Hello all,
I am new to the forum, and must say right away I am NO mechanic, but can follow directions and work on simple jobs. I recently inherited, from my wife's grandfather, a 2001 Ford F150 "Legend" edition truck with 58,821 original miles on it, it has a Triton 5.4 V engine. It's my first truck (after driving compact cars for about 40 years), and my first Ford. I like it alot.

Recently, the "service engine soon" light came on, error code #P0442...after doing a little research, I learned the gas cap can be the problem most times, so I bought a new one, had the error code cleared, and all was fine...for about a week, now the light is back on, same error code. The first time I pulled a code, a friend here at work did it for me, the second time, I had it done at AutoZone...they gave me a printout with the error code, and a description that reads "Code: P0442 indicates that the Evaporative Emission System had a small leak for a predetermined period of time"....."had"?...not sure what that means, maybe it's just how they word it.

I have read a bit on this forum about this particular error code, and understand that it could be a leaky hose somewhere, and the best way to find it would be to have someone run a "smoke test" on the evaporative emission system...and I've also read that some after-market gas caps don't seal well, to use an OEM gas cap...so now I'm wondering if maybe the one I bought (from Amazon) isn't holding a seal well...I KNOW the old one wasn't, it didn't even "click" when tightened, and was very loose, even when tightened...the new one clicks like it should, and tightens well...but I have some doubts about it sealing correctly...I can post a link here to the one i bought, if that is allowed on the forum

Is having the "smoke test" done at a shop a pricey job?...is there any other thing I can visually inspect before investing in that?...I've read there's lots of hoses on this truck, and a small leak could be in many different places...and finally, am I harming anything by driving the truck while this issue exists?...it runs great, when I first got it, had new new spark plugs and boots installed, new brakes and tires, a couple of the ignition coils replaced, and a few other minor things.

Wife's grandfather lives at the beach (I'm in Texas), so for the truck was used there for some years before I got it, and was exposed to salty air all that time, maybe that contributed to premature hose rot, I'm not sure...sorry this post is so lengthy, just wanted to include as much info as I could.

Thanks in advance for reading, and any advice you guys may have to offer.

Matt

 

When you had the code cleared the system did a new test of the whole system and found the same leak again.
The EVAP system take a lengthy amount of time as you saw.
It does a two level leak test.
There are hoses, solenoid valves and a sensor involved.
Unless a good shop takes the time, I do not think a smoke test will show it up. It may not be a slow leak to the outside world where it can be seen.
No problem using the truck until the leak is found and repaired.
Remember the retest takes a number of drive cycles because it's a complicated test.
Good luck.

 

Thanks very much for the reply and info, Bluegrass 7

May I ask what you mean by "The EVAP system take a lengthy amount of time as you saw.
It does a two level leak test."

I am a complete newbie to OBD testing...what "length of time" do you refer to?...the friend at work who had his own code reader retrieved the code within a few minutes, as well as the employee at Auto Zone...friend at work cleared it, a week later, SEL came back on, and that friend was out of town, so I used AZ's free check

Also, what do you mean by "retest?...if I were to have my friend at work "clear" the SEL warning light, would that have anything negative/positive to help with the situation, and warning light?

Again, thanks for the help, much appreciated

 

Anytime a Clear' is done, it causes the computer to go into full system diagnostics.
Anytime power is removed, it clears all codes, centers any variable tables built from driving as well as entering the full diagnostics.
The Evap system is a series of tests done at different times along with tests of 6 other systems.
The Evap system takes the longest because of it's length and complexity.
The EVAP system is comprehensive test done and mandated by federal law to be sure fuel vapors are not released to the atmosphere but burnt in the engine.
You will not see a code for any system until the tests are al complete on that specific system and a test failure has occurred.
If the same codes comes up again, the original fault has not been cleared.
When either cause of diagnostics are entered , a code P1000 is set until all systems pass then the code 1000 clears..
This code does not light the CEL and may not be registered on many code Readers, only on Scanners each time.
Good luck.

 

First off, do you have mandatory emissions testing in your area? If not, then it's probably appropriate to lower your stress level about the issue (unless you are inclined to do so anyway). If you do have E-testing, then learn what your available incomplete monitors can be. Usually, for that old of vehicle, you're allowed two "incomplete" monitors and you can still pass the test and get plates.

