P0031 and P0138 Codes

2011 2.7L 4X4. Recently had my check engine lite and slip light come on. I got the codes read and P0031 and P0138 came back. Called local dealership for a quote and got this.

BANK1 SENSOR1 1L $398
BANK1 SENSOR2 1L $332

I believe these prices include labor.

$730 seems crazy to replace two O2. Is this an easy job to DIY? Going to bring to my mechanic (not dealership) and see what he thinks....

 

if it is the 02's, parts are about 300 for oem through the dealer.

been years since i replaced one and it wasn't on a tacoma. it's straight forward in how to. rust can make it less than fun.

good luck

 

Thanks. I've done some research and it looks straight forward with the right tools. Is it common for both of these to go at once. I reade the upstream one is the one that actually can affect performance (air to fuel ratio). Downstream is really just an indicator. Is there any downside performance wise to just change the upstream sensor and clear the codes?

 

from 06 manual. i hold no claim to changes between model years

 

i would start by replacing the upstream AFR sensor only. A denso unit can be bought on rockauto for about 120 bucks. Im running this one on my truck currently

https://www.rockauto.com/en/moreinfo.php?pk=1606680&cc=1442969&jsn=413