02 Tundra 4.7L O2 Sensor issues

[airboss20]

I know this may be redundant, however there are conditions. I made the mistake of purchasing a couple cheap O2 sensors as my replacements for the rear sensors on both sides. Of course both of them malfunctioned within a year. Now I have replaced them with Bosch sensors.

My issue is that I am reading 4 codes on the scanner. They are P0136 B1S2 O2 malfunction, P0141 B1S2 O2 sensor heater circuit malfunction, P0156 B2S2 O2 malfunction and P0161 B2S2 O2 sensor heater circuit malfunction.

I had thought that the heater sensor malfunction codes would have cleared relatively soon, followed by the sensor circuits. This did not happen. I drove a 3 mile stretch of the highway 10 times, fulfilling the required high speed allotments. I then drove a 1 mile stretch of town road, fulfilling the low speed allotments. I was sure to wait at least 10 seconds at idle between each leg.

Could the vehicle side of the heater circuit have gone bad, not supplying the proper voltage to the sensor? I am at a loss here.

[airboss20]

I had the very same issue with mine last year. I too bought the cheap sensors before shelling out for the Bosch The heater circuit codes will not clear by themselves. I drove around for almost a month before I discovered that you have to erase the codes and complete another drive cycle.

Hope this helps!