P2238

[nofear6235]

Hello all. I am an original owner 2008 SR5 V6 with 129k miles on it.
Some time ago I got P2238 and after extensive research and using my OBDII reader I came to conclusion (i am not sure of it) it's faulty upstream AF sensor on bank 1 (passenger side).
Before ordering and replacing the sensor I looked at freeze and live frames from OBDII reader and wanted to ask people to confirm that it's in fact or at least a large chance to be the upstream sensor on bank 1 as it displayed next to the code on my OBDII tool.
I will post some pictures with data from reader..
Also I can't find any thread with pictures to how get it out. From bottom or side or top of the truck and what tools to use. It would help tremendously since it does looks like big pita to get to sensor and it's connector
Here some pictures live and freeze frames.
Right of the bat, what got my attention:
From Live data
FUELSYS1 OL_Fault not close circuit? AF sensor not recognized?
FUELSYS2 OL_Fault
SHRTFT1 and FT2 is 0 no fuel correction done for short trim fuel? ??
LONGFT1 3.9
LONGFT2 29.7 why so much difference between banks?
MAF sensor numbers seems fine
From Freeze Frame:
02B1S1 (3.296 V) almost 3.3 that is correct number.. when I increase the throttle during live run, the number go a bit down, not up as it should if the car running lean, yes?
and Short and Long fuel trim in freeze frame is completely different values comparing to Live Data
I hope someone who knows can put me on the right direction.
Thank you in advance.
Alex

 

[Ralph Blake]

Is the truck having problems like fuel mpg dropping or rough running? if not why worry? but if it's keeping you up at night spend the money and replace it.

 

[nofear6235]

Is the truck having problems like fuel mpg dropping or rough running? if not why worry? but if it's keeping you up at night spend the money and replace it.

It is actually keeping me up at night.
It does run rough, mostly during the throttle. Not so much during acceleration but mostly when I release the accelerator pedal. I hear some unusual sound, kind of raspy, coming either from engine or cats or somewhere..
We drive this truck all over the North East and I don't want to damage anything if it runs lean or something like this.
I have no issue to replace the part, I want to make sure it is in fact what needs to be replaced, and it's a nature for my question.

 

[Ralph Blake]

It is actually keeping me up at night:frisky:
It does run rough, mostly during the throttle. Not so much during acceleration but mostly when I release the accelerator pedal. I hear some unusual sound, kind of raspy, coming either from engine or cats or somewhere..
We drive this truck all over the North East and I don't want to damage anything if it rans lean or something like this

I would try finding someone "not the dealer" to run some real tests with really quality scanners, it would be worth paying for someone who really understood the problem.

A major problem i have noticed lately and i did not know it existed, is when an O2 Sensor is sending a wrong signal to the fuel injector's to add more fuel then is required for the existing conditions, it causes the clogging up of the Cats and this causes rough running of engine and is a real problem to get the Cats cleaned.
If they must be replaced your looking at thousands for new Cats and a high price to replace them, and you still have to find the problem sensor and replace it.

 

[nofear6235]

I would try finding someone "not the dealer" to run some real tests with really quality scanners, it would be worth paying for someone who really understood the problem.

A major problem i have noticed lately and i did not know it existed, is when an O2 Sensor is sending a wrong signal to the fuel injector's to add more fuel then is required for the existing conditions, it causes the clogging up of the Cats and this causes rough running of engine and is a real problem to get the Cats cleaned.
If they must be replaced your looking at thousands for new Cats and a high price to replace them, and you still have to find the problem sensor and replace it.

Good to know. I hope it's not the case with cats yet. But will see.
Thank you for reply.
Alex

 

[djpope09]

Best guess for these LTFT readings (fuel trims)

This thread might help you. It mentions that Long term fuel trim > 10% is a problem. Your pictures show LongFT2 (%) of 29.2 and 31.3. Since your long term FT1 is in a good range, you could swap the driver side upstream A/F sensor to the passenger side and vice versa. Then see if the LongFT1 changes to ~30% and the LongFT2 changes to <5%. That would confirm if the A/F sensor needs to be replaced.

I was able to get to both upstream sensors from the top, the driver's side is a little harder to get out. I used a ratchet and an O2 sensor socket. A flex-head ratchet would be helpful.

 

[nofear6235]

Best guess for these LTFT readings (fuel trims)

This thread might help you. It mentions that Long term fuel trim > 10% is a problem. Your pictures show LongFT2 (%) of 29.2 and 31.3. Since your long term FT1 is in a good range, you could swap the driver side upstream A/F sensor to the passenger side and vice versa. Then see if the LongFT1 changes to ~30% and the LongFT2 changes to <5%. That would confirm if the A/F sensor needs to be replaced.

I was able to get to both upstream sensors from the top, the driver's side is a little harder to get out. I used a ratchet and an O2 sensor socket. A flex-head ratchet would be helpful.

Thanks DJ, its helpful, I appreciate your reply!
I've been thinking to swap the upstrram sensors before, but because it's not an easy task and considering the truck has almost 130K miles, and the error code pointing specificly to Upstream AF sensor bank 1 , I will get Denso passenger side AF sensor and replace it first. It will be my next step and I'll see what will happen next. I'll get this issue resolve sooner or later. Will do it gradually and organized, step by step. Already started PB blasting, let it soak until Denso arrive
Is it possible you can snap picture of the tool set up you used to get sensor out?
And what needs to be remove to get to the passenger side sensor and connector easier? I noticed the connector is hidden between the plastic intake and firewall..
Thanks again man.
Alex

 

[djpope09]

I don't have a picture of the tool, but it's like this:
Amazon.com: KAX 3/8-Inch Drive, 7/8-Inch (22 mm) Offset Oxygen Sensor Socket, Wire Gate Accesses O2 Sensor from the Side, O2 Sensor Socket Prevents Damage to Wires, All Vehicle O2 Sensor Removal and Installation : Automotive

I don't think you need to remove anything on the passenger side to get to that one. A cheater bar helps if you have a small one, there's not much room to push or pull.

