P04F0 code - Evap System problem

[mdformula350]

Anyone have any updates on this?

Keep on getting the codes, usually during 1/4 tank of gas and driving on highway / cruising speed.

Don't want the dealer to take my money to diagnose the code and it may or may not be under warranty according to them.

thanks.

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[kduff44]

My check engine light still has not come back on since replacing Fuel Vapor Separator Tube (KB3Z-9D289-B), Vapor Vent Solenoid (9U5Z-9F945-C), and Fuel Vapor Tube (KB3Z-9K318-A).

And these were replaced under the emissions warranty. Unfortunately this code could be a variety of things in the evap system so its not a sure thing it'll be covered under the emissions warranty.

 

[Alaska Wolf]

My check engine light just came on earlier today at exactly the same moment I hit 966.0 miles. Coincidental I'm sure. A few miles later, the Tow Mode indicator suddenly came on as well for no apparent reason. Swung by the Quick Lane and they checked the light for me and said it was throwing the P04F0 code. I hadn't filled up recently, truck was at 3/4, so not sure what happened.

 

[Superdannyboy]

I had that code a few times for evap leak. My capless fuel filler was dirty and prevented the little door that the gas pump nozzle goes in to close properly. Cleaned it with a damp cloth and it was gone. I don't have the stock bedsides tho my bedsides are fiberglass and I didn't extend the filler to the little gas door so it gets dirty and I wipe it.

 

[Trustable]

you said emissions warranty, is that included in the powertrain warranty or something different?

 

[Alaska Wolf]

you said emissions warranty, is that included in the powertrain warranty or something different?

Ford's Emissions Warranty is separate and is valid for eight years or 80,000 miles, whichever you get to first.

 

[Trustable]

Ford's Emissions Warranty is separate and is valid for eight years or 80,000 miles, whichever you get to first.

Never knew, thanks!

 

[Alaska Wolf]

After originally replacing the Fuel Evaporative Canister - Ford (GD9Z-9D653-A) which cleared the P04F0 code, my Ranger coded with the P04F0 code again after another 500 miles. Took it back into my dealership and once again Ford's diagnostics declared the just replaced Fuel Evaporative Canister as being the issue yet again. Neither my tech nor service advisor think that's the problem so they've bumped the issue up to Ford engineering division. Guess we'll see what happens.

 

[quangdog]

After originally replacing the Fuel Evaporative Canister - Ford (GD9Z-9D653-A) which cleared the P04F0 code, my Ranger coded with the P04F0 code again after another 500 miles. Took it back into my dealership and once again Ford's diagnostics declared the just replaced Fuel Evaporative Canister as being the issue yet again. Neither my tech nor service advisor think that's the problem so they've bumped the issue up to Ford engineering division. Guess we'll see what happens.

Did you get an answer on this? 2 Days ago while accelerating moderately up to 40 from a stop light, the CEL came on. I had 3/4 tank of fuel at the time. I pulled over and pulled 2 codes (I keep a small code reader in the truck):

P04F0: EVAP System High Pressure Purge Line Performance
and
U0422: Invalid Data Received From Body Control Module

I noted the codes, but was several miles from home and simply cleared them to get rid of the CEL and drove home. This involved using up most of the rest of that tank, and filling up again, ultimately returning home with about a half tank yesterday. Today after work on my way across town I had the CEL light come on, this time with a little less than 1/2 tank of fuel, again accelerating moderately from a stop light. I again pulled over and checked the codes: They are the same as the day before.

Does the combination of these 2 codes point to something more specific than just "something in your emissions... "?

 

[airline tech]

You are going to need a evap test to be done to pinpoint down to exact, and if you have a scanner that is capable of running a EVAP test you can do it. I don't think Forscan will do this.
You need to be able to command the EVAP purge valve closed and open and monitor FTP sensor voltage. while testing.

This EVAP leak test is done once per drive cycle (automatically) (Drive Cycle-Test) if it fails the test the check light will kick on.
The related code U0422 is because the test cannot be completed. (Invalid Data)

Unfortunately, the EVAP system absolutely sucks to T/Shoot , I have a smoke machine that comes in handy for that hard to find leak.
Bear in mind that this a general code and EVAP system test can be difficult to pinpoint, mainly leaks

My experience most likely would be a stuck open / closed purge valve or vent valve but the Ranger has a more advanced system than I have worked with in older vehicles.

