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Discussion Starter · #1 ·
I have owned my 2005 SE Toyota Tundra since August of 2008. Since then, I have had non-stop issues with it; the check engine light comes on at least once a week.

There is almost 90,000 miles on my truck. I have taken it to my Toyota Specialist twice when the light has gone on and it has come up with teh P0172 code. He has fixed the issue, both times, by replacing the air fuel sensors in bank one and two. This has NOT been a cheap fix! Apparently there are 2 more sensors behind the cadalidic converter, but they aren't as prone to go out as the front 2 are.

So, a week later, the light goes on after I gas up. Two days later, I tighten the gas cap (after reading some threads about how that tends to set off the check engine light) and it goes off. Well, it went on again today. I tighten the gas cap (I gassed up 2 days ago), and it stays on. I take it to AutoZone and they run a diagnostic and the P0172 code comes up. The issues is stated as this :

Definition: fuel trim bank one condition

Explanation: The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio of the engine. THe computer has recognized a rich or lean condition on one engine bank only.

Probable Causes:
1. If bank one and two codes set together suspect fues pressure or MAF (Mass Air Flow) Sensor
2. Oxygen sensor defective
3. Ignition misfire-repair
4. Fuel injector problem

So, the guy gives me two bottles of fuel and injector cleaner, tells me to put one in now, let my tank run dry, then put the second in before I gas up (I already use premium gas). He suggested I wait a week or two before I take it in to get looked at... if the light hasn't gone off by then, I should definitely take it in.

My frustration is this: I bought this truck to pull my horse trailer. I understand that normal wear and tear starts to occur at 100,000 miles... but I've had non-stop issues with this truck since I first got it. I do not want to have to be paying for SOMEONE ELSE'S wear and tear on the truck! The dealership I got this truck from is ridiculous. The BBB has already been contacted on them NUMEROUS times... not to mention the 4 salesmen/managers who sold me my truck were fired...

So, I'm at a loss at what to do. I love my truck, but I don't want to keep putting more money into it (which I am running off of a teacher's salary and money is very limited!) if I'm never going to get a postive outcome on this truck in the long run! I'm getting closer and closer to trading it in...

If anyone has any suggestions or dealt with this issue, please help! My already short patience is really being tested...

Much thanks ahead of time!
 

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the first thing some mechanics will say is to (replace the 02 sensor) this is incorrect in this case, the 02 sensor is working, its telling you have a rich condition on bank 1 (driverside) of the engine.

with out going into detail here, some items to check are

1. air filter is it dirty
2. injectors pluged?
3. mass air flow meter, is it dirty?
4. engine temp sensor or thermostat stuck
5. fuel pressure too low or high
6. and even an exhaust leak will cause this code


my opinion spend the money and have the toyota dealer check it...

hope this helps
 

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2015 Toyota Tundra DC SR5 5.7L
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the first thing some mechanics will say is to (replace the 02 sensor) this is incorrect in this case, the 02 sensor is working, its telling you have a rich condition on bank 1 (driverside) of the engine.
No, the air-fuel sensor isn't "telling" anything. The ECU is generating a fault code for the given conditions (which it concludes from it's limited database to be a too rich mixture, Bank 1), and you are doing the OP a disservice by jumping to the conclusion you did. You are inferring a definitive conclusion based on a string of disparate data points. The only thing you know for a fact is that the CEL code read was P0172. This could mean many things, one of which is a failed O2 sensor.

The OP's mileage supports the argument that the O2 sensor group may be the culprit. 90K-100K miles is the expected life span of the heated air-fuel/oxygen sensors used in our Tundras. My first question is whether the sensors replaced are OEM Densos or aftermarket. Invariably on here, we hear about someone who had a sensor (or two) replaced and the same code popped right back up again. Turns out the service tech installed a Non-OEM, other-brand, or aftermarket unit. It was cleared up by replacing with the correct Denso unit.

There can be other issues here, i.e. exhaust leak, dirty MAF, injector issues, etc. If it was MY truck, I'd make sure to replace both sides of the affected bank with OEM Denso units, clear the code, and see if that solves it. If it doesn't, at least you know you have new sensor units in there and can look elsewhere for a systemic issue, which are way harder to find.
 

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I myself would follow what toyota says, they make the vehicle.

The only disservice is telling someone to change parts that may not need to be replaced, the only way to know whats wrong is connect a scan tool to the truck and look at the readings in real time.

Or if you have money to just burn, replace parts at will and hope you get the right one's, with o2 sensors running about $150.00 each I myself if I did not have a scan tool would take it to the dealer and spend 80 bucks for an accurate diagnosis and replace the correct part or parts rather then guess.

