Hi everyone, im back!
My name is Darius and im being very occupied with my stype lately as one might have noticed🤣. (3.0v6 2003)

P1647 is the matter tonight, ( faulty upstream o2 sensor on the LH side)

Firstly,
a quick test you can do to rule out the sensor itself, if you are faced with a similar problem:
Swap the upstream sensors in between them and delete the error.
- if the same error comes up, is not a sensor issue;
- if error moves with the sensor to the other bank, its the sensor.

In my case, the sensor is ok.
So i tested the harness from the ECU plug, to the sensor plug and i found out that one signal cable "N"ude/Brown (i've marked with red in the diagram below) appears to be interrupted.
There are no shorts & other cables were fine.

So i am trying to run another wire to replace the "N" wire BUT:

In the diagram, it appears to be an extra connection, that i marked with blue, to the exterior/insulation of both the sensor signal cables (the Nude one and the Green one)?

i have a spare harness that i took appart to see how it physically looks like and i posted a pictures below too.

So what is that extra connection?
If i run a parallel wire to replace the N wire, do i have to connect it there?

please help me as i want to do this repair right.
many thanks

 

See that oval where you added the blue question mark? The oval indicates a metallic shield covering those two wires.

The shield is usually a flexible braided sleeve, and is grounded at both ends. It protects the sensor circuit from electrical interference.

Typically the shield stops a few inches from the of the harness, leaving the two wires unprotected for that little bit. If the ground wire has broken from the shield, it’s not a big deal to trim the shield a bit and fabricate a longer ground to match.

You can carefully slit the sleeve and pull it off to the side. Twist the end and use an ordinary butt splice to join to the ground wire.

 

You are always so fast and kind to respond and help! I appreciate it a lot!

in my case i need to fix the nude (brown) wire

there is a spot where i can do a little surgery on the black insulation to expose the signal wires and therefore to expose the brown wire itself, right at the middle of the distance between the ECU plug and sensor plug. (its where the MAF plug comes out of the harness)

this way i can test continuity/resistance from the middle to both ends in order to see which side is the issue on.

i will then act accordingly, and keep you updated.

 

Update: solved

Even though I checked the wires entering the sensor plug, i've decided to do it again before i splice up the cable, and i found that the wire was ripped from its pin.

here is a little hack if you dont have an elevator, nor a tunnel:

Jack the car, remove the front wheel corresponding to the bad sensor side.
you will be able to acces the o2 sensor plugs from there. Its very tight tho.

i pushed the pin out by using a needle like screwdriver to unclip it. (each pin has a little hole at their roots)
I reestablished the connection and tested continuity. Works well now.

dont shoot new sensors at your car.
it might be the plugs