GEN 1 P0161 check engine light

[mike3605]

Hello all,

Haven't posted much here, but cant seem to find any info on this anywhere! I have a stock 2012 SCAB Raptor with 115k miles on it and I am getting a check engine light with code P0161 for 'O2 heater circuit Bank 2 Sensor 2'. I have changed the O2 sensor (even did Bank 1 Sensor 2!) but the light/ code will not go away.
For my own sanity, Bank 2 Sensor 2 is the driver's side downstream, correct? (on these trucks, the "downstream" seems to be located directly on the cat?)

I have a reader and have cleared the code, but it just keeps coming back! I even brought it to the Stealership to check it out, and they came to the same conclusion (replace bank 2, sensor 2 - which I already did!) and they wanted $417 for the O2 replacement ..... laughable.

Any insights?

I found this:

https://www.obd-codes.com/p0161

Replace HO2 Sensor
Repair open or short in power circuit
Repair open or short in ground circuit
Repair damaged connector due to tracking

Unclear how to chase wires or check a ground?

THANK YOU IN ADVANCE!

 

[risc]

Where'd you get the replacement sensor? Counterfeit parts are everywhere. You could try swapping bank 1 and bank 2 and see if the code follows the sensor.

 

[mike3605]

Where'd you get the replacement sensor? Counterfeit parts are everywhere. You could try swapping bank 1 and bank 2 and see if the code follows the sensor.

It's a Bosch - got it from AutoZone ... should be legit?

 

[Sozzy12]

Could take a couple drive cycles to clear. Did you clear the code then it came back? Jarheads... Lol

 

[MTF]

Is it a permanent code or pending?
You may just need to do a battery reset, meaning disconnect the ground terminal from the battery for 15 to 20 minutes.

A permanent code requires a PCM reflash.
There may be a way too clear a permanent without a reflash, you're going have to research.
Some have been able to get it cleared by a battery disconnect, cross your fingers. LOL
Most of us have a Tuner so it's easy to reflash without having to go to the dealer.

But the code suggests an open circuit so you may have damaged the wire to the O2.
It's a very thin wire and easily broken, it only monitors resistance and milliamps @ 0.5 volts
The replacement wire isn't to hard or expensive to replace.

 

[mike3605]

Could take a couple drive cycles to clear. Did you clear the code then it came back? Jarheads... Lol

Yes i cleared with my tuner

 

[mike3605]

Is it a permanent code or pending?
You may just need to do a battery reset, meaning disconnect the ground terminal from the battery for 15 to 20 minutes.

A permanent code requires a PCM reflash.
There may be a way too clear a permanent without a reflash, you're going have to research.
Some have been able to get it cleared by a battery disconnect, cross your fingers. LOL
Most of us have a Tuner so it's easy to reflash without having to go to the dealer.

But the code suggests an open circuit so you may have damaged the wire to the O2.
It's a very thin wire and easily broken, it only monitors resistance and milliamps @ 0.5 volts
The replacement wire isn't to hard or expensive to replace.

What wire would i need to check? I have a tuner ao i cleared the code. I will try the battery disconnect but i am not sure that will fix it since i clear the code with a diablo t1000

 

[MTF]

What wire would i need to check? I have a tuner ao i cleared the code. I will try the battery disconnect but i am not sure that will fix it since i clear the code with a diablo t1000

The wire from the O2.
There are four small wires inside, two are low voltage and two are the sensor wires.
You're using a Tune for your truck with a Diablo? Or just using it as a scanner?
And I did say that you need to reflash (return the truck to stock and reinstall the Tune) if it's a permanent code stored.
I don't know the diablo handheld device, but an Actron OBDII scanner will tell me if it's a pending or permanent code.
When three pending error codes happen in a row it sets a permanent.
And a battery reset may (and I stress may) remove the permanent code and you should be able to go three drive cycles.

But I think you have an electrical continuity problem not weak or bad O2s.
If you replaced the two rear O2s and the light still keeps coming on with the error code you posted,
then you need to move on to find the reason.
Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The next logical step would be to do a continuity test on the wires, right.

Car Corner: O2 Sensor Diagnostics - YouTube

 

[mike3605]

The wire from the O2.
There are four small wires inside, two are low voltage and two are the sensor wires.
You're using a Tune for your truck with a Diablo? Or just using it as a scanner?
And I did say that you need to reflash (return the truck to stock and reinstall the Tune) if it's a permanent code stored.
I don't know the diablo handheld device, but an Actron OBDII scanner will tell me if it's a pending or permanent code.
When three pending error codes happen in a row it sets a permanent.
And a battery reset may (and I stress may) remove the permanent code and you should be able to go three drive cycles.

But I think you have an electrical continuity problem not weak or bad O2s.
If you replaced the two rear O2s and the light still keeps coming on with the error code you posted,
then you need to move on to find the reason.
Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The next logical step would be to do a continuity test on the wires, right.

Car Corner: O2 Sensor Diagnostics - YouTube

I am just using it as a scanner only ... i will try the battery disconnect and then will have to wait a bit to get some help with a multimeter to chase the wire voltages ... will update with results. Thanks!

 

[raptorbone]

I'm having the same issue and have been for more than a year. Doesn't affect drivability but I can't get it inspected in TX.

I have done the same things as you. I also flashed the PCM, left for a week battery unplugged, and cleared the code with tuner. Code always comes back.

From the old O2 sensor, cut off the harness and connect to the truck's harness. Measure the DC voltage across the O2 sensor heating element leads. I believe it's the two white wires (please confirm; black and gray are for the sensor, I believe). Should read greater than 12V.

When I did this, I measured 12V on the passenger and 10V on the driver. Bad news...the O2 heater is driven by the PCM, not the fuse block. I still need to test continuity to the PCM through the harness. I think it may be a bad ground reducing the voltage. If not, I will have to go to the next step and replace the PCM. All over something that does nothing other than make the government happy.

Let us know what you find.