oxygen sensor vs

[Zipster]

Hi there,

I'm looking for the signal wire on my o2 sensors, I have a vs (v6 ecotec) and probed the four pins on the harness. Should I have normally 12v on the first one and under a volt for the other (wire 3 and 4 are ground apparently). In reality, my meter shows 0.7 on pin 1 and 0.4 on pin 2 (when engine running).

Is there a problem with the sensor itself or my approach is just wrong in the first place.

Anyone can tell me which of these 4 pins is the signal wire?

Thanks a dozen.

[The1]

on 4 wire o2 sensors, 2 wires will be earth, one will be 12v for the heater in the sensor and the other will be the sensor wire, the sensor wire should have around 400mv or .5volt with the key on.

[Zipster]

yeah got that. Problem is the first one has under a volt, is it ment to be like that? I was expecting about 12 if its he heater one. Do you know in what order they are ment to be knowing the earth are the 2 last ones? Is the signal wire the first one or the second? Is it normal that the heating pin shows under a volt?

Cheers

[The1]

Not sure which colour is what just unplug the sensor and measure each pin one should be 12volt one 0.5 volt and the other two earth.

You could also measure pins D13 for RH D15 LH sensor wires for 0.5volt
D14 and D16 are the earths at the ECU

I wouldn't worry about the heater 12v wires they might already be cut as the vs commodores had a earthing fault with the o2 heaters

EDIT: to actually test if the o2 sensors are working you need to hook up a multimeter and measure pins D13 for RH D15 LH sensor and while driving once warmed up the voltage should fluctuate up and down between 0 and 1 volt. Normally around the 300mv to 800mv. You will need a sensitive multimeter to pick it up.

[Zipster]

okay got that. Do you have a copy of the diagram to confirm the numbers you gave me?
Problem is that I DO NOT have 12v on any of the pins. I have one reading .7 and the other one is reading .4

[The1]

the 0.7 and 0.4 readings are within the normal limits for the o2 sensor signal wires, you just need to test if there fluctuating to see if your sensors are working. Shoot me a pm and ill email you a wiring diagram.

[kopper69]

http://www.memcals.com/pdf/VSV6%20Au...%20Diagram.pdf

This should help. Check for error codes if you think the sensors are out. Heater wont be on all the time I wouldnt think so 12V wont be there all the time.

[Not_An_Abba_Fan]

Once the car has been running for two minutes, the ECU cuts the power to the heater. The pink wire is the heater wire, the grey wire is the RH signal wire and the violet one is the LH. They are the colours in the loom on the ECU side of the plug, not the sensor side.

[Zipster]

Cheers mateys I'm onto it.