2009 Tacoma 4.0 P0031, P0037, P0051, P0057,P0102

Hi - New Member here looking for assistance. I just purchased a 2009 Toyota Tacoma 4x4 via an Auction in Arizona with only 97K Miles. From what it appears the Vehicle belonged to a Municipality and sat for 9-12 months with a Dead Battery. Unfortunately the Municipality would not release any Maintenance Records but according to Carfax the Vehicle was maintained regularly at a Toyota Dealership and there is no indication any parts were replaced. The Vehicle has multiple Warning Lights on except the ABS Light and with a Code Reader we found the following DTCs:
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P0031 - O2 Sensor HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
P0037 - O2 Sensor HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0051 - O2 Sensor HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
P0057 - O2 Sensor HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
P0102 - Mass Air Flow (MAF) Circuit Low
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Truck has a hint of a Gasoline odor when running (no leaks were seen anywhere) and the fuel mixture seems pretty rich. It runs fine at Freeway Speeds and we have done a Throttle Position Sensor Reset which seemed to have cured a rough idle for the most part. Regarding the DTCs a web search indicates first thing to check would be the Fuse Box Fuses and AR Relay which I plan to do. Judging by the similarity of the DTCs, I was also suspecting a bad ground someplace. Coming from Arizona's dry climate, the underside is darn near immaculate with no corrosion seen anywhere.

I am trying to debug as many things as I can prior to enlisting the help of a very competent Mechanic but he's $125/Hour. Would anyone know if there is a common ground for the O2 Sensors and the MAF Valve and if so, where would it be located. The Truck is currently in a Storage Facility away from Home and awaiting Catalytic Converter Shields (I live in Los Angeles and Vehicle and Converter Theft here is rampid...) hence, I'll bring any info seen here with me the next time I am with the Vehicle. Thanks in advance for any information you can supply.

 

I think you’re on the right track, A/F relay, fuses or loose grounds. They don’t share a separate grounding point I think it happens in the ECU so would just be the main engine block grounding point. Did you clean off the battery terminals real good too, and confirm the ground cable isn’t corroded? Sounds like a great find on a low mileage 2nd gen, happy for you!!

 

Just an fyi and if it helps in this situation

Since personally going over to an all Toyota family, (2 Tacoma,s Sienna, Prius, several Scions), I've noticed a Toyota thing in general is a heavier than normal hydrocarbon (unburnt gas) smell on start up. Sinve the code indicate low resistance I'd suspect garbage aftermarket o2 sensors as a starting point.

The maf has also been a high on the failure rate thing. They are delicate and cleaning is only good for so long.

 

Check the EFI No2 fuse, I bet it's blown.