My car popped a p0036 code yesterday morning. I reset it this morning, it came back on. My scanner says "heater control circuit bank 1 sensor 2." I replaced the wiring harness and both o2 sensors 30,000 miles ago, so it seems unlikely they would be bad already? If they are, I'm a little pissed.

Where do I start? I also don't know if this could be related, but the night before I drove through a really bad storm for several hours. Could some water have gotten in somewhere and be throwing it off?

 

I would start by replacing the #2 o2 sensor. That's the easy one, on the bottom (after the cat).

 

I guess that would be the easiest thing to do but before I shell out $100 for a new sensor that may not fix the issue, I'm wondering if anyone had any tips on testing them first?

 

If it were me, and it is because I'm doing the exact same thing, I'd pick up a cheap one (less than $20) on amazon just to test it out. And if that does solve it, you can replace it with the more expensive version later if you need to.

 

Well, before you spend any money, you might want to look under the car and see what is going on. I just crawled under mine, and found that some rodent or something chewed the wiring (on the connector side, not on the o2 sensor, unfortunately). Now I'm going to have to figure that out.

 

Maybe not. On the car's 3rd #2 O2 sensor here, averaging 25-30K miles per sensor. Stock set up other than the OEM diameter ATI crank pulley.