"Too lean" means that the engine is not receiving enough fuel for the amount of air coming into the engine. In other words, the engine is receiving more than 14 parts of air for 1 part of fuel. (Internal combustion engines run best at this air/fuel ratio.) While there can be numerous causes for this code to be set, on 2005 - 2008 Toyota Corollas, the repair is usually quite simple. 99% of the time, I have found the cause of a P0171 for 2005-2008 Toyota Corollas with 1ZZ-FE engines to be the intake gaskets. The problem is so common, Toyota even put out a technical service bulletin for it. For a mechanically inclined person, doing this repair can save a couple hundred dollars because the cost of the part to fix this issue is usually not more than $10.
The problem with the Corollas is that the old intake gaskets on the Corollas with the 1ZZ-FE engines is that over time, they harden and lose their elasticity. This allows unmetered air to sneak past the gasket and into the intake manifold, thereby causing a lean condition. Here's how to fix the problem.
First let's take a look at what you seen when you first open the hood.
Remove the plastic engine cover, and remove the intake tube from the air cleaner housing to the throttle body, and you've got this:
Next, remove the two 10mm bolts and two 10mm nuts holding the throttle body onto the intake manifold. Seperate the throttle body from the intake manifold, but you do not need to take the throttle body completely off the car. Just set it to the side with the coolant hoses still attached to it.
Now remove all the bolts holding the manifold to the engine cylinder head. Once you have all the bolts removed, you shouldn't have to fight it out, the manifold should easily pull right out. If it doesn't pull up off the engine easily, you probably haven't removed all the bolts. Here's how the engine bay looks with the manifold removed.
The intake manifold gasket is a one piece rubber gasket. If it is still a factory installed gasket, the gasket will be black. Go ahead and pull the old gasket off.
The new & improved intake manifold replacement gasket is orange. Install it onto the intake.
Once you have installed the new intake manifold gasket, you are ready to install the intake back onto the car. Once you have installed the intake back onto the car, start the engine and spray some carbueretor cleaner around where the intake manifold is. If there is still a vacuum leak present, the engine will idle down. If there is no vacuum leak, the engine rpm will not change as you spray carb cleaner around the intake. Of all the Corollas I have put intake gaskets on, only one required further attention after replacing the gasket. Oh, and don't forget to clear the DTC with your scan tool so the check engine light will turn off.
Most customers at our shop pay $170 - $200 (primarily for diagnosis and labor) for this easy repair on Corollas. If you're mechanically inclined, try to replace the intake gasket yourself, and you just may save a couple hundred Dollars.
This just happened to my 2005 Toyota Corolla S. I have also been experiencing horrible gas mileage lately. Is that consistent with this problem? Everyone else told me it was probably the Oxygen Sensor that had to be replaced.
ReplyDeleteIt's really hard to say without looking at the vehicle Joe. The best thing to do would be to get your ECU scanned so that you check if there are any trouble codes present and then proceed accordingly. There are a couple things you can do without scanning the ECU just to eliminate the obvious: check to make sure your air filter isn't clogged with dirt, make sure your tires are inflated properly (underinflated tires have higher rolling resistance which causes higher fuel consumption).
DeleteThe gasket fix will def solve horrible gas mileage issues, and the check engine light. My car ran great before I changed it, even with the light on. I noticed the gas mileage was getting worse, but just figured i was running it too hard. Once the light came on and started reading up on it, it all made sense. i did try to clean the MAF first, but unless your car is bucking, hesitating, and popping I doubt that is the problem.
DeleteI'm getting my intake gasket replaced at 70,000 miles on my 2008 corolla. If this is such a common problem, why didn't Toyota change after 2005? It's a bad call by Toyota to keep a cheap poor quality part in their cars. So much for quality.
ReplyDeleteHonestly, if I had to make an educated guess, the replacement gaskets that we are putting on the cars will have the same problem in 5-7 years. Any flexible rubber part or gasket which is subjected to high heat (like that of an engine bay) will probably harden and lose elasticity over time. Plastic intakes and small rubber gaskets are lightweight, which help contribute to an overall light weight of the vehicle, which in turn contributes to higher miles per gallon. Unfortunately, this design is also prone to the occasional P0171 problem. In the automotive engineering world, its difficult to let us consumers have our cake and eat it too.
DeleteWe bought a 2006 Toyota and the TCB (technical service bulletin) was already out in 2004 according to Toyota.
DeleteI get so sick of engineers using plastic parts!!!
Kawasaki put in plastic oil pump gears on some v twin engines.
