2002-2006 RSX Primary O2 Sensor Wideband Info:
The 4 wires on the Primary O2 need to go to:
1 – Primary O2 Signal (+) (white / red on my harness)
Continuity to C101 pin 19, from there the wire goes back over to ecu A6 where it delivers signal info to the ecu.
2 – Primary O2 Ground (-) (green / blue on my harness)
Continuity to C101 pin 13, from there the wire goes over to ecu A16 which is a sensor ground.
3 – Primary O2 Heater Signal (+) (yellow / black on my harness)
Continuity to C101 pin 15 (from there the wire goes over to ecu A22)
*NOTE: This wire is also divided and is tied into a relay. I will add the relay information a little later.
4 – Primary O2 Heater Ground (-) (orange / blue on my harness)
Continuity to C101 pin 10 (from there the wire goes over to ecu pin A1)
However In some swap harnesses I have seen this wire pinned directly to K-series ecu pin E4. That also works as an appropriate heater ground.
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2005 RSX Primary O2 Info
The 4 wires on the Primary O2 need to go to:
1 – Primary O2 Signal (+) goes back over to ecu A31 where it delivers signal info to the ecu.
2 – Primary O2 Ground (-) goes over to ecu A28 which is a AFR Sensor sensor ground.
3 – Primary O2 Heater Signal (+) goes over to the heater circuit relay (custom) which should turn based on output from pin E8. Some swaps ignore this an try to power from E8 directly, this could work but can also cause issues.
4 – Primary O2 Heater Ground (-) goes over to ecu pin A10.
References:
Info and pic from: https://www.k20a.org