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code po138 bank 1 sensor 2 I replaced this sensor and same code came right back I then replaced bank 2 sensor 2 just in case I was miss informed as to which side is which. still getting po 138 bank 1 sensor 2 code. Does anyone know why this might be happening????
 

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code po138 bank 1 sensor 2 I replaced this sensor and same code came right back I then replaced bank 2 sensor 2 just in case I was miss informed as to which side is which. still getting po 138 bank 1 sensor 2 code. Does anyone know why this might be happening????
make sure you replaced with genuine toyota part
 

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Yeah get the correct sensor. I put a bosch in and the exact same code came back probably 20,000 miles later. Haven’t touched any of the other 3 in that time frame. I think Denso is the oem for o2 sensors on these trucks so get that brand


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i always buy from toyota lil bit more expansive but last longer,( if you tell you work for some shop they will give you discount)
 

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Have you done a test on the sensor to make sure it's working correctly? about a month ago I replaced sensor 2 on bank 1 the problem continued as soon as I turned the truck back on. I tested the sensor and it was bad, went back to Toyota and got another one a day later, put it on and the problem was gone. Also make sure to use genuine OEM parts as the other members suggested, they're pricey but worth it. take a look at this video on Youtube, it may help you with the test.
 

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Have you done a test on the sensor to make sure it's working correctly? about a month ago I replaced sensor 2 on bank 1 the problem continued as soon as I turned the truck back on. I tested the sensor and it was bad, went back to Toyota and got another one a day later, put it on and the problem was gone. Also make sure to use genuine OEM parts as the other members suggested, they're pricey but worth it. take a look at this video on Youtube, it may help you with the test.
I had sensor 2 code. Somewhere online someone said it is usually the sensor 1 that is faulty but no. 2 gets the credit. I changed the ones and that worked for over a year. The codes for 2s came back and doing 2s fixed it.
 

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I would verify and Ohm out the wiring from the rear O2 sensor(bank 1 sensor 2) to the ECM next and if that all checks out replace the upstream Bank1 02 sensor (A/F sensor). I always replace the upstreams as a pair and recommend it especially if you are over ~150k miles. The problem is most likely the bank1 upstream sensor as the computer just compares the rear to the front sensor. If that doesn't fix it the only other thing is a bad ECM input and swapping ECMs would be next however I would triple check all the sensors and their wiring before just swapping an ECM. EDIT and ALWAYS use OEM Denso Sensors... Toyotas don't like german crap.
 
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