I have a 2005 Toyota 4Runner with 195k miles. On short trips around town it is fine and doesn't throw any codes. If driver a little further and reaching highway speeds it regularly throws a P156 or P158 code (Bank 2 sensor 2 voltage low or high respectively). I inspected the wires from.the O2 sensor and found no damage. It doesn't have any large exhaust leaks but would need to do a more thorough check to see if there are small leaks. I did change the sensor out but the codes still coming.e in. The times I have monitored the sensor voltage levels it seems to track well with the sensor on bank 1. When I check the freeze frame data for either code, the bank 2 sensor is only 0.2 (or less) lower or higher than bank 1. Any ideas?
Realize this answer your mainly reports problems in the car and rarely on Toyotas is it the sensor itself that causes high or low. Things like intake vacuum legs dirty fuel injectors weak fuel pumps bad mass air flow sensors those can all make that code trip it can get really complex as they age. But doing it up change the filters perhaps have the fuel injection cleaned professionally by a mechanic and pray it goes away