Guess what... the plastic gear swelled up in the hot oil and broke off. Many engines were lost. I sure would like to see one of those engineers's faces.
This just happened to my 2007 Corolla with 66,900 miles. Check engine light was on. Vehicle had code in system of po171 ... to much air was getting through the intake manifold so replaced intake gasket. Too bad I did not catch your post. Gasket was $10.55. Computer/scan was $66.80 Labor was $177.55. Ouch.
ReplyDeleteMy wife has an 08 Corolla with the same problem. Toyota wanted over $400 to do the repair. I just bought the Felpro intake gasket for $4.99 + tax. My labor cost $0. Wife's happiness, Priceless!!!!!!!!!
ReplyDeleteThanks
I'm happy it helped you!
DeleteI am going to attempt this. I saw that in the original instructions that you said to make sure you clear the DTC with the scan tool. if I do this at home, will I have to take this in to get it cleared?
DeleteYou can just go to one of the auto parts places like Autozone or Advanced Autoparts or O'Reilly's or what ever and they should clear it for free!
DeleteThanks for posting this! I replaced my gasket today and this was super helpful!
ReplyDeleteA word of caution, that should go without saying... make sure you plug all the hoses back into their correct spots. I made a wrong connection and the car did some strange things, lucky nothing broke!
You're absolutely right Aldo, vacuum hoses in the wrong spot will cause strange driveability problems and possibly check engine lights as well. One great way to prevent this problem in the age of smart phones is to take a picture of what you are working on prior to disassembly. That way, you will have a picture so you will know exactly how to go back together with it! (I sure wish smart phones existed when I first started in this business, they have made my life so much easier!)
Deleteone bit of advice on replacing the gasket - it's easier to get the throttle body off if you disconnect the air intake duct first. You will be able get to the 2 nuts and 2 bolts easier. And yes, be sure the hoses all go back correctly. BTW, good write-up Mech254...very helpful
DeleteI think I am having this problem as well. I ordered the part from Auto Zone, but the gasket they gave me is not rubber; it is a light metal material. It is Felpro Part number 93867 (http://shopping.yahoo.com/886817127-felpro-intake-manifold-gasket-set-ms-93867-1/). Is this the wrong part? Should I have a rubber gasket like in the tutorial above?
ReplyDeleteSounds like you were given either an exhaust manifold gasket. I would have them double check the part. The intake gasket should be rubber material.
DeleteCould someone give me the correct part#'s to order these gaskets from auto Zone.
DeleteThanks
MD
First of all, thank you so much for sharing your solution.
ReplyDeleteAs a newbee to the DIY maintenance, it was quite easy to follow the directions.
I had the same code read by Autozone person. Took my 07 corolla to the dealer and the receptionist said it may be the intake gasket though Autozone clerk was very skeptical on that.
Cancelled my reservation to the dealer shop, bought MAF cleaning spray but it didn't work, so bought the gasket($4.99)
1. Took the plastic engine cover out by unscrewing 2 metal bolts and 2 black plastic ones with flat head driver. Lost one of the plastic bolt, so newbees be careful. But fortunately could find it on the ground when I started the engine after installation.
The rattling made it to drop down on the ground.
2. detached big rubber hose between the filter box and throttle(?). Electric wires holder and about 1" hose are connected to this big air hose. didn't detach any of them.
On the picture above, the 1" hose on the engine side is detached. Mine was a bit hard to pull it out and was afraid of damaging the hose.
3. Took the throttle out. 2 nuts are on the front, 2 bolts on the back. put the throttle aside.
4. Started unscrewing bolts by the throttle. There were 3 rubber hoses. 2 by the 2 bolts, 1 in the backward side. At first, started unscrewing leaving hoses still attatched and found one of them damaged slightly, so stopped and detached 2 hoses. Still no fluid came out. ;)
There were 6 bolt and nuts on the top and side and one more on the right bottom.
5. Slightly took the manifold out and pulled out the 1 rubber hose connected on the backward side around the throttle part by using plyer. Couldn't unlock the hose clamp so just pushed it back. It seemed all hose clamps were not holding the hoses that strong.
6. Top of the manifold was stuck with the wires on the top side. So took the wire supporter out on the very top left side. Could see those cute little pistons(?).
7. Was easy to replace the gasket. Reassembled and it worked. ;)
!!!!!!!!!!! Thank you so much again !!!!!!!!!!!!!!
My own labor gave me happiness in addition to saving the money. I'd like to change brake pads on my forester next time before it gets too cold.
Glad it helped newbee!
