1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2015 Prius P0138 Code Fix?

Discussion in 'Gen 3 Prius Technical Discussion' started by bear15, Jul 14, 2020.

  1. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    168
    35
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    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. . . .
     
    #1 bear15, Jul 14, 2020
  2. Vman455

    Vman455 Senior Member

    Joined:
    Feb 8, 2014
    534
    551
    13
    Location:
    The Middle
    Vehicle:
    2013 Prius
    Model:
    Two
    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?
     
    #2 Vman455, Jul 15, 2020
    bisco likes this.
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,132
    50,047
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    strange at 55k, what is the cars history?
     
    #3 bisco, Jul 15, 2020
  4. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    168
    35
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    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. . . . . . .. ..


     
    #4 bear15, Jul 15, 2020
    bisco likes this.
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,132
    50,047
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    what are you reading the codes with?
     
    #5 bisco, Jul 15, 2020
  6. Vman455

    Vman455 Senior Member

    Joined:
    Feb 8, 2014
    534
    551
    13
    Location:
    The Middle
    Vehicle:
    2013 Prius
    Model:
    Two
    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.
     
    #6 Vman455, Jul 15, 2020
  7. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    168
    35
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Thanks for the information.

    I wish there was something else I could try first. . . . . . .. ..

     
    #7 bear15, Jul 16, 2020
  8. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    168
    35
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    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!

     
    #8 bear15, Jul 16, 2020
  9. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    168
    35
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Fixed: The problem was rear sensor wire chewed by a rodent of some kind and we replaced the sensor.

     
    #9 bear15, Jul 18, 2020
    pjksr02, ASRDogman and Raytheeagle like this.
(You must log in or sign up to post here.)