P0171 Explained - System TOO LEAN (Bank 1)

The FIXD wireless OBD2 scanner and free app for iPhone and Android translates your check engine light into plain English so you can rest easy. In this video, we explain what OBD2 code P0171 means and possible causes.
P0171 means your engine is running too lean (too much air or not enough fuel) in bank 1 of your engine. Combustion engines run most efficiently when they maintain an air-fuel mixture ratio of 14.7 parts air to 1 part fuel. When there are more than 14.7 parts air to 1 part fuel in the air-fuel mixture, a lean condition exists and code P0171 is triggered.
The lean condition can be caused by a vacuum leak, which introduces more air into the air-fuel mixture, or by a weak fuel system, which does not input enough fuel into the air-fuel mixture. To keep the engine running properly, the powertrain control module (PCM) tries to compensate for the lean condition by injecting more fuel to the mixture in an effort to maintain the proper 14.7:1 ratio. When these adjustments become too large, code P0171 is triggered.
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0:00 P0171 - System Too Lean in Bank 1
0:09 P0171 is caused when the ratio of fuel to oxygen is off in Bank 1
0:29 Lean relates to ratio of fuel to oxygen
0:40 Power Train Control Module (PCM)
1:10 Possible Causes of P0171
1:51 Visit our blog to learn more about P0171
2:06 Happy Driving!
#FIXD #P0171 #checkenginelight

[@BobSnyderAuto]

Love the straightforward explanation! The best part of this video is that it explains WHY this is happening. Too many times there is no diagnosis, simply just throw this O2 sensor on and it is fixed...It is so important to know HOW the symptoms are related to the solution.

[@Cayoroots]

This channel needs more followers

[@fixdapp]

We appreciate that, and sometimes think the same thing. :D

[@guesswhomartin9249]

Wow... You explained it the best so far. I just joined you, and I hit the like button.

[@humbertocastillo6043]

Fixd is very good , i can find right way the problem when i have the engine light on...i love it. thank you.

[@timpace9216]

Great information and explanation

[@anthonyibarra7512]

Very informative....Thank You

[@BORICUACHANNEL]

Love Your Video

[@fixdapp]

Thank you, Boricua, for the kind words! We appreciate you taking the time to watch. 😊

[@oddsins4350]

I pulled the fuel pump unit from the gas tank and changed the filter it fix my rough idle and long and no crank problems. I had this dam code for 2 years I did everything it’s still there I give up screw this dam car

[@sramBC]

Change gas cap. Maybe it’s the ecm

[@tonylopez6585]

Maybe it’s faulty header gaskets?

[@anthonybrowning6833]

Vacuum leak try a smoke machine 2:00

[@Richard-vl2vz]

Just found my type,, thank you P 0717. Let's get rich!!!

[@fatdudeswag404]

Great to know

[@fixdapp]

Glad to have helped! Let us know if you need anything else.

[@brandon9161]

How do I know which nine it is, p0171 could be either one too much 02 or 2 little fuel?

[@imatter4619]

Great video. My 97 Oldsmobile 88 has this code and on Top of that the car doesn't start half the time. As I turn the key it makes it's usual noise but doesn't start, and eventually it starts and runs fine. PLEASE HELP

[@user-zc1rb6lu4c]

The problem was a vacuum leak I had disconnected the tubing running from the exhaust manifold to the EGR valve because of a low EGR flow code. The reason for that was because I couldn't get the bolts out of the EGR valve without them snapping so I was using this method to spray through the EGR valve 2 possibly unstick it if it was stuck and maybe possibly the cleaner would go through the EGR completely and possibly break the carbon up in the EGR channels. The cleaner was a seafoam product used to inject through air ducts while engine was running. It seemed to have fixed the problem but not entirely I may have to do it again and see where that lands me since I can't get the EGR valve off without snapping the bolts.

