Air/fuel Ratio Gauge Install

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Junior Member
i have a EK CIVIC hB with its stock D16Y7 with its obdII P2E ecu..

i would like to know the pin outs of an OBDII 4 wire oxygen sensor? There are two (2) black wires, light green wire and a white wire.

Can anyone tell me to which of these wires i hook up the Air Fuel ratio Gauge?

And in which of the 2 O2 sensors; primary or secondary?

thanks in advance... :)
i would put it in the primary O2 sensor and the two black wires are heaters... i would connect the A/f gauge down by the ECU rather than in the engine bay as well.

i connected mine to the white wire.
4 wire o2 sensor as follows:

one wire to ecu, primary signal,
one wire to ecu ground,
one heater wire to ecu
one heater wire to battery (via fused connector)

This sensor should be on all civic's obd1 and obd2 from 1992-2001