2010 Toyota Corolla 1.8L with engine code P0138

Question

I am receiving the p0138 code. I have replaced the rear o2 sensor, reset codes and even disconnected the negative battery cable to reset the computer. I drove 44 miles before the check engine light came back on. I do have a factory sensor installed now, after learning that the aftermarket that I bought would not work. I don't know what else to do at this point. I have also noticed that my fuel mileage is constantly changing and this is something that I never had an issue with until my check engine light came on. Any help? I wanted to get this car paid off before getting another one but I am about at my wits end!

Answer 1

P0138 -02 sensor circuit high voltage Bank 1 Sensor 2

Circuit high conditions are disconnections of the sensor or poor connections

Here is a Toyota with a P0138 code condition the 02, the harness wire was inspected from the 02 sensors and there is no open circuit condition, what next was to search if there has been TSB, and there has been one from Toyota, TSB # T-SB-0066-10 titled Engine control MIL light on DTC on P0031 / P0138 / P2195. The fix was to give it to the dealer for a warranty The warranty extends for 80,000 miles

Answer 2

So, I've had the same issue and I replaced the sensor on bank 1 sensor 2. However, the check engine still came on. I did a lot of research and went to mechanics. They told me the same sensor is the issue, but i found from one website that the sensor needed to be calibrated at the dealer. I didn't know how true it was, but i took it to the dealer and the sensor i replaced was good, but the bank 1 sensor 1 was bad and needed to be replaced. The dealer did tell me that there is a TSB (I think it refers to technical bulletin board) on P0138 code for my vehicle. They told me that unless it was a dealer the scan tools that non-dealers use don't get any information about the TSB. So, it came to a conclusion that the sensor on bank 1 sensor 2 was probably good, but I think it was a good replacement since my mileage was close to 170K miles. I ordered the sensor 2 from Amazon and it was 50 % less than the auto stores. I just ordered the sensor 1, which is also called air-fuel sensor for lot less than the auto stores. The sensor 1 cost more than the sensor 2. The dealer confirmed that it was the sensor 1 so i have to trust it. Also, with all this issues, i did end up with the scanning tool that shows me the live data and it will give you a hint. Even though i had to pay $99 at the dealer, i hope my experience will help others. If i had dealer to replace this sensor, it would've cost close to $500 with parts and labor.

Comments

I've seen your comment now and I wonder how did you end up fixing your problem.
I have the same car with the same error. Was the problem with air fuel sensor ( sensor1 )