[808celicagt]

Originally Posted by Pineapple

1 Wire O2 - easy, don't even ask :P
2 Wire O2 - One is signal, one is ground. Use a ohm meter to find the ground.
3,4 Wire - 1 signal, 1 heater power, 1/2 ground. Ohm meter to find ground, volt meter to find +12V heater with ignition on. Don't knoe if you need to start the engine.
A good gauge should be high resistanct which means it won't affect the signal. It doesn't matter where you tap the wire. Easier to find wire on the sensor, no need to drill hole on ECU. You'll need wiring diagram to tap on ECU.

ok. thanks for the info