We have 55k on our 2015 Prius and today we received the P0138 Code. I cleared the code 3 times and the code keeps coming back on. Does anyone know of an easy fix we can try? Thanks for any ideas etc. . . .
The code is going to keep coming back until you replace one or both of the O2 sensors. P0138 is the rear sensor specifically, reading high voltage. That could be because the rear sensor itself is faulty, or because the upstream sensor is faulty and the engine is running rich. Have you noticed a change in fuel economy recently?
I have own the car since new, completed all schedule maintenance etc., and the car has been (and is) running great with MPG in the low 60's. My last trip was 71.1 mpg over 27 miles. I am also shocked that the rear sensor or front air/fuel ratio oxygen sensor could be bad at just 55K. This will be the first repair on this vehicle to date other than regular maintenance. I wish there was something else I could try first. . . . . . .. ..
My guess is rear sensor then; they're around $100. Little things like this can happen on any car; a wire rubs somewhere, wearing away the insulation, and it shorts to the metal body or another component, for instance.
Just a quick follow-up question. Where did you find this sensor for $100? The cheapest OEM I found was $180 plus tax and shipping. Thanks!
