Hi all, I am new to this site, I have a 2002 blazer 4.3, with a p0155 code for the bank 2 sensor 1 heater circuit. I looked at a diagram for this circuit and it shows a pink wire as battery voltage. my vehicle has the pink wire going to the post cat sensor and it is hot. however on bank 2 sensor 1, I have two green wires going to the heater. One wire goes from a connector along right side of engine down in the main loom going to engine. The other green wire goes to the pcm. neither wire is hot with key on. Does the power for that heater come from the pcm, or from the green wire with a white tracer that goes up in the loom in front of the fire wall.