DTC P0174 Lean Condition: The Fix

[spitin venom]

I was driving home from work and my SES light came on. I instantly checked my interceptor gauges and it gave me a P0174 (similar to P0171 code) lean condition bank 2. P0174 is a pretty generic DTC that can have MANY causes. Most of the research that I did I found that most people were replacing parts left and right to try and make the code go away throwing away tons of $$$ on parts that didn't need to be replaced.

Some causes are:

Dirty or malfunctioning MAF
Vacuum Leak
Exhaust leak
EGR
DFPE
Intake Leak
Poorly seated dipstick
etc
etc

I rarely drive my car so the problem could be from a number of different events that happened over the span of 2 weeks. Over the course of 2 weeks I washed/detailed my engine, removed my air filter (cleaned and oiled it), dragged my exhaust on a driveway, accidentaly touched the MAF with a rag, and checked my oil. This means that everything that could have happened during this time matched most of the causes of the DTC coming up.

To solve the problem I started going down the list. I cleaned my MAF and it didn't work. I checked my exhaust and it didn't have a leak. I removed the DPFE sensor and there was no moisture in it. My last step was to grab a can of carb cleaner and start looking for a vacuum leak.

This is what I found..

The PVC hose rubs against a metal hose behind the S/C and wears it down until it puts a hole in it.

The PCV hose removed. It is in a hard to reach spot so if you have sausage fingers it may pose a problem. Even though I put it all back together and it looked fine, it was leaking so I put on a hose clamp. Problem solved. The hose retails for $10.98

While spraying around with carb cleaner I found more leaks. These hoses looked secure and leak free, but they were not. This is the PCV going into the back of the S/C. I put a hose clamp on it and it stopped leaking.

I found even more leaks. This is below the JLT intake tube after the MAF. The plug was torn on the inside where I couldn't see it. Again, it looked fine but it wasn't. I replaced it and all is well. The sensor under the intake was also coming out of the intake. I pushed it back in and it stopped leaking.

I highly recommened that everyone grab a can of carb cleaner and start spraying around all the vacuum hoses. Even tho the hoses look secure and leak free, they probably aren't. Your computer will correct tiny vacuum leaks but once they get to severe the computer will give you a DTC. Since fixing the vacuum leaks I have noticed that my car no longer stumbles and idles better than it ever has. I also noticed that hose clamps are your friend

 

[EvilBlack]

Great points. I need to go through and do this since I have only owned the car a couple of months and this is one more way to get to know the car better and verify/fix vacuum lines and leaks.

 

[Jimmysidecarr]

GREAT POST!:rockon::beer:

Another effective vacuum leak finding tool is a propane torch that is flowing but unlit.

The propane raises the idle just like the choke cleaner fumes do when you put it near the leak. It won't lift paint though.

Both present a very real fire risk that should not be ignored, but both are also industry standards for rapid location of a vacuum leak, and have been in use for multiple decades.:thumbsup:

If you know you have a coil boot leaking spark, you might not want to spray on it.

 

[spitin venom]

I started looking for the leak with propane but didn't feel safe. I found the carb cleaner worked better for me. Haha

I was going to post this in engine/tuning but figured it would get more exposure in terminator talk.

 

[Bdubbs]

Nice work. Wow that hose looks really bad. Is there a better quality hose that can be purchased which with stands heat better? So do you just spray carb cleaner around the hoses? When done wipe off with a rag? I'm not to comfortable with flammable products,lol.

 

[sneakysnake03]

With these cars getting 8 years old I think we are going to start seeing alot of those hoses going bad especially the PCV hoses with a oil going through them. They swell up and pop off or just deteriate like the one you had.

 

[Jimmysidecarr]

I started looking for the leak with propane but didn't feel safe. I found the carb cleaner worked better for me. Haha

I was going to post this in engine/tuning but figured it would get more exposure in terminator talk.

Not a ton of posts but 52 views already.

This sub forum is rocking pretty good now and seems to get better every week.

It's a good thread. And it will come up in a vacuum leak search.

Still on page one.

TTT:beer:

 

[spitin venom]

Nice work. Wow that hose looks really bad. Is there a better quality hose that can be purchased which with stands heat better? So do you just spray carb cleaner around the hoses? When done wipe off with a rag? I'm not to comfortable with flammable products,lol.

Thanks! I do not know of any hoses that are better from Ford but I am sure that you could make one using a different company. It is just a simple little 3" rubber elbow.

Just grab a can of carb cleaner and start spraying the vacuum hoses. I just used little sprays on the end of the hoses and listened for the idle to change. I kept hearig the idle change when I sprayed behind the supercharger so I started singling out the hoses and found the problem.

 

[spitin venom]

Not a ton of posts but 52 views already.

This sub forum is rocking pretty good now and seems to get better every week.

It's a good thread. And it will come up in a vacuum leak search.

Still on page one.

TTT:beer:

Thanks! One of the main reasons I made the thread is because when I searched multiple forums/websites about the DTC nobody had any detailed answers on what fixed it. I figured if someone gets in the same position I was in and ends up doing a search, this will help them.

 

[03cobra#694]

Good thread. I`m down about 2 in. vac right now and I suspect my oil separator. I`ve found a vac leak there before.

 

[mmustangsrus]

thanks for the write up !!! :rockon:

 

[01trublue cobra]

sub

 

[d3mon_fx]

duuuuuuude, you are my hero, i've been trying to hunt this code for a while, first i cleaned the MAF and that worked but right after i went WOT i had the code again, everywhere i went told me O2 sensors, lucky for me i decided to check here first, checked for leaks and boom same place same hose, thanks for the pictures those nailed it.

 

[01trublue cobra]

Thanks! One of the main reasons I made the thread is because when I searched multiple forums/websites about the DTC nobody had any detailed answers on what fixed it. I figured if someone gets in the same position I was in and ends up doing a search, this will help them.

Where did you buy that PCV hose that was burnt through? Ford dealer?

 

[TVSCobra]

nice work. I'm lucky I have access to a smoke machine for leak testing. Makes it very easy to find leaks.

 

[d3mon_fx]

Where did you buy that PCV hose that was burnt through? Ford dealer?

Got one at auto zone, was long so I had to cut it, the packaging was green and it said ford pcv connector was $20 tho

 

[Stiffy06]

Just had this code pop up on me earlier today. Thanks for the insight. Btw u can also use a spray bottle with water to find the leak. It will start bubbling at the source of the leak. It may not b as effective but its sure as hell alot safer

Sent from my Droid using Tapatalk

 

[Co-brat]

wholly shit man, ive had this damn code popping up on my car for like a year and could never figure this shit out. well now I know what im doing on the next nice day when I can work on my car. Question: was your car idleing like crap before you did this? like would it tend to want to hang up near 1000 rpms when you came to a stop at a light?

 

[KJ Hoppus]

I don't have the code but it seams worth checking considering all that you found. Good info.

 

[piss&vinegar]

Spitin Venom,
Thanks for posting this. It led me to find both of those hoses were bad. The one from the valve to the T and the one from the T to the plenum. I should not be getting the p0171/p0174 code again according to the data I logged.