Did anyone ever have this P0135 code? It says Heat Circuit of O2 Sensor.

I am not sure what caused this, but I will be bringing it to the dealer tomorrow. I hope it is as simple as replacing the O2 sensor

 

I took my car in to get the recalls last week. They fixed everything for free except the p0135 code. The mechanic told me it was just an oxygen sensor (before cat). So I ordered that, replaced it, reset the code... and i've been running perfect ever since.

 

what are your mods?

 

Replace your front 02

 

All I have is a AEM cold air intake. Looks like you have a ton of mods. But from what I've seen p0135 is an oxygen sensor issue, mainly the front one.