P0171 - "System Too Lean Bank 1"

[Joe 5.0]

My car is throwing a P0171 code and I'm not sure why. A few Google searches have informed me that it could be a number of things causing this code, such as a vacuum leak, dirty MAF sensor, bad O2 sensor, etc. The code popped up after a hard pull.

I checked my JLT intake tube, and the clamp by the TB was pretty loose. I tightened that up, took the car for a spin, but the CEL is still glaring. I plan on buying some MAF sensor cleaner and spraying it down this weekend.

I'm reluctant to clear the code, because I want to make sure the problem is fixed so I can continue to enjoy the car.

Someone mentioned that it could be my Lund tune? I've been running the same tune for months, and have had no issues, so I doubt that is the problem.


Any thoughts and input would be greatly appreciated! Thank you all in advance.


Performance Mods:
JLT Intake
SW Catted Headers
Borla Sport Catback
Lund Tune

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[GuardGT]

mine did this when i *thought* i installed my flex fuel tune, but it was the 93 gas tune, then filled the tank with e85. lol oops

 

[dubster99]

I'd be willing to bet it was that loose clamp letting in too much unmetered air. Clear it and see if it comes back.

 

[MyFirst5.0]

^^^what he said, you prob fixed the problem so clear the code and see what happens. it may go away after a while, but you will know a lot faster if you just clear it and see if it comes back

 

[Jn2]

P0171 is triggered at 1.29 Lambda, so you should log your LTFT+STFT and make sure they are as close to zero as possible, ideally you want to be +/-2% at all times. Some fluctuation during decel is normal, but while driving you should be pretty close to zero.

If you threw a P0171 then you most likely hit a +30 at one point or another a few times in order to trip the code.

 

[Joe 5.0]

Thank you all!

So it seems like it was the loose clamp on my JLT intake. I tightened up the clamp and took the car for a spin for 20 minutes on the highway. The next day I started the car, the code was gone on its own.

For anyone that throws this code in the future:

1. Check your air intake for loose clamps/components
2. Clean your MAF sensor if step one doesn't work
3. Check for a vacuum leak (very simple to do, just check Youtube)

 

[2morrow]

Thank you all!

So it seems like it was the loose clamp on my JLT intake. I tightened up the clamp and took the car for a spin for 20 minutes on the highway. The next day I started the car, the code was gone on its own.

For anyone that throws this code in the future:

1. Check your air intake for loose clamps/components
2. Clean your MAF sensor if step one doesn't work
3. Check for a vacuum leak (very simple to do, just check Youtube)

Thanks for this

 

[Joe 5.0]

Thanks for this

Glad my post helped! I try my best to post solutions to my issues so it takes the leg work out of the equation for other members.

 

[Chavez38]

P0171 is triggered at 1.29 Lambda, so you should log your LTFT+STFT and make sure they are as close to zero as possible, ideally you want to be +/-2% at all times. Some fluctuation during decel is normal, but while driving you should be pretty close to zero.

If you threw a P0171 then you most likely hit a +30 at one point or another a few times in order to trip the code.

 

[Chavez38]

I'm getting these codes with my cai jlt and lund tune also can't figure it out...with my stock intake codes go away runs fine any idea what this could be

 

[SheepDog]

I'm getting these codes with my cai jlt and lund tune also can't figure it out...with my stock intake codes go away runs fine any idea what this could be

Did you purchase the "tune required" intake, or "no tune required" intake?

 

[Chavez38]

Tune required

 

[ice445]

I'm getting these codes with my cai jlt and lund tune also can't figure it out...with my stock intake codes go away runs fine any idea what this could be

The tune isn't correct for the new intake tube is my guess

 

[SheepDog]

Tune required

Are you flashing back to the stock file when re-installing the OEM intake?

If not, and you are using the Lund tune when switching back to the OEM intake, the tune is the problem.

Make sure you tell Lund that you have the "tune required" intake, and make sure that the part you received from JLT is actually the tune required version (CAI-FMG-18)

 

[Chavez38]

They sent me 2 files 1 for the jlt intake and 1 for stock intake so yes i do swictch tune back to stock intake...I told them I thought the tune was wrong but they say it's mechanical but if it was mechanical i would get codes with stock intake 2 right

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