeding ticket. Just let us know if you have any other problems in the future.