If your replacement gas cap wasn't a Motorcraft, do it over and get one. Reset the system and allow it to run its monitors as you drive normally. Make sure you inspect and clean the sealing surface of the gas filler tube so the cap can seal properly to it.

The entry conditions for the EVAP monitor are somewhat narrow. It might be only a few days, a few weeks weeks, or months (in certain conditions, even) before they execute.

 

Thanks very much to the both of you for the prompt and informative replies, it is much appreciated.

projectSHO89, I DO NOT have emissions testing in where I live, but I DO tend to stress over things like this, so thanks for the comforting words, lol.

Here in Texas, we are required to first have vehicles inspected before we can purchase registration (my registration tag expires in June)...I have read that if the SEL is on, you cannot get your vehicle inspected...not sure if that is correct, or if it depends on where you live.

The gas cap was not a Motorcraft, it's a "Stant" brand...I'll look into getting a MC one ASAP...by "reset the sytem", do you mean have the warning light cleared, or remove the neg. terminal on the battery for 10-15 minutes?.....resetting my radio stations and clock is no big deal, even I can do that, if that is all that will happen by disconnecting then reconnecting the battery.

"The entry conditions for the EVAP monitor are somewhat narrow. It might be only a few days, a few weeks weeks, or months (in certain conditions, even) before they execute."---can you clarify this a bit for a total newbie?

Again, thanks very much for the help

 

Depends on what is being inspected, safety or emissions. A MIL is not considered to be a safety concern, that inspection would focus on mechanical things like lighting, brakes, lights, tires, etc.

Either works. You could also remove the PCM KAM fuse and that means the radio won't need to be reprogrammed. If your battery cable ends and terminals need servicing, might as well just do that and the PCM will be reset at the same time.

Entry conditions - can't be too hot, too cold, not enough gas in tank, too much gas in tank, other monitors have to have passed successfully, etc.

 

Thanks again!...I'll need a safety inspection, no emissions testing where I live

Removing the fuse sounds like the easiest way to reset the system (once I have the new gas cap)...aren't those fuses numbered, and if so, do you happen to know what # that fuse is?

I would remove the fuse, then replace, while the truck is running or not running?...or does it matter?

Thanks for the info on the entry conditions

Here's the cap I'll be ordering, Amazon indicates it should fit my make/model, hope they're right:

 

Fuse F2 under the dash. Remove it for 10-15 minutes with the ignition switch in the OFF position. That should reset the KAM.

 

Thanks again

The new Motorcraft gas cap will not arrive until next week ("free shipping" sometimes has it's limits)

Should I try it with the knock-off (but new) gas cap I have now, just to see what happens?

Can't hurt anything, right?

 

Removed the fuse, will give it 30 minutes, then replace and start the truck

 

For the record, here's a pic of the fuse box, the one I removed (hopefully the right one) from the slot just below the top upper left one marked "ST."

 

It worked, the SEL is now off!.....now, let's see how long it STAYS off, lol

Thanks again for the help, projectSHO89 and Bluegrass 7...very much appreciated

I have a feeling I'm going to like it here, I have a few other minor issues I'd like to discuss, and am looking forward to learning more about my "new" (to me) truck

I'll post on this thread again when/if the light comes back on, and definitely when I replace the gas cap with the recommended one next week

Cheers all, have a great weekend

 

Got the new gas cap in yesterday, and got it on the truck,,,oddly, it doesn't "click" when tightened, though it's 1/4 turn, like the last ones...and you have to push it down, then turn...seems like that's a good thing, makes a tight seal.

SEL light has not come on since Friday, when I pulled then replaced the fuse, but from what I understand from the posts above, the truck will be "self-testing" for q while during normal driving conditions...it's running fine, I'll keep an eye on things

 

A note;
The system will go into a full diagnostic if a code clear is done. This full diagnostic is what takes the longer time.
When filling tank with gas, the system knows the cap has been taken off, so treats it differently so the fuel gauge reading is updated 'only' and does not go into diagnostics again.
I does however keep track of how long the tank goes without proper pressure sensor feedback to detect a loose/leaking/missing cap.
A lot goes on most are not aware of.
Good luck.