O2 Sensors Codes Showing for Bank 1 and 2

New to the forum so not sure if this is a new topic. I have a 2008 Tundra TRD 5.7 with roughly 77k miles. Check engine light came on and my OBDII sensor is giving me P0031 and P0051 both are generic codes for HO2S Heater Control Circuit Low Bank B1 and B2 (P0051) Sensor 1. I was skeptical that both would go at the same time; I'm also showing an OL-Fault which isn't surprising with the other codes. Tested for resistance at the sensors black wires and both are showing 2.7 ohms. Tested the other two wires on pigtails on the wiring harness coming from the PCM, B1S1 tested 2.909 volt on one wire and 3.309 volts on the other, B2S1 tested 2.912 volts on one wire and 3.310 on the other. Everything looks ok but I went ahead and bought a new sensor from Toyota to see if it would clear one of the codes. It did not and I'm still getting the two codes. Has anyone else gotten this before? Any ideas on what could be going on?

 

Did you ever find a solution? I have the exact same problem.

 

I have the same problem with a 2008 Tundra 5.7. The relay is built into the fuse box and a pain to remove. I’ve ordered one. The fuse says a/f and it’s a 15 amp wasn’t blown. I’ve check all the resistances and power at the front 02 sensors. Tried just answer for assistance and yes all 4 02 sensors, calls, are new. Tried variety of o2 sensors old and new no luck. It’s a hard code. ECU ordered. Hoping it’s the relay. All wiring tested continuity also. Any ideas?………

 

Did you replace the relay? Did that fix the issue. I started receiving the same issue at once P0031 and P0051 after an oil change and blowing out dirt and dust from the engine compartment (including the fuse/relay box location).

 

It ended up being the incorrect AF/02 sensors. I now have a Bank 1 lean condition p2195 I think. I’m changing the fuel injector O-rings and filters next. Also getting P0420 which is caused by the Bank 1 sensor one issues I’m sure.

 

Hey @Franklbecerra1 how did you solve this problem. I did the same idiotic mistake of blowing out the dirt from my fuse box and I started getting both these codes P0031 and P0051 Heated Oxygen Sensor Bank 1 & 2 errors. Its a pending code.. and is not going away. Does it have to do anything with the fuse box or any fuses or relays?

While this is happening I also have a water pump leak which I have to fix. This was the initial issue I was dealing with. Shoot why did I try to clean my fuse box..

Ooh and just doing some Troubleshooting of the wiring diagram I found the following the Heated O2 Sensors are D32 & D31 on my 5.7l 3UR engine showing below. Looking at the light green wiring it does show up close to the fuse box (right above the blue box on the right side). I'll first try to see if those wires are hook up properly.

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Thanks