CEL: The Engine control system has reached its adaptive learning limits with the fuel control system.

[shurmanter]

You would get this code if you put E85 (85% ethanol) in the tank. MPG would also go down by 30%. But maybe 10-15% if you only added half a tank.

The nice thing is, it will all return to normal once you use it up and put in stronger gas.

Definitely wasn’t labeled as E85. Tbh I’ve never actually see that at a station as I don’t think that’s a thing up here in Massachusetts.

I DID fill up yesterday though…

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[shurmanter]

Probably not but on the more dangerous end could be a leaky injector or fuel line issue. I would definitely give it a good sniff under the hood for fuel smells and get it to the dealer soon.

I was looking under good yesterday and didn’t smell anything

 

[NeedForSteve]

being this new, I'd lean toward something inducing a vacuum leak, like maybe a faulty CPV. If you're still under warranty there's no reason to futz around with it yourself. Take it in and let them document the issue.

 

[shurmanter]

being this new, I'd lean toward something inducing a vacuum leak, like maybe a faulty CPV. If you're still under warranty there's no reason to futz around with it yourself. Take it in and let them document the issue.

Absolutely is my plan. Just wasn’t sure if others had seen this could help me help point them in the right direction. No idea about a loaner from then and I need a vehicle, so time is limited.

 

[VBMav]

Would the computer report something like this if the fuel "cap" didn't close all the way? This would prevent the hybrid fuel tank from pressurizing fully from what I understand.

 

[GPSMan]

Would the computer report something like this if the fuel "cap" didn't close all the way? This would prevent the hybrid fuel tank from pressurizing fully from what I understand.

Different code.

 

[Ozarkbeard]

I DID fill up yesterday though…

That fact would've been good to put in your original post.

I've had CELs come on after filling up with "suspect" gas. Make sure you fill up with "Top Tier" fuel. And if you have it, try using what we call "real gas" around here. It is ethanol-free and usually pricier. However yesterday, it was down to $2.49 at a station near me. So I'ma switch to it for winter driving. Regular 10% ethanol fuel is down to $2.35

 

[shurmanter]

That fact would've been good to put in your original post.

I've had CELs come on after filling up with "suspect" gas. Make sure you fill up with "Top Tier" fuel. And if you have it, try using what we call "real gas" around here. It is ethanol-free and usually pricier. However yesterday, it was down to $2.49 at a station near me. So I'ma switch to it for winter driving. Regular 10% ethanol fuel is down to $2.35

Yeah. Prices are still over 3 here.

I totally get your sentiment about the fillup and certainly could be contributing but I did notice previous tank was lower mpg than is typical, so wasn’t thinking it was that.

 

[MakinDoForNow]

P0171 System too lean bank 1. Any ideas about this.

TSB. 23E07 is software update for oxygen sensor to fix possibility of running with non optimum efficiency. At least that's what my recall notice said
Reread notice "heating element used to warmup emissions control sensor is not working due to a software error".

 

[Maverickman74]

I was looking under good yesterday and didn’t smell anything

Well thats good. You never know when a rat will decides it want to chew on something.

 

[shurmanter]

TSB. 23E07 is software update for oxygen sensor to fix possibility of running with non optimum efficiency. At least that's what my recall notice said

Oooh yes. This is what I was hoping for.

 

[colinl]

my money's on a bad injector. Running lean heats up the cylinders, don't go running it hard.

I agree, especially with the advice to NOT run it hard. If the code is lean, you do not want to drive it hard. There is a limit to what the knock sensor can do and if it's pushed hard when lean, it does not take a lot of detonation to cause significant damage to the piston.

 

[Mike_Sam]

That fact would've been good to put in your original post.

I've had CELs come on after filling up with "suspect" gas. Make sure you fill up with "Top Tier" fuel. And if you have it, try using what we call "real gas" around here. It is ethanol-free and usually pricier. However yesterday, it was down to $2.49 at a station near me. So I'ma switch to it for winter driving. Regular 10% ethanol fuel is down to $2.35

I had this happen on my Transit Connect. The dealership tried to say that since it hadn’t been driven much (i.e., 4000km over 8 months - long story), that it was an accumulation of old/stale or bad gasoline. After a few full fill ups (with “fresh” gas), the problem persisted, so they changed the Mass AirFlow sensor. Since then, I never had the problem again. So I guess it was the MAF sensor.

 

[Silver23]

P0171 System too lean bank 1. Any ideas about this.

look under the hood for any hoses loose. then take it in under warranty.

 

[shurmanter]

look under the hood for any hoses loose. then take it in under warranty.

Yup. Didn’t see anything loose. I’ll be bringing it in for sure.

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