What causes a P0141 or similar O2 sensor heater circuit code?

[GitEmSteveDave]

I'm trying to figure out what is causing my O2 sensor trouble code. Since I had it replaced with a brand new NGK one, I'm wondering what "conditions" trigger the computer to throw a code? Is it measuring voltages? Is there a temp sensor on the O2 sensor that reports back what temp it's at? Could it's heater be functioning fine, but some other external force is stopping it from heating up as it should? Appreciate any input.

 

[LibertyTC]

What it means is that there is extensive resistance in the heating circuit of the 02 sensor.
How long ago did you install this sensor? Have you tried clearing the code to see if it comes back?

 

[GitEmSteveDave]

What it means is that there is extensive resistance in the heating circuit of the 02 sensor.
How long ago did you install this sensor? Have you tried clearing the code to see if it comes back?

Feb 26th. I had both bank 1 sensors changed with NGK's I supplied(My mechanic will not install customer parts unless they are quality), a oil sender replaced and an oil change. Codes were cleared by the mechanic and I tried it once myself.

That code appears EVERYDAY as a pending code since I had the engine replaced last August. I've tried swapping the relays, but it still appears: https://www.jeepkj.com/threads/oxygen-sensor-question.68072/ So I'm trying to figure out what triggers the code to source the problems. I can't go to my mechanic right now b/c he's an older guy, and I don't want to kill him unless it's neccesary, but I'm getting fed up hearing "Pending Fault Code Found p-0-1-4-1 o2 sensor Heater circuit, bank one sensor two" a minute after I start her up.

 

[LibertyTC]

I've seen many pending codes not trigger and engine light, is the engine light on/remain on?
Possibly the bank one sensor two, is not functioning correctly and should be warrantied out ?
I do believe there is a resistance test that can be done on that 02 sensor as well.

 

[Billwill]

You are going to have to climb into the Wiring Diagrams as I suggested...a bad wiring connection or a wire having worn its insulation through to engine/chassis somewhere.....these jeeps are getting old and wires shorting to ground or through to other random wires are becoming more common.

If you have a reasonable digital Multi Meter I can direct you through the process via the Wiring Diagrams....not always easy as while measuring the wires you move them slightly and the bug dissapears

 

[Phuc Nguyen]

I'm trying to figure out what is causing my O2 sensor trouble code. Since I had it replaced with a brand new NGK one, I'm wondering what "conditions" trigger the computer to throw a code? Is it measuring voltages? Is there a temp sensor on the O2 sensor that reports back what temp it's at? Could it's heater be functioning fine, but some other external force is stopping it from heating up as it should? Appreciate any input.

I replaced mine about five months ago, and noticed the color of the wires between the new and old sensors were not matched at connector.
They are very easily removed and repositioned to mathched, if you still have the old one laying around. Just remove a small clip and all the wires are free to remove without any force.

BTW, I usually keep my old parts in a stash bin just in case I cannot solve the issue.

Hope this will help solve your trouble code.

 

[jeepguy4276]

Mine throws the code only if I maintain an rpm much higher than idle when the engine is really cold. Once the engine warms up it goes off. I’ve only noticed it in the winter when it’s really cold out and I don’t give it time to get warmed up before I hit the highway. Then it goes off itself. If I let it warm up there’s no issue. All my O2 sensors are new NGK and all the wiring is in good shape.

 

[GitEmSteveDave]

You are going to have to climb into the Wiring Diagrams as I suggested...a bad wiring connection or a wire having worn its insulation through to engine/chassis somewhere.....these jeeps are getting old and wires shorting to ground or through to other random wires are becoming more common.

If you have a reasonable digital Multi Meter I can direct you through the process via the Wiring Diagrams....not always easy as while measuring the wires you move them slightly and the bug dissapears

Yeah, before I set my mechanic loose on it, I wanted to make sure that it has to be triggered by an electrical problem and not something like a cracked pipe/weld that lets outside air in and prevents the sensor from heating up or some nonsense. That really solidifies my idea that when they put the new engine in, the wiring might have gotten damaged.

 

[GitEmSteveDave]

I replaced mine about five months ago, and noticed the color of the wires between the new and old sensors were not matched at connector.
They are very easily removed and repositioned to mathched, if you still have the old one laying around. Just remove a small clip and all the wires are free to remove without any force.

BTW, I usually keep my old parts in a stash bin just in case I cannot solve the issue.

Hope this will help solve your trouble code.

Don't have the part and the mechanic thought it was fixed, but while we were settling up, Lippy Libby started reading out the pending code from my pocket after I hooked the bluetooth adapter back up. I usually drop her off before work and either walk to work or catch a ride and then pick her up at the end of the day.

 

[LibertyTC]

For the heater circuit I thought I would throw this in.
Not the best video, but it gives you an idea how to test the 02 sensor/circuit.

xc_hide_links_from_guests_guests_error_hide_media

 

[GitEmSteveDave]

So I was super excited that earlier this year, the "Emissions & DTS" panel on Torque Pro went from "Incomplete" to "Complete" in Re: Heater circuits, which meant I might have a chance at State Inspection. But Covid was still around and many DMV offices and facilities were closed. Then one night, while driving in the rain, a CEL came on from high voltage on another sensor and it was lost.

A few months later, it cleared again, somehow, but while at my polling place, my battery got too low listening to the radio and charging my phone to look up more info about state ballot questions, so it was lost again.

Since I had never changed the wiring, there must be a way to "fool" the system into thinking that the heater circuit was working, because it's not checking the sensor itself for temp, otherwise it never would have went to "complete" and using torque, I can see live readings from the sensor, so I know the sensor works. That was the key into figuring out what triggers the O2 sensor heater circuit code.

It's not resistance or continuity, it's how quick it takes to start registering a voltage other than 1volt, which requires heat. So the other night when I got out of work, I just kept the engine revving ~2k rpm , so it was sending hot exhaust the whole time, heating up everything on the exhaust system, and the Sensor 2 on Bank one was just about 10 seconds behind Sensor 2 on Bank 2 at registering a voltage as I was driving down the road. Lo and Behold, NO pending CEL/DTC. I went to grab some food at the supermarket and when I left, I did the same thing, pulled out quick, went straight to a main road and got up to highway speed and I watched as the heater circuit went from "Incomplete" to "Complete" and no pending codes were shown on Torque.

Gonna do it again tomorrow and go straight to the inspection station, as I'm 9 months overdue now.