Check engine light code P0135 025

[h2con]

I have a 03 H2 that has had the check engine light on for about a week. I just dug up my Predator programmer and got the code p0135 025 heater circuit, Bank 1, Sensor 1, Malfunction. I removed the code, started the truck and the check engine light was off. My truck has about 69k miles on it. Is this a sensor I can replace myself? Should I wait for the light to come back on or take care of it now?