Oxygen Sensor Error Codes

I have a 2020 Tacoma SR with ~35k miles on it. Recently, a p0051 error code got thrown. I tried to fix this on my own and replaced the bank 2, sensor 1 error code with this part

$39 Walker Products 350-34258 Oxygen Sensor, Original Equipment Replacement Premium O2 Sensor,

https://www.amazon.com/dp/B01IAFTXHM

After replacing, the error code p2240 error code got thrown. It also seems the original error code, p0051, is also not fixed.

Does anyone have any ideas what might be going on here and have any suggestions for fixing it? I'm a very novice mechanic, so please don't assume deep skills.

 

I feel like this would of been a warranty concern. However, start by getting an oem or denso or ntk/ngk o2 sensor.. yes it will probably be expensive but walker kinda sucks.

Next look for a wiring diagram for the heater side of your o2 sensor and check for battery voltage there at a cold start. If that's not present then find and replace said fuse (most likely). Also do a continuity check between the same two power and ground terminals to ensure they aren't shorted together somewhere. Once you have confirmed voltage there then clear your code and try again with the new o2 sensor from the recommended 3 above and go from there.

Old sensor could of shorted internally in the heater side and the new o2 sensor could just already be junk

 

Thanks for the info.

Is this a good replacement for the walker sensor?

$107 NTK 24661 Oxygen Sensor

https://www.amazon.com/NGK-24661-Ox...8-1-5292-392-1&vehicleName=2020+Toyota+Tacoma

 

Yes but check out rockauto, alot of counterfeits on Amazon.
Also what were the results of the voltage check, short circuit check and fuse check?

 

OK, thanks.

After a cold start, I’m gettin battery voltage of 0.4 V. When I test the resistance of the old and the new sensor, I get between 11 and 15 ohms. When I test the sensor voltage of the new sensor using my obdII scanner, I get a constant 3.3 V.

What do these values indicate to you?

 

If you're positive you're on the heater circuit and only getting 0.4v on a cold start then thats most likely your problem there. You should be seeing battery voltage. Check the o2 sensor heater fuse to see if it popped. Otherwise resistance seems okay. Maybe a little low but tbh I dont recall what it should be. The 3.3 volts sounds alright. Thats for the monitoring side of your o2 sensor.

Edit I apologize and from here out with refer to it as a a/f sensor as it actually is and not an o2 sensor

 

Both the a/f htr fuse and relay are intact. They didn’t look broken and I swapped them with others to check. Could it be an issue with the harness leading to the a/f sensor itself that’s the issue? My obdII keeps recommending that I replace the harness as a response to the p2240 code.

 

It could be a harness side issue for sure. Just the other day I was helping my buddy with a p0050 code on his ranger. His issue was the wire broke at the terminal into the plug so until you gave the wires a little tug everything seemed fine. P0050 is a similar code. Main difference is that p2240 from what I can figure is specifically saying you have an open in the power side of the circuit. Where as his code was more a general circuit issue.

Aside from the tug test I briefly mentioned, you can try getting a helper to hold the connection with the multimeter at the sensor plug then follow the harness wiggling and moving it until you see a reading on the meter or a flicker of a reading. That should find you the open in the circuit

 

How many miles? You should still be under factory powertrain warranty and/or emissions warranty.

 

Thanks, @joba27n, I'll try this.

@Arries289 it has about 35k miles on it and I've had it for about 3.5 years. I think the powertrain warranty just expired, right?

 

Negative, power train is usually 5years 100'000kms (60'000mi)

if you bring it in now may sure you put the factory sensor back in