[@jaemajor]

Ended up being my exhaust manifold.. 1k job

[@shadzuchiha6691]

Can also be caused by Dirty intake filters

[@RussellBooth1977]

I keep on getting a P0171 code in a Chevrolet LS1 V8 powered car,the fuel pressure seems to be low at 50 PSI & there seems to be air in the fuel when checked the fuel volume,the fuel pressure should be 55-62 PSI. So,the first thing I'll change will be the fuel filter before anything else,I've already changed the fuel filler cap which was leaking air into the fuel tank,note no P0442 is listed for my car as the engine is in a Holden who didn't fit a fuel tank pressure sensor !

[@ogredz3361]

I have this same code but it shows bank 1 and bank 2 too lean. Would this be the same for O2 sensors

[@fordaman2360]

total babe and awesome presentation

[@godfredfosu1828]

Good

[@virusboy07]

@TheJudge01 indeed.

[@66coltrane]

You call that a babe ! She’s cute but a babe is tooooo far.

[@jawharris]

@@66coltrane If she were in a bikini in the video, would you believe she was a babe? If she were in that bikini, I suspect you would give her no credibility. She is a good balance.

[@adrianhayden7036]

She don't need no bikini to be a babe.. I'll give credit, where credit is due! She's welcome in my shop anyday..!

[@jagr06]

Sadly for me i've invested tons of money fixing the MAFS and other shit and it still is on. When I had them check in the morning before I left for work they literally said nothing is wrong inside and maybe I should change gas stations or fuel types. And unfortunately that too did nothing the past 6 months BUT when I needed to have a oil change the light decided to turn off when they decided to do my inspection Early July and It popped back up the following day. At this point i feel like the light and the code is all bullshit, as it's trolling me.

[@Abdulaziz-lo6nx]

I am today check mazda6 2016 show dashboard engine check light.. After i am connect the diagnostic cable show me P0171 Lenk bank 2

[@vihumajimartz6881]

How to fix that because I have a Mazda 6 2014 y the same code P0171 and I don’t know what to do

[@RitchardWithaT]

Wouldn’t bank 2 be lean if it was a bad fuel pump tho?

[@heathcalvert1319]

1999 5.9 Durango help got a p0171 code how do i get rid of it

[@stacyg3425]

Can this have anything to do with the muffler or muffler valve. I just bought a used car and 3 days later the engine oil turned on with codes P0171 and P0174 . I contacted the dealer and they said they’d check it but it was most likely a valve in the muffler? I don’t know much about cars. Help would be great.

[@Lafortune100]

how did u fix it , i got p0171 and been trynna fix it for 2 days

[@NEKROBAT666]

Damn, soo many things can be wrong 😩

[@stevemendess2683]

but all very very minor

[@stevemendess2683]

@@reignman0311 but it's not urgent,,of course is a major difference after a spark plug change oil change etc,,but if the basics are done..then that check engine light shouldn't b on

[@mrlambo2972]

@@reignman0311 on my friends bmw it was a dirty injector and what I did was add Fuel system All in one cleaner and it took 2 of them and it did the job. I told him drive it for a while and yes the issue fixed while he was driving 💯💯 I checked everything else and no other issue was found

[@SchrodingersBox]

Not too bad. 98% of people would just change an O2 only because the code mentions the words O2 sensor. Actually, O2 sensor is not the most common culprit. In fact, if the LTFT is able to set a functional baseline with a zero’d STFT, it is mathematically impossible the O2 can be faulty. But no, no- people just rev up their parts cannon anyway.

[@mharradine57]

Ha, hilarious. I just mentioned your video as a reply to one of the comments on here after someone complained about other videos going on and on...This tool just pisses me off, making people think it is going to tell them what part to change. People were doing this with Actron code readers in 1996. The video even helped direct them to replace the o2 sensor! I noticed that there were no videos telling what part to change with a U1000 code..."Just tell me what to start swapping!"

[@LonelyBrownEyes1977]

Code readers are just that, they are code readers and not a problem solver. They give a code, its thru PROPER DIAGNOSTICS that you find the real problem and can fix the issue. Codes merely just point you in a direction to get started. Many other issues can set a MIL indicator or check engine light. Problem with todays economy is vehicle owners DO NOT want to pay the labor price to have their stuff diagnosed and fixed, although they'll stupidly spend money just throwing parts at it and eventually getting lucky only afyer replacing everything that wasnt even the problem.

