Civic EG

OK, i just replaced my headgasket, upper and lower radiator hoses, and some other various hoses. I get it all back together and bleed the coolant and bam, that yellow light of doom pops up. Check it out and its the vtec spool valve. check the connection, wah lah! not connected all the way, reset the ecu and check the codes again. Nada. relief floods over me. I didnt screw something up. Then on my way home(did the repairs at the dads house) the damn yellow light of doom pops back on. Check it when i get home and its the primary o2 sensor heater. WTF!?!?! I have a heater for my o2 sensor?? Whats the deal with this?

crack in the header?, loose wire in the connector?...

its still the stock manifold, so I guess there could be a crack. Ill check the wires the next time I get a chance. I just didnt know my car had an o2 sensor heater... I thought thats why its so close to the head. to get heated faster.