So I bought a new set of front/rear o2 sensors and Y pipe recently. Got everything back together and received a o2 code, something do to no signal. I checked the live data and realized that one of my rear o2 sensors, with the key on, is NOT reading .450 volts like the others 3 are. It is reading in the range of (.000 to .010). I swap sensors on the rear with the other rear one and i get the same issue on the same side.

So the sensors are fine, and I figure there is a wiring issue. Am I in the right assumption here? Is there a good way to check the wiring with the meter? Which color wire should i check?

Also, both rear o2 sensors are heating up, so the heater circuit is working.... so it seems to be the return voltage reading at the ecu?

I did have a wiring issue with the Front o2 sensor, on the same side, that had been previously rigged by previous owners, and I spliced in the correct harness clip to the same color of wires. I doubt this would cause an issue, but i figured I'd add that.

Also, when I leave the connector in question unplugged from the sensor, my reading goes to .450.

Thanks again!

 

Man, if you can figure that one out I would be very interested in what you did. I bought mine with a few codes and got them all to go away but P1170. I have a new Magnaflow wye pipe and changed sensors twice and the drivers down stream 3 times thinking it was a bad Amazon sensor. Mine starts up in the loop mode until heated up and then the B1S2 starts it's slow decline to 0. When I swapped the engine we went through the loom, no issue. I now have a new ECM ready for reprogramming. Does not effect operation just annoys me to see it coming...

 

So after some investigation, I looked at the harness and came across some black electrical tape with a large pump in it. So I pealed the tape back to find the wires like this. The weird thing is, this damaged harness goes to the passenger side. Aka Bank 2. Both of my scanners say the voltage reading error is Bank 1.

This car has had work done to it before by some shade tree mechanics. Is it possible they routed the harness the incorrect way? How is the harness supposed to be routed? I added a picture to explain what I mean. I can't find a good diagram in the rave. At the current moment, it is routed like A.

 

Mine is routed like A, wire loom comes down the drivers side corner of the engine bay and clips along the way until it gets to the left rear sensor and then the loom crosses over and connects to the passenger rear sensor. Did that red/stripe wire break when you took it apart or???

 

When I took the tape off carefully, it had already been broken and was underneath the tape, no where NEAR the butt connector....I will up date with the results tomorrow after i fix it.

 

Oh that picture, that would upset me.

 

Crimping is actually the correct way to splice O2 wires. I would just re-crimp them and put some heat shrink over the whole deal.

 

Rear o2 sensors are working great now, after the fix. But I am now getting a check engine code p0134. Bank one, sensor one. I am getting very minimal voltage change(it is sticking around .445-.460). I double checked the wiring connection that I previously repaired and everything is tight/secure/correctly matched. What signal should i be looking for and where?

Edit. I also swapped with the other front sensor AND another new Bosch sensor from advance auto. Same results....

 

Another thread was just talking about the bosch sensors. As i said there, i went thru 4 bosch front O2's, all from amazon. Finally gave up on them and bought Walker from AB Land Rover Oxygen Sensor Replacement (Same Fit As Part # 250-24496)
So far so good.

 

That is possible. But I have a working one on the other side. Swapped them and the "Bad side" sensor is working and showing a signal on the good side.