Unsolvable P0171 'System Too Lean' Code

Probably, he stated in the s/c thread that it was TRD. Maybe a typo.

 

To add to this my original spark plug wires were recently replaced couple months ago at around 180k miles. I was driving and it seemed like a "power surge" which freaked me out, took it to the dealer and good as new.

 

This deal does suck! I hate crap like this, drives me nuts sometimes! Especially when it's an ongoing saga, gets real old real fast...

 

Well dang it! Messy detailing job hu? Jeesh...yeah Toyotas finest, ha, what a joke! I agree with hektor, id be over that dealer and be on to the next. Sucks they are so close and convenient though...

 

I just saw this photo on another thread here from a guy selling his 2.7l supercharger. Guy said the s/c was by LC Engineering but there's a TRD decal on the side that you can just see. Wonder if they worked in conjunction with TRD or if the decal was just added for looks?

 

Update on my situation: Dealership is now replacing the o2 sensor (under warranty) to see if that resolves my lean code P0171. As of today I'll have a new MAF sensor, new sparks plugs and wires, and new o2 sensor.

Any other ideas what could cause the truck to throw a lean code if it persists in spite of what's been done? I did read elsewhere that a bad fuel filter could cause it.

At any rate, should have my truck back this afternoon, will keep you guys posted....

 

That's pretty legit, beats me. From the pic it looks like it's etched on there but could be a decal like you said.
On the other hand at least all these new parts on your truck will be preventive maintenance.

 

haha yeah that's what I was thinking, at least my 30,000 miles service pretty soon will be a lot cheaper without having to worry about doing the spark plugs.

 

update: Toyota dealer replaced the o2 sensor to no avail Service advisor called me and said that his techs were "genuinely perplexed, we're going through everything the service manual says to do with this code step by step and nothing is getting it to go away. I have no idea how the San Diego Toyota dealership was able to pass smog with this truck and sell it to you. I recommend you take it back to their service department."

So, I promptly called the San Diego dealership I bought the truck from last month. Told them everything, reminded them I'm still within the 30 day bumper to bumper warranty they offer on all vehicles they sell, and he told me to bring it by and they would do whatever they need to do to make it right. Says he has two techs that specialize in TRD performance parts (superchargers) and wants them to look at it, unfortunately I have to wait 8 days, and it's a 3 hour trip one-way. They only work every other Saturday apparently and I can only get there on a weekend.

I might take it to another Toyota dept this weekend and see if they have any ideas. Starting to wonder if maybe I have a small vacuum leak somewhere.

 

Anyone know of a way to verify or pinpoint a vacuum leak, other than just checking visually? I was revving my engine this morning using the throttle cable and I swear I hear a 'hissing' sound that gets louder with higher RPM's coming from the area by the TPS sensor (in the general area where the air intake meets the upper manifold, I'm still learning so forgive me if I'm off in describing these things).

If I cover the area with my hand it muffles the sound so I think I've narrowed it down to that region. I've checked the lines going to and from that area though and they look good and seem to be firmly attached. Same with the intake hose. But to me that hissing noise doesn't sound normal and might be why I can't shake this lean fuel system code. Worried there may be a crack in one of them that I can't see, maybe underneath one of the lines. Though if it was that simple though you'd think the service techs would've figured it out the three days they had my truck.

 

Fill a spray bottle with soapy water and spray it on your vac lines while the truck is running. if there's a leak, air bubbles should form at that spot

 

That's a good idea, thanks

 

I have a 2005 Corolla that was throwing the same code and it turned out it was a vacuum leak around the intake gasket. I changed it and never looked back (I've got 342,000 miles on that car). Never trust the dealer, the internet and forums are always the way to go. There are way more everyday skilled wrenchers on this site than "certified" Toyota mechanics! Good luck with finding the solution!

 

Thanks man. I'm convinced I'm hearing a leak around the gasket...there's a very audible "hiss" coming from it. Just called the Toyota dealer back that had it this week and they flat out told me they tried everything and basically couldn't help me, useless bunch. Frustrating. So I'm stuck waiting until I can drive it all the way back to the place I bought it from for them to look into it. I'm just worried now that I'm driving around for another 8 days with a code that's putting more fuel into my engine than it needs and it might cause damage because of it. How long did you have the code on your Corolla before you were able to get it figured out?

I guess with the warranty I'm still under, if the engine takes a dump then it's on them to rebuild it...

 

I guess all you can do is let them beat their heads against a wall and maybe that'll knock some sense into 'em and they'll realize they need to go back to school! I would strongly suggest a vacuum leak and see if it gets you somewhere. The code on my Corolla irked me for a few months until I found the answer on a ToyotaNation forum post from believe it or not a former Toyota mechanic!

 

No.

He has a vacuum leak, not a pressure leak. Only thing that will happen is the soapy water will get sucked into the intake.

Better test is to get some starting fluid. Spray it around the suspected leak area. The engine will change tone when the starting fluid is sucked into the intake and burned by the engine.

 

My mileage has started to go down and there's a noticeable power loss, so I'm taking the day off on Monday to drive it down to San Diego and have the original dealership look at it.

I did call Toyota of Pasadena back today (the ones that said they were stumped and couldn't work on it anymore) and asked if I could bring it back and have them check for the vacuum leak I think I'm hearing, he flat out said no...since when does Toyota turn down a job? Honestly a P0171 code shouldn't be this tough to fix.

Anyway come Monday I should hopefully have an answer finally.

 

They turned down because your not paying that's why. Regardless you should call Toyota and report the dealer and the service advisor for turning you down

 

Id also prolly call Toyota and tell them about that stealership not willing to help you, thats a bunch of BS!!! Hardly nothing worse than scandalous mechanics and dealerships. Being a mechanic is not an easy gig especially if you're a business owner. But dang it just sucks when you get caught up with a bad one and have real issues with your rig. Seems more and more common these days to get taken advantage of. I apologize to the great and honest mechanics out there, im not putting you in that group of peckerheads out there!! They really give you honest guys sorta a bad name if someone has had a bad experience. Makes it hard for people to fully trust you.

Also ole koditten is right! Im suprised jt took that long for someone to catch that error. The soapy water definitely wont help find a vac leak, lol. But yeah, use starting fluid. If its a big enough leak to throw the code then it should be big enough you will notice the motor jump a few rpm's when the ether hits the combustion chamber! That'll tell ya right there if its the problem or not!!

 

What's this "ole" shit, Bry? I'm 45 years old.