For very little money you can check the air filter, clean or replace if need be, remove and clean the mass air flow meter, use a bottle of injector cleaner and see if it helps, look at the temp guage, is it about half way up when hot? this is of course for the person who does not have access to a good hand held..

this is all basic stuff that can be done at home for very little money before assuming on an o2 sensors that were both replaced already.

P0172
P0175
When air−fuel ratio feedback is stable after warming up the
engine, fuel trim is considered to be in error on RICH side
(2 trip detection logic)
 Injector leak, blockage
 Mass air flow meter
 Engine coolant temperature sensor
 Ignition system
 Fuel pressure
 Gas leakage in exhaust system
 Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit
 Heated oxygen sensor (bank 1, 2 sensor 1)
ECM

http://www.ncttora.com/fsm/04-06-Tu...ypdf/06rmsrc/06tundra/di/eg1grfe/cip01711.pdf
 

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2015 Toyota Tundra DC SR5 5.7L
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Super Moderator
2015 Toyota Tundra DC SR5 5.7L
Joined
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8,559 Posts
I myself would follow what toyota says, they make the vehicle.

The only disservice is telling someone to change parts that may not need to be replaced, the only way to know whats wrong is connect a scan tool to the truck and look at the readings in real time.

Or if you have money to just burn, replace parts at will and hope you get the right one's, with o2 sensors running about $150.00 each I myself if I did not have a scan tool would take it to the dealer and spend 80 bucks for an accurate diagnosis and replace the correct part or parts rather then guess.
As I mentioned, he has almost 90,000 miles on the vehicle already. He is approaching expected life of the O2 sensor units. It is a given that the easily fixed items (MAF cleaned, throttle body plate cleaned, air filter cleaned/replaced, spark plugs checked, etc.) should be done ANYWAY.

You suggest spending $80 to just drive into the service bay, not to mention the cost associated with letting the service techs stumble around trying to find out the problem. Yeah, they are not averse to guessing too my friend.

These codes pop up for members with higher (90K+) miles on here all the time, and have been fixed by new sensors, a little anti-seize, and a little time under their truck. And NO infuriating back-and-forths with their dealer's service writers. If the OP's mileage was far less, then I would hesitate to suggest a simple R/R on the sensor package.

OEM Denso Bank 1 sensors can be had for $60 each. I suggested spending $120 and replace both bank 1 units. If there is still an issue, then you know that your components are operating normally, and you can further narrow your search parameters.

Where is the OP? Is he going to give us an update?
 

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Well maybe I just have a great mechanic at my dealership, if it's something I cant do, it goes to the dealer only.

My experence is a 1yr, 12000 mile warranty at the dealer rather than a 30 day warranty on parts and no labor warranty at the independent guys here.

Also noted is in most cases here, the dealer is cheaper than the independent shops around and do a better job.

however I have never used a dealer in another state.

plus im a cheap bastard :)
 

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2015 Toyota Tundra DC SR5 5.7L
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Well maybe I just have a great mechanic at my dealership, if it's something I cant do, it goes to the dealer only.

My experence is a 1yr, 12000 mile warranty at the dealer rather than a 30 day warranty on parts and no labor warranty at the independent guys here.

Also noted is in most cases here, the dealer is cheaper than the independent shops around and do a better job.

however I have never used a dealer in another state.

plus im a cheap bastard :)
You're one of the lucky ones. I have a pretty decent Toyota service department at my dealer here as well.

I've found that the secret is to choose which tasks to have the dealer do and which ones that any independent shop can do for a lot less. Under strict supervision that is!

O2 sensor issues get quite a bit of coverage on this forum and I have yet to see a situation where the O2 sensor wasn't the failing component in the equation. Either that, or it was replaced with a brand new Bosch part and they still couldn't figure out why the same CEL code was back again. Maybe it's just a function of the miles on the trucks that get posted here, I dunno..

The O2 sensor replacement job is pretty straightforward. I recently posted a DIY with parts links here: http://www.tundrasolutions.com/forums/1197269-post2/
 

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I have heard bad things about bosch parts and toyota's, i have never needed to replace any sensors on my toyota's yet and if i do, it wont be with bosch...
 

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Discussion Starter · #11 ·
Ok... for starters, I'm a female!

I used fuel injection cleaner and the light went off. However, just got to almost an empty tank and the light came back on. The only parts that are put in my truck are certified Toyota parts so I know they're not using aftermarket... I plan on taking it to my Toyota Specialist next week. Being that both banks have been replaced, I'm guessing that it may be the O2... or maybe something else?
 
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