P0135 code which one?

Question

I have a 2005 civic si. But I also have after market exhaust system. Is this sensor on my engine like some of the other older civics or is mine new enough to not be on the engine?

Answer 1

P0135 A/F heater circuit malfunction

This is going to be the A/F sensor or what is referred to as the 02 sensor, heater circuit of the 02 sensor is what fails more often

Here is the location