DeleteIt seems that Toyota is focusing in building the new concept for Toyota Corolla. And I think there are a lot that is complaining about the unreliable parts of this car.
ReplyDeleteYes, there have been some problems with the newer Corollas (2011-2012 year models). Mostly what I have seen have been faulty alternators and faulty water pumps. They're easy fixes if they are caught in time.
DeleteHave this same code on a 2005 Corolla CE at 83,000 miles. Will be changing out the gasket myself. Thanks for the awesome write up!
ReplyDeleteYou're most welcome Brad
DeleteI got the P0171 code but not sure if its the intake gasket or o2 sensor ( or something entirely different). How do I know what is causing the code?
ReplyDeleteYou don't know unless you take it a shop and they can use a better scan tool which can eliminate a few possibilities. But most will just base their diagnosis on experience and your symptoms. How is your car running?
DeleteI'm not sure how to describe it. I gave it a tune-up thinking it would fix the problem but it's still having this weird feeling when it drives. Sometimes the car feels like it needs gas and has a weird start/stop feeling. It kind of shakes a bit then it's fine again.
DeleteI've had this issue over the last 6 weeks and my mechanic says he can't figure out what it is because he can't detect any leaks around the intake manifold gasket - we've been through everything from changing out sensors to cleaning the air mass sensor to tightening the loose air inlet pipe - is it hard to detect a leak at the intake gasket site? otherwise the car runs pretty well, except for a few shudders when we're stopped at a red light. Should we just replace it anyways and see?
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteIs the chk eng light on? It may not appear to be leaking when searching for it at idle. It may appear more at higher speeds when there is more air needed. I would replace it even if he can not tell if it's bad. It's an hour job, and a $5.00 part - totally worth it even if it doesn't cure it. At least that would be one more thing that's eliminated
DeleteI have the same code on my 2006 Corolla. A friend of mine replaced the intake manifold gasket but a few days later the light came back on. Do you have any other suggestions on what it could be? The mechanics want to charge me $50-$90 just to do the diagnostic test on it. That seems like a lot of money to spend for my car to still be broken. It's been a little slow to start and it's idling a little rough. Other than that it really seems fine.
ReplyDeleteThank you so much mechanic254. I lucked out. Went to replace intake gasket on 2005 corolla Le because engine light came on and engine was rough at idle. Decided to replace air filter first because advanced auto had to order the gasket. Popped hood, immediately noticed one of the clamps on the housing was not secured properly. Replaced air filter closed lid on housing, secured the clamps and voila'. Problem solved. Engine light went off on its own and engine idle returned to normal. Just wondering if i should replace the gasket anyway or wait till there's a problem. Thanks Again.
ReplyDeleteFirst of all, thank you so much, mechanic254. I've got the same code and just replaced the intake manifold gasket today.
ReplyDeleteHere I have one question now. I've just realized the revised original toyota gasket part number is 17171–22060 and its color is orange as your photo. What I've installed is Fel-Pro part #MS93942 from Autozone and its black. Should I replace it again to the orange one? Thanks again and happy new year!
One auto parts place also offered to sell me the old black O rings. I declined and ordered the new improved gasket from the Toyota dealer.
DeleteGreat instructions. Swapped mine out in about an hour. $5 in parts sure beats $300 at the dealer! The intake manifold is held on with 2 nuts on locating studs and 4 bolts - all 12mm (2006 Corolla). Do yourself a favor and disconnect the electrical connector from the throttle body and a few of the vacuum hoses. This will allow you to get things out of the way a little easier.
ReplyDeleteOur Toyota had the check engine light come on after several days of below freezing weather. Mileage was 72,000 2006 Corolla LE.
ReplyDeleteI have an OBDII and THe code was PO171 Lean condition.
I called Two of the largest Toyota dealers in my area . They did not have the part!
Napa and O'Riely's auto parts did not have the part either.
I wondered why none of them did not have the part if it was a common problem and there was a TSB (technical service bulletin) .
I sprayed carb cleaner around the intake manifold when it was warmed up and running. No change in the rpm at all.
Then I cleaned the MAF sensor with special MAF cleaner although it looked clean.
Put it all back together. Erased the code.
The check engine light has not come on.
The service manager at one of the dealerships told me they had never replaced that intake manifold gasket in question. He tried to get me to bring my car in and pay him $135 to scan the codes.
The instruction sheet that I got with the new orange gasket I ordered from Toyota
had a step by step instruction, It said to drain the cooling system etc.,.
The last step said to remove the battery cable for 90 seconds to build a new profile.