[@reignman0311]

lol, exactly,when I saw the ad for it, I laughed coz it does not tell you exactly what it is and how much it's gonna cost, like you said, it gives you a place to start looking at just as this vid is saying,was like 6 different parts that could be bad or not working correctly,

[@bowendevin2070]

i guess I am kinda randomly asking but do anyone know a good website to stream newly released movies online ?

[@bodenthatcher6738]

@Bowen Devin Flixportal :P

[@3dentertainment301]

Good lord she is VERY ATTRACTIVE. Now that's someone I'd like to see every day ;)

[@stevemendess2683]

Not a serious problem,change the spark plugs yesterday when off..n light came back on..after 24 hrs

[@adrianperez1550]

Does this make the car shut down ?

[@ceasarslimer68]

Could it make a car not go over 15 mph

[@chrisalarcon7013]

nice vid and the gorgeous girl was a nice touch as well

[@fixdapp]

Glad you enjoyed it!

[@JeffTheHokie]

Mine's throwing that code, but running so rich it's painting the driveway under the exhaust pipe black. It's not a vacuum leak or a fuel shortage. Something is giving the computer an incorrect reading

[@DrummerDanVa]

I got this code on a Mazda 5 less than two weeks after it had been serviced. I found something online and sure enough the tech must have opened the air filter housing to check it and didn't get the entire housing back in its proper place. After making sure everything was secure and clearing the code it has been fine. I check gas mileage every fillup and as long as the car is running fine these codes can be bullsh*t. Another money grab to get you to come in to pay $150 for the dealer to read the codes.

[@johnnydoggs]

Yo honey good video

[@Brunotravelchannel]

Could a bad rear main seal cause it also?

[@fixdapp]

That is a good question. The answer is YES it can. A leaking or failing rear main seal can cause the fuel trims to run lean by allowing excess air into the system. Many modern engines in cars of today will run poorly and throw a fault code and or a check engine light for a lean condition simply by pulling out the oil dipstick on the engine and having it not seat properly. This again allows excess air into the system.

[@williamplatt6859]

The sensors can be cleaned but, if that doesn’t do the trick, a new sensor or sensors will fix.

[@IYBN8623]

ok so what are the dangers of continuing to drive it for a day or two till you can get it into the shop??

[@lankmasterplaysminecraft2858]

Nick M I’ve been driving with mine on for like 6 months. A day or 2 is fine

[@darthtrader1027]

I'm gonna start by cleaning my mass airflow sensor and putting in a clean air filter... If that doesn't do it, I'm gonna get some fuel injector cleaner and spray around the intake manifold to see if it has any effect on the engine idle sound... If it does then I need to replace the intake gasket... If that doesn't fix it I'm gonna have to throw a new air flow sensor in. Hoping I guessed right with the MAF sensor.

[@elizabethlamboy-wilson7335]

I''ve been driving my Toyota 2003 Camry with this check engine light on for 2 months with this code. It's not that big a deal but in order to make sure you have no engine issues in the future, try to get it fixed as soon as you can.

[@Richard-vl2vz]

For myself, I needed to tighten my exhaust flanges right out of the header on the passenger side..car runs brand new....

[@stevemendess2683]

@@elizabethlamboy-wilson7335 mine was the spark plugs...then the light return this morningsmh,,I too own a 02 camry with nearly 300kmile

[@CatMan81]

Or a bad purge valve.

[@PinkysHouse]

What if it's both P0174 and P0171

[@JasonSpitzMI50]

OMG 😍 Where have you been all my life. I love a woman that knows something about a car 😍

[@plainoldme7322]

I am willing to bet my code happens when I use at least a half tank of E85 gas and my truck is not designed to use it

[@teeti9401]

It looks nice to see a girl in the field of Mechanics. Nice presentation.

[@edaguirre6723]

Hi my name is edy babe