O2 Sensor help

[vyseriesII]

Hey all,

There are 4 wires coming out of each of the exhaust o2 sensor at collector into a 4 pin plug. I need help to find out wat each wire is, particulary the wire that is sending the varried readings to the ECU. Each plug appears to have 2 white wires a black and a grey. Iv'e tried finding wiring diagrams but with not much luck.

Any assistance is appreciated

[Tree cutter]

The white wires will be earths. One for the heater and one for the sensor. My manual shows the other wires as pink and grey. Pink is supply voltage and grey is signal to ECU

[vyseriesII]

Cheers Tree Cutter