If you have to do the driver's side, it's a lot tighter, but you shouldn't need to remove anything.

This video shows a good way to do it with the two wrench method for extra leverage. I would try that first next time, might save you from having to buy the special socket.
https://www.youtube.com/watch?v=UJAEjy223Yo

 

[nofear6235]

I don't have a picture of the tool, but it's like this:
Amazon.com: KAX 3/8-Inch Drive, 7/8-Inch (22 mm) Offset Oxygen Sensor Socket, Wire Gate Accesses O2 Sensor from the Side, O2 Sensor Socket Prevents Damage to Wires, All Vehicle O2 Sensor Removal and Installation : Automotive

I don't think you need to remove anything on the passenger side to get to that one. A cheater bar helps if you have a small one, there's not much room to push or pull.

If you have to do the driver's side, it's a lot tighter, but you shouldn't need to remove anything.

This video shows a good way to do it with the two wrench method for extra leverage. I would try that first next time, might save you from having to buy the special socket.
https://www.youtube.com/watch?v=UJAEjy223Yo

Again, thank you for reply. Appreciate. I saw this video before.
I already ordered similar socket and flex tool along with both upstream sensors for bank1 and 2 from RockAuto, should be here any day.
I agree, it does looks possible to get the sensor from the top, but to get to connectors , oh man! I removed the rubber shield from behind the pass wheel, may be I can get to connector from there.
My truck story is not getting any less confusing, I just don't want to list all live and freeze data again, but it is very different every day I check! I no longer have OL FUEL error on any of the banks, code went off by itself from the dash board yesterday but it's still show on OBD tool, in stored and pending and now with new, additional p0174 (system too lean BANK2).
I again checked my air filter box, replaced the filter, clean MAF once again, look to any sign of vacuum leak, etc.. All legit..
The car idle perfect, drives okay too, until I release accelerator pedal and I hear that unusual, kind of raspy sound from the engine or cats, or who knows where..
Other than this is no issues.
The only difference I noticed now, that MAF shows huge numbers when I rise the idle or especially drive, I believe it's wrong , to have over 10 g/sec while checking live map on OBD.
Lastly it is always the chance that noise I hearing while driving is unrelated to these codes, but I doubt, I think it is.
I am out F%^ Pain.. Should be million miles club truck, lol
I'll research more, thank you for reading.
Alex

 

[nofear6235]

Again, thank you for reply. Appreciate. I saw this video before.
I already ordered similar socket and flex tool along with both upstream sensors for bank1 and 2 from RockAuto, should be here any day.
I agree, it does looks possible to get the sensor from the top, but to get to connectors , oh man! I removed the rubber shield from behind the pass wheel, may be I can get to connector from there.
My truck story is not getting any less confusing, I just don't want to list all live and freeze data again, but it is very different every day I check! I no longer have OL FUEL error on any of the banks, code went off by itself from the dash board yesterday but it's still show on OBD tool, in stored and pending and now with new, additional p0174 (system too lean BANK2).
I again checked my air filter box, replaced the filter, clean MAF once again, look to any sign of vacuum leak, etc.. All legit..
The car idle perfect, drives okay too, until I release accelerator pedal and I hear that unusual, kind of raspy sound from the engine or cats, or who knows where..
Other than this is no issues.
The only difference I noticed now, that MAF shows huge numbers when I rise the idle or especially drive, I believe it's wrong , to have over 10 g/sec while checking live map on OBD.
Lastly it is always the chance that noise I hearing while driving is unrelated to these codes, but I doubt, I think it is.
I am out F%^ Pain.. Should be million miles club truck, lol
I'll research more, thank you for reading.
Alex

Alright, here is an update:
I learn so much more about my rig issue between the first post of this thread and today.
My finding may help someone in the future..
Here we go:
Tried different MAF from my friend truck, no changes. Wasn't the issue in this case.
Replaced passenger side upstream AF sensor (on my own) with new Denso from RockAuto, cleared P2238 about a week ago, so far code did not came back.
Next I replaced driver side upstream AF sensor also with new Denso (fyi, bank 1 and bank 2 AF sensors are the same part number).. Also, i spent few hours and wasn't able to removed that rusty b#$ach so I went to local Midas shop and let them do it for $70 in front of me, to make sure they put copper grease that comes with the sensor on its threads. Cleared P0174 and so far it did not come back for last 3 days. The fuel trim improved and I think it's where it should be now.
So I am happy with this part, but I do still have this unusual noise from time to time when I accelerate and release the gas pedal. Its hard to describe, kind of pronouncing howling on specific speed, most heard between 30 and 40 mph.. I though may be transmission, but when put and roll on neutral sound does not change at all. I will check the fluid level though to make sure its good..
What I am worry about it's a driver side catalytic converter. I have a bit of feeling this sound coming from there after I saw my old AF sensor that I removed, it's all black,dirty and smell gas. May be for the time I drove with P0174 (about a month before I got the fix) it damaged driver side cat.. I hope I am wrong..Big job..
My next step is to test this cat with my OBDII reader (check the voltage in INLET and OUTLET and check the temp in the front and end of this cat with infrared thermometer. I saw great YouTube video on how to do that).
I'll let you know guys
Alex
p.s. Here is my new OBDII data after replacing these upstream sensors..