So now I am wondering what is the difference from cleaning the code with the OBDII button or disconnecting the battery for 90 seconds?
So the dealers are getting $135 from who knows how many people for just clearing codes? I get so sick of dealers and they would not let me talk to a mechanic. Said they were at lunch etc.,. I drove by the garage area and the garage was bustling with cars and mechanics.
I have been getting a P0133 Bank 1 Sensor 1 code on my 2004 corolla every winter. It disappears when winter's over. The Toyota service bulletin says (like P0171) this could also be due to the intake manifold gasket. My mechanic had suggested o2 sensor replacement. How can I be sure if it not a leaky gasket? Thanks.
ReplyDeleteI have a 2005 Corolla CE with 112000 miles. I had my check engine light come on and took it to AutoZone. I got P0171 Bank 1 System too lean code. The guy said I needed to replace a sensor. I went by PepBoys and the guy said I needed to replace both sensors. Since my Corolla is older and has higher milage they are probably both going. I then went to a new AutoZone and he said the same thing, replace both sensors. This will run about $230.
ReplyDeleteI like the idea of having a $5 fix, if that will fix the issue. No one I talked to at the 3 places mentioned the intake manifold gasket. Since I am over 100000, should I replace the sensors or start with the gasket?
Hi all, let me add my own thank you to the original poster and to all the people who have replied.
ReplyDeleteI have a 2006 Corolla with 65k miles and I got the code. Well my experience did not go beyond engine/trans changes and brake jobs. This gasket change was easy enough for me to do. In fact I took my time and cleaned out the throttle body and the intake manifold while it was apart. Was really oily and gassy smelly. I had a bit of trouble getting the manifold in and out because it was bumping against the coolant overflow tank. But anyway a little patience and jiggering and it was easy enough.
This was a very cathartic experience and I knew that if it did not work i could always spend way more bucks and start on replacing one by one the O2 and MAF sensors.... There is nothing more satisfying than seeing that check engine light go away with such an easy and cheap fix!
Oh by the way, replacing the gasket has made idling a little smoother too.
Just over 100k miles on my Corolla and this is the first fault. Thanks for the tips on this page. Took less than an hour to repair and a part that cost less than $6!! Can't believe I would've paid as much as $400 for this! Test drive went well and it idles much smoother now. Just hope I got the problem solved.
ReplyDeleteI did this repair yesterday but for some reason the brakes have locked up. I can barely push them down hard enough to get it to brake even slightly. How is this related and what did I do wrong?
ReplyDeleteAlso, I must have done the repair wrong anyway because the rough idling is worse than before. I need more mechanic friends.
LOL!!!! Dude, you swapped vacuume lines.
DeleteThank you very much for this guide. My 2005 corolla s has 150,000 miles and had been running very poorly. It was also getting terrible gas mileage. I checked my engine codes and sure enough it was showing P0171. I did a quick internet search, found your guide and had the new gasket in within an hour. My car is running much better now. Thanks again!
ReplyDeleteI got the same code in my corolla 2006 34k miles. Just installed new manifold intake gasket the instructions are really good.if you are not too mechanical inclide but want to give it a try go to youtube and search for " corolla intakr manifold" there is a good video that shows step by step the process to change it. It is for a corolla matrix but engine and components are exactly the same as in the corolla. I'm going to borrow the scanner tomorrow fro autozone to clean up the code and turn the engine light off. Everything seems to be all right now. It just cost me $6 the original toyota part at the dealer and a couple of hours of my time well spent
ReplyDeleteBrilliant!
ReplyDelete2005 Corolla CE P0170 code 40K miles. Replaced the intake manifold gasket (p/n 17171-22060 $9.10) and throttle body gasket (p/n 22271-0D051 $6.84). The mass air flow rate at idle went from 0.33 g/s to 2.12 g/s. Problem solved!
The throttle body gasket was compressed but could probably have been reused; however, for just a few bucks, I don't have to worry about it in the future.
I also cleaned the MAF sensor for good luck. It took 5 minutes and I recommend cleaning it whenever replacing the air filter.
Thanks!
Thank you so much for posting this; mechanical things can be so daunting and being able to do some of it myself has been a financial life saver. I have been very fortunate with my 2002 corolla, it has 104K miles. I have just replaced an ignition coil and have really had no other problems in the 9 years I have owned it. Thanks again!
ReplyDeleteCan someone post a video of the entire Gasket replacement?
ReplyDeleteI am a newbie and I would like to save $200 if i can help it.
