Reviving an old thread as I’m experiencing the same thing.
2013 LX with 93k miles.
Driving through some wet slushy snow, the P0607 code came on. I’m running a ScanGauge II so I was able to reset it while driving. After about a half hour, it came back. Drove it home and parked it for the night. This morning I reset it and it stayed off. While driving 6 miles to work, it came back. This time both P0607 and P0138. I parked inside the shop so I could work on the platform and let it dry out. Once dry, I rolled underneath and couldn’t see any obvious issues with the o2 sensors or their connections. The LX is parked in my garage now and the lights are currently off but I assume they will be back.
Anyone have any thoughts on this? And which sensor is Bank 1 Sensor 2? I might as well order one during the Toyota Black Friday 25% off sale.