The O2 Wiring page is where the O2 Control function gets its sensor input. Before assigning anything, know which kind of sensor you have, because they work very differently.
- Narrowband: the factory-style sensor. It produces roughly 0 to 1 volt and really only tells rich from lean around stoichiometric. It's fine for emissions-style cruise control, and the narrowband target voltage setting is built around it. See narrowband O2 sensors.
- Wideband: reads an actual lambda value across the whole range, so it's what you want for tuning. Haltech's WB1 CAN wideband kit sends its reading over CAN. See wideband O2.
Whichever you use, confirm the reading is sensible in NSP with the engine warm before you enable closed loop. Also check the sensor sits upstream of the catalytic converter with no exhaust leaks ahead of it, since a leak pulls in air and makes the sensor read lean. Once the signal is trustworthy, long term fuel trim can build on it. Unsure how to wire yours? Ask us.
