Been getting P2270 code and check engine light turning on over and over.

(2006 Expedition XLT 4x4 5.4 nearing 170,000 miles)

Picked up a sensor the other day, but...
even after getting a box end wrench on the downstream sensor;
could not get it out.
Soaked with PB Blaster and WD40, added a little heat from torch, wouldn't budge.
Did not want to strip the hex off the sensor or wreck anything in case the new sensor was not the trouble.
Been applying more PB Blaster and WD40 each day now.
Hoping next weekend to try getting it out again.
Contemplating a pipe wrench if it does strip the hex.

Wondered if anyone had any tips for getting the stuck original sensor out and...

Anything besides replacing the sensor that might be needed?
I honestly have never needed to replace an O2 sensor ever before.
Been trying to search for other possible causes of the P2270 code but most seem to show replacing sensor fixing things.
Also wondered...
Is there such a thing as cleaning an old sensor. Saw a couple mentions of that.
Carb cleaner on business end of it??
I know the code is lean condition for the Bank 1 O2 sensor2, mine is downstream of the cat in what looks like a resonator.
Don't see or hear any exhaust leaks.
Have not seen anything else obvious either, and of course, runs fine.

Appreciate anything that might be of help.
THANKS

 

Replacing that sensor is a oneway street, getting the old one out without damaging it is a pretty big challenge, they get pretty stuck in there so once you get it out, toss the old sensor regardless if it fixes your problem or not.

 

Run the engine for a minute to warm up the exhaust pipe. This will expand the threads and loosen the grip it has on the sensor.

 

I remove O2 sensors using a rented tool that is a socket made for O2 sensor removal (from any parts store) and used a air impact gun and some times have had to use a torch to heat it to get them out.

 

Cannot believe how stuck this sensor is.
2 weeks+ of soaking it with WD 40 and PB Blaster daily and still no budge.
Code shows once a week or so but hasn't turned the dash light on in quite a while.
Not sure how much more effort I am going to put into replacing sensor since I am getting close to putting the Expedition up for sale.
I remembered my 95 Bronco earlier too...
When I upgraded exhaust I used a "diode" or something to keep the check engine light off after eliminating the downstream O2 sensor...started wondering if there was something similar for the Expedition, might be an easier fix if there was (well not really a fix, but...).

 

Well, the downstream sensors are only used to check the function of the cats. Not really needed, other than for passing inspection I guess. Depending on your location, it varies how strict this is. Where I live there's no inspection of this, nor requirements of having cats so when my cats bit the dust I simply removed the internals in the cats and welded a tube over the O2 sensors to fool them into showing good numbers for the cats. My sensors were still working though. If my sensors were removed or not working anymore, I'd just simulate the signal with a simple circuit. Again, depends on your location. I know in the US this would probably be very illegal...

 

No inspections here...that is why I wondering what it would take to "simulate a simple circuit" as you describe. I bought a little plug years ago for the Bronco. I will have to see if there is something like that for the Expedition...thanks ! ! !

 

Depends how savvy you are in electronics, but I believe there are wiring diagrams for making this yourself. You'd need a beefy resistor to simulate the heater circuit, then something to slowly oscillate the signal feed to the PCM, if I remember correct this only required a resistor and a capacitor.

 

Appreciate that too.
Pretty limited in my electronics knowledge but imagine I can find out what it takes and decide if worthwhile.
Thanks again

 

Well...
Finally took the time and got the old O2 sensor out.
What a PAIN ! ! !
Ended up with vise grips and a long pipe for leverage.
Had to heat the area around the sensor until I was afraid of melting something.
I could get about 1/4- 1/2 turn until having to heat everything up again.
About 3/4 of the sensors threads stayed in the pipe.
Ended up using a 3/8 NPT tap to clean out threads as best as I could.
I think the sensor was a metric thread but closet I had was what I used.
Ended up doing a good enough, close enough job to get the new sensor in.

BUT...
same code shows.
Disappointing but not unexpected.
Curious what the real issue is.
Runs and drives fine.
Since it is a lean condition code, I may try to replace fuel filter next.
If that doesn't remedy it, I order a capacitor and resistor that may just find their way into a couple wires on that pain to install sensor.
Seeing as I am going to sell the truck soon, I have already spent more time and effort than I would have liked.
Don't want to hand anyone a masked problem, but if it keeps light and codes off I will just tell them what has been done.
Again, thanks for all the help and advice.

 

You were working on the passenger downstream sensor, yes? Hate to hear you were on the wrong side....

STOP! You do not understand what that code actually represents. It does not have anything to do with how fuel is being metered for normal engine operation nor does it immediately relate to the operation of the converter. It's a pre-test of the catalyst-monitoring sensors before the normal catalyst tests can be performed.

 

As far as I know there is no passenger side sensor...
Crossover pipe brings exhaust together on drivers side.
Looked like the only downstream sensor was in what looks like a resonator.
I see two sensors before the cat on each side, but only one after is what I had been working on.
I thought the code referred to extra oxygen in the exhaust past the cats.
Saw exhaust leak letting outside air in or actual lean condition after the catalytic convertors.
If not...I am open and appreciate knowing what I am mistaken about.
Have been clearing the code and it keeps popping up same.
A day or two shows pending, then turns the engine light on dash on.
Without seeing an obvious exhaust leak or any other ideas to cause, thought maybe time for fuel filter that was restrictive and leaning things out...
otherwise thought of doing the sensor "simulator" mod with a capacitor and resistor.
Is there something else interferring with the test procedure???

THANKS !

 

There are 4 O2 sensors. Here is the location of the connector for Bank 1 Sensor 2.

 

Well...My code showed P2270 o2 sensor stuck Lean Bank 1 Sensor 2
Did not realize there was another...
Just my luck.
50/50 chance and this is what I choose
Will have to look at the other side now.
Thanks for straightening me out.

 

The downstream sensors are located mid-bed in each converter. The Y-pipe joins the two halves of the system together downstream of the two converters.