Lambda Sensor wires

[rodders850T5]

Just wanted to know which one of the four wires on the Lambda sensor whas the 0 to 1V signal on it (narrowband) I have 1 grey 1 black and 2 white.
Its for an air / fuel mixture gauge. The only other alternative is the ECU pin which has the Air/Fuel reading but dont have a clue on that either....cheers:stupid:

[iGGy]

The whites should be the heater part of the sensor. The black and grey go to the ECU.