P04F0 - EVAP System High Load Purge Line A Performance

Description:​

The EVAP check valve test is performed during minimal boost conditions, once per drive cycle, when entry conditions are met. This DTC sets when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (single path check valve), or when the fuel tank vacuum is less than a calibrated amount within a specified amount of time or when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (dual path check valve).​

Possible Causes:​

Incorrect EVAP system hose or line connections Restricted EVAP ejector connections at the intake air system Stuck open EVAP check -Valve Stuck closed EVAP check -Valve Damaged EVAP ejector Damaged EVAP check -Valve

 

[airline tech]

FYI
One little note for those that wonder (What the heck is that POP sound?)
If you ever are driving and you hear a Pop or Knock (Single) just behind you and sounds like a rock being thrown off the LR tire into the wheel well. You are hearing the Evap Canister Vent Valve Solenoid closing, this is an indicator the system is doing a automatic EVAP test.
At this point the Evap Purge Valve opens, to pull a vacuum on the system and tests for decay, if it fails this decay test (leak) or registers increased vacuum (blockage) then the test fails, and light is illuminated.
It uses the Fuel Tank Pressure sensor as a reference. (via voltage reading on the sensor)

 

[quangdog]

You are going to need a evap test to be done to pinpoint down to exact, and if you have a scanner that is capable of running a EVAP test you can do it. I don't think Forscan will do this.
You need to be able to command the EVAP purge valve closed and open and monitor FTP sensor voltage. while testing.

This EVAP leak test is done once per drive cycle (automatically) (Drive Cycle-Test) if it fails the test the check light will kick on.
The related code U0422 is because the test cannot be completed. (Invalid Data)

Unfortunately, the EVAP system absolutely sucks to T/Shoot , I have a smoke machine that comes in handy for that hard to find leak.
Bear in mind that this a general code and EVAP system test can be difficult to pinpoint, mainly leaks

My experience most likely would be a stuck open / closed purge valve or vent valve but the Ranger has a more advanced system than I have worked with in older vehicles.

P04F0 - EVAP System High Load Purge Line A Performance

Description:​

The EVAP check valve test is performed during minimal boost conditions, once per drive cycle, when entry conditions are met. This DTC sets when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (single path check valve), or when the fuel tank vacuum is less than a calibrated amount within a specified amount of time or when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (dual path check valve).​

Possible Causes:​

Incorrect EVAP system hose or line connections Restricted EVAP ejector connections at the intake air system Stuck open EVAP check -Valve Stuck closed EVAP check -Valve Damaged EVAP ejector Damaged EVAP check -Valve

Thank you for the info. What a PITA to troubleshoot.

 

[Alaska Wolf]

Did you get an answer on this?

I did, maybe. Ford's diagnostics kept passing all areas of the emissions test tree so neither the tech, nor Ford apparently, were able to isolate down to an exact bad component. The tech ran through the emissions tree several times but kept ending up with the same result, with the previously changed Fuel Evaporative Canister being bad again. After having the truck for a week, Ford had them replace the evap ejector and a hose and clear the code. Sounds a bit like old school shotgun troubleshooting to me, but so far it hasn't re-coded; but I'll reserve judgement until its gone a few weeks without coding. It does sound a bit like Ford emissions diagnostics may need a little tweaking to me though.

 

[quangdog]

Knowledge is power, and on a complicated system like EVAP, troubleshooting is always going to start with understanding how the system works. I found this guide to be very helpful in teaching me how the components all work together:
https://www.motor.com/magazine-summary/fords-evap-system-operation-testing/

I have not tried It yet, but I've read this morning that Forscan has the ability to test each individual component, but not to run a full EVAP test like the Ford techs can at a dealer. The best suggestion I've found so far is to start by understanding the system, then use Forscan to real-time monitor each of the components in the system while driving around trying to get the code to trigger. If you can catch the test as the vehicle runs it, while monitoring each component in Forscan, it should be easy to identify which specific component has failed.

Still - pain in the arse to troubleshoot.

 

[Alaska Wolf]

I've read this morning that Forscan has the ability to test each individual component, but not to run a full EVAP test like the Ford techs can at a dealer.

It does, but it was about as much use to me as Lithia's Ford diagnostics machines were to them. Considering quite a few of the Ford/Lincoln TSBs for this issue call for Ford techs to disconnect and reconnect every emission hose on the system, it makes me wonder. The article you found did give me a chuckle though, "If the vehicle has recorded a leak code, you’ll want to take the next step and begin shaking the evap system components while monitoring the in.-H2O gauge. If the gauge begins to drop, you know one of the components you moved around is creating the intermittent issues. If the needle quickly drops to atmospheric pressure, you have a large leak and need to search for it with the smoke machine." We used to troubleshoot vacuum, and hydraulic, systems like that way back in the 20th Century (seems like a long time ago), only without all the high tech diagnostics.

I did find the bit about using "a space heater to accelerate the fuel temperature change process" a bit disconcerting though. Hopefully you aren't venting gasoline fumes... I've always figured using space heaters around something so volatile as gasoline was probably not the best idea.

But with all the articles and TSBs I've read through, removing and replacing all of the vacuum hoses actually seems to be the best idea. Removing and replacing vacuum hoses was usually always the first step in troubleshooting vacuum problems in carburated engines and systems. Interestingly, one Ford TSB I read acknowledged that none of the parts being returned to Ford for testing actually tested bad; but, that kind of goes hand in hand with the Ford/Lincoln TSBs telling techs to disconnect and reconnect all of the emission lines.

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