Ford V10 OBD code

[30sweeds]

2001 E450 V10.Check engine light came on,scanned it and it comes up P0174,lean on bank 2.I checked in to this and it seems there are quite a few problems that could cause the code.Before I start throwing parts at it,my question to you guys....Is there 1 or 2 things that are most prevalent to cause this? Otherwise,I'll just be shooting in the dark. Thanks!

[allbrandauto]

PO174 is for running lean on bank 2 if it also had a po171 it may have a bad mass air sensor. but in your case you probably have a intake manifold gasket sucking air on bank 2 when cold

[30sweeds]

It is an OBD2 processor.The RV has 50 k miles.There are no drivability issues whatsoever.I have dealt with numerous exhaust leaks and exhaust manifold problems in the past and you can usually hear an issue if that is the problem.There was a vacuum leak in the reserve tank for the HVAC but was repaired a year ago.As stated,that would indicate a lean condition on both banks IMO.I will replace the O2 sensor,clean the mass air,and check the intake for leaks and see where that goes.

[theoldwizard1]

Gdetrailer wrote:
Depends, O2 sensor is considered a "wear item", but not always the issue with a lean code.

Concur !
OEM (Motorcraft) sensors are kind of pricey. The Bosch replacement one work well and cost less, especially if you buy them online (Rock Auto or Amazon). It is definitely a shot from the "parts cannon", but not to expensive and easy to install.

Gdetrailer wrote:
The typical problem areas with the Modular engines which causes the lean codes is vacuum leaks ...

Concur, again !

These can be difficult to trace down. Don't be surprised if you find a broken exhaust manifold. Common on Modular/Triton engines and could be causing the lean code.

[Gdetrailer]

MitchF150 wrote:
It's a vacuum leak! It's not any sensor.

While I agree it is most likely NOT a sensor, I do not agree that is is 100% a vacuum leak. The vacuum leak would have to be coming from the intake manifold on the same side as the Lean code.. Otherwise most likely would get lean codes for BOTH banks.

Most of the vacuum ports are located directly under or at the throttle body so most likely a vacuum line leak would affect both banks. Although it is not unheard of having a crack in the intake manifold..

More likely the exhaust manifold gasket or cracked exhaust manifold on the affected bank which is quite common on these engines..

Just had this same issue with a 2006 5.4.. Quite a job to change, generally pretty good chance multiple manifold studs will break off in the process.

We were quoted $800+ for one side, decide truck was not worth dumping that kind of money into, bed rails were rusted out, had to fix the front one just so bed was not laying on the frame.. Cab corners were showing signs of rust from inside, doors were nearly rusted through.. The lean code basically made it a easy choice to buy a 2020 and be done with the money pit..

Personally, even though for its time the V10 was a good engine, I personally feel it IS a money pit if it is in a pickup truck to continue to dump gobs of money at it. If you are DIYing the repair, you can easily end up going down a rabbit hole at a lower cost but it is a diminishing return on your money on very old outdated engine and transmission technology.. Not to mention working on these engines with the cramped engine compartment makes repairs take much longer to complete repairs..

The 2020 6.2 can and will easily replace a 2001 V10 in pretty much all cases and do it with a little better fuel economy..

If OPs V10 is in a MotorHome, well that is an issue that they will need to fix unless they wanted to replace the MH..

[MitchF150]

It's a vacuum leak! It's not any sensor.

[Gdetrailer]

DrewE wrote:
From what I understand, the O2 sensors do wear or drift in their output over time and with use, so replacing them even if it doesn't solve the problem is hardly money wasted if they're the original ones.

Depends, O2 sensor is considered a "wear item", but not always the issue with a lean code.

OPs vehicle may only have OBD1 system with OBDII port, meaning it has pretty limited information and sensors tracked in the system. May also have only upstream O2 sensors.

The typical problem areas with the Modular engines which causes the lean codes is vacuum leaks caused by vacuum lines cracking or breaking, damaged/leaking exhaust.

Being the lean code is only on one bank, vacuum lines might not be the issue.

However, the Modular series has one major shared flaw, the exhaust manifolds cracking, exhaust manifold studs breaking off or exhaust manifold gasket seal going bad creating a leak between the head and manifold.

If you can hear a exhaust "tick" or exhaust seams to have gotten much louder than it used to be especially when cold that would be the most likely cause of the lean code on that one bank.

Any exhaust leak before the Cats can dilute the exhaust stream causing a false O2 level which would indicate a lean condition. The fuel trim then will be increased until it maxes out and when that happens the CEL light and lean code is set. That bank will now be running too rich and you should be getting a rich fuel smell from the exhaust.

If it is a 4 O2 sensor system only the UPSTREAM (before the Cats)sensors are used to calibrate the fuel system to set fuel trim for lean/rich, the downstream (after Cats) are only used to check the Cats efficiency levels and those are different codes..

OP needs to fix it quickly before the Cat gets contaminated from excessive fuel..

If the engine was newer OP could track the o2 sensors and fuel trim settings which would be helpful in diagnosing but like I mentioned, 01 most likely does not have OBDII enhancements.

One could toss an O2 sensor at it and hope for the best, they aren't all that expensive, around $40-$50 but they can be a royal pain to change.

[DrewE]

From what I understand, the O2 sensors do wear or drift in their output over time and with use, so replacing them even if it doesn't solve the problem is hardly money wasted if they're the original ones.

[STBRetired]

Had a P0171 code (bank 1 instead of bank 2) on my 1999 V10. Turns out the O2 sensor had a small hole rusted through it where it was screwed into the exhaust. Replaced the sensor, easy and cheap fix.

[PastorCharlie]

https://www.carparts.com/blog/p0174-system-too-lean-cylinder-bank-2/

[K_Charles]

Cleaning the mass airflow sensor would be a cheap start.