Ready to start wiring my 06 GM 3.5 I5 engine. Looking at schematics of wiring and wanting to take some sample readings with my meter under driving conditions. Wondering which signal wires to pick?...

These engine controls sensors are OBDII meaning 2- 02 sensors. Position one at the exhaust manifold (4 wire circuit) and position 2 further back in the exhaust pipe (4 wire circuit)...

Each ciruit position is the same wire layout except wire d...
a Ground
b High Signal
c Low Signal
*d Heater High Control on position 1 Heater low control on postion 2

Anyone have any experience with which is the one to tap?

Reasoning that I will need to tap into d on each to adjust high low balance of fuel mix ratio to ECN/PCM (Power Control Mod) but looking for expert opionins only

Thanks for looking
W

I don't know which wire, but my understanding is that on the 4 wire there are 2 grounds, 1 heater and 1 sensor wire. Here is what is says in d17.

Those sensors with 4 wires( the most common on current model cars), where there are
2 (slightly heavier) for the sensor heater,
1 for the signal, and
1 for the signal ground.

For the 3 and 4 wire sensors:
Disconnect the oxygen sensor wiring harness.
Set a multmeter to a DC voltage measurement range of a least 15 volts.
Turn on the ignition and probe the socket looking the two wires that provide 12 volts. These are the heater wires, so make a note of which they are,
Shut the ignition off, and reconnect eh oxygen sensor.

The two remaining wires will carry the sensor signal and ground..
Tap into these two wires, don’t cut yet..
Connect the DC voltmeter to the wires.
Start the engine and watch the meter readings.
If the reading is going negative, reverse the leads.
When the reading received are positive and going between 0 – .8 volts, the positive Lead is the sensor wire.

Hope this helps
Marlin

Normally the signal wire is gray. But, 2 of the wires should be identical in color - those are the heaters. Of the 2 remaining, one is usually stripped, the other ground. Shouldnt take long to get the correct wire.

Exactly....4 Wires have the Heater + and - . Then the Signal + and -...What you are thinking about is a Wide Band 5 Wire O2 sensor.

I just posted the PDF D17 in my Sales posting in the Energy Forum. Just go there and print it out. It goes through the whole procedure on "How to determine which wire is which" its very easy....

Oh well here you go....I will post it here also for others:

All,

Thanks for the valuable data...

Between this and a service manual schematic I should be good to go!

Then its time to decide wether or not I need to defeat the knock sensor on my intake sytem!

Blessings