Toyota Tundra Forums banner
1 - 3 of 3 Posts

2 Posts
Discussion Starter · #1 ·
Hi Super smart helpful enthusiasts.

My 04 V8 4.7 Tundra had the code P0031 come up, which is H025 (or H02S) meaning Heater Control Circuit low Bank 1 Sensor 1 (and possibly Bank 1 Sensor 2).

Can I get some help with what this means and the severity?

I susperced it was related to very little heat in the AC, and when I removed the code, it returned when I turned the heat on again.

HOWEVER, in the Haynes Manual the diagrams seem to give a different sense, of a critical one relating to a critical engine function.

What are these and what can be done? Are the sensors easily or cheaply replaced?

I'll attach the electrical diagrams which mentions the heaters/heat sensors and banks.




Premium Member
2,388 Posts
Those codes have nothing to do with the HVAC ventilation system. Those codes are for sensors in the exhaust piping for emission control. Do a search using those code numbers and you'll see what they are for.

1 - 3 of 3 Posts