I am mechanically inclined and can follow steps, but it would be nice to see it done on Youtube
Thanks in advance
Rahil
I posted my video on youtube: http://www.youtube.com/watch?v=C57HESFxQfc
ReplyDeleteBTW, this problem effects 2003-2008 corolla/matrix and not just 2005-2008. Mine is 2003.
There is TSB available on the net to download with all details: EG045-07.
This is such a great resource that you are providing and you give it away free. I love
ReplyDeleteseeing website that understands the value of providing a quality resource for free.
Regards
Fuel hose
Great post, a very informative post along with pictures makes things much more clear and easier to understand...Diesel nozzle
ReplyDeletegreat article. i just did the gasket for my mothers car. 1 thing that worried me tho is that there was no mention of torque for the manifold bolts. i tightened them in the cross pattern for both the manifold and the throttle body. i assume the TB gasket doesnt have to be replaced.
ReplyDeletebut my main concern/question is. What torque should they be tightened to?
i tightened them pretty tight, hopefully this does not cause future problems.
thanks.
Comparing this older version of Toyota Corolla to the newer one I would say that this model have grown. Though the old car is kind of edgy I’m sure that its engine performs great!
ReplyDeleteHi, I tried changing the gasket on my own, but was not able to remove the bolts on the intake manifold as they were too tight using a 6 inch load arm from my home tool kit. Do I need a power drill to open it? Or do you recommend any particular tool for this? Thanks
ReplyDeleteDude, you need more tools. Go to Harbor Freight Tool or Sears and get a set with 1/2" drive deep and regular sockets, breaker bar, as well as some long handle ratchets. Or, you could just use a cheater bar. Go to the hardware store and get a 12" to 18" length of PVC pipe that will fit over the handle of your ratchet. But be careful, if the bolt is too tight, you could break your ratchet. Using 1/2" drive tools is better if you can fit them into the space.
DeleteI am a "girl" and was able to follow these instructions and fix my car and save a couple hundred dollars. The gasket cost me $4.99 plus tax. Thanks for the help. Also the guy at O'Reilly refused to clear my code so I just unhooked the negative battery terminal for 60 seconds and put it back on...code cleared...check engine light off...car running light a dream again.
ReplyDeleteThanks for this walkthrough. My wife's Corolla has been plagued by this P0171 code for 2 years and it only comes back in the winter.
ReplyDeleteFor anyone else reading this, you dont actually have to reset the Check Engine Light, once the car adjusts that the car is no longer running lean, it will go away on its own. It might take a couple days and 50-100 miles worth of driving, but the OBDII system will clear codes on its own once the problem is resolved.
Also, to add additional clarity to the original instructions, there are 4 bolts and 2 nuts that hold the intake on all of which are 12mm. 5 of them are near the top, and there is a 6th one down below.
@Anand, there shouldnt be any special tool neeeded to remove the bolts/nuts. Just a simple set of sockets should work. I used a 12mm crescent wrench to get the lower bolt because it gave me additional leverage.
Yeah, the codes will eventually clear on their own, but what if the gasket wasn't the only problem? You need to clear the codes so you can drive it and see if the MIL (Malfunction Indicator Light) comes back and another code gets stored because you swapped vaccuumme(@#*$!!! How the hell do you spell vaccuume, vacuume,?)lines or something. You can clear the codes by disconnecting the negative battery terminal for 90 seconds or longer.
DeleteI replace the gasket and MAF sensor and still get the same code. I even clear it twice and it comes back. Don't know what to do.
ReplyDeleteNeed help! I tried this repair and I was not able to get the manifold to move enough for me to get the gasket out. So, I put everything back and now my car starts but it shuts off after it starts. My car is a 2002 Chevy Prizm, which is pretty much the same as the Corolla. Any ideas?
ReplyDeleteYou have created a much bigger vaccuume leak. You need to start over and REMOVE the intake manifold, not just move it. You need to take it out completely and put the new gasket on the manifold in the groove. You can't do it competently, leaving the intake manifold on the car. Get a helper.
Deleteyou know I've seen my fair share of "advice web sites" but in my book you score the top gun of 'em all. simple , direct to the point & in layman terms. Thanks, next round of beers on me, M8.
ReplyDeleteWell, with the huge market of used cars for sure it will help increase the said percent of income from Japanese cars. When it comes to reliability and speed performance of Toyota, you’ll never get wrong with it.
ReplyDeleteI have 2008 Matrix Base with 1ZZFE, had the same code showing engine lean.
ReplyDeleteI got mechanic replaced manifold gasket, MAF, O2 sensor before cat.
After all this the engine light still showing the code engine lean.
Please help