So I finally got around to checking my sol's check engine light. I got a code 43. Any ideas what it could be? I'm reading it might not be just the oxygen sensor.

 

could be any part of the fuel system

 

My bad, code 41 lol. What is a "primary oxygen sensor - heater"?

 

Its generally the sensor before the catalytic converter.

Halfway down the page if your car is OBD1
https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

 

It means there is something malfunctioning with the heater circuit of the 02 sensor. Its quite common and is part of the o2 sensor. Check the heater circuit for voltage at the plug of the o2 sensor. Then check the ground side. If that checks out replace the sensor.