The check engine light came on and when I hooked up the scanner it gave me the code for a small vaccum leak. I can't remember the code # right now I'm at work, but I do know that it was for the vaccum leak. Does anyone have any idea's where to start looking for this leak? The truck doesn't seem to sound or drive any different. By the way it is an 02 f150 4x4 with the 5.4L.
Thanks

 

Most common "small leak" is a loose gas cap. Make sure you tightened it.

 

Thought it could be, because my 88 had that problem. However, it has been throwing this code for a while now and over several fill ups. It leads me to believe that it is not the cap. I will check it closer though and make sure the seal is still good... Any Other ideas? Thanks

 

What was the actual code? Maybe read or get it read again.

 

Check all vac lines around intake area.Check vac line to pcv valve.They are bad about swelling up and leaking.After repair,disconnect battery for a couple of minutes to reset computers keep alive memory.

 

Alright finally got the code P0442 EVAP emission control system leak (Small).
I could be completely off base but I was told this was a small vac leak. Can anyone tell me what would cause this? If ya can could you be so kind as to tell me where this is and what the H#$% it would look like. Thanks for all the help and Merry Christmas

 

That can be like looking for a needle in a haystack.

P0442 - EVAP Control System Leak Detected (Small Leak)
The PCM monitors the complete EVAP control system for presence of a small fuel vapor leak. The system failure occurs when a fuel vapor leak from an opening as small as 1.016 mm (0.04 inch) is detected by the EVAP running loss monitor test.
1)After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
2)Small holes or cuts in fuel vapor hoses/tubes
3)Canister vent solenoid stays partially open on closed command
4)Damaged, cross-threaded or loosely installed fuel filler cap
5)Loose fuel vapor hose/tube connections to EVAP system components
6)EVAP system component seals leaking (EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve assembly)


Item Part Number Description
1 9030 Fuel filler cap
2 9C052 Fuel tank pressure sensor
3 9B593 Fuel vapor vent valve
4 9C915 Evaporative emission canister purge valve
5 9F945 Canister vent solenoid
6 9D653 Evaporative emission canister
7 9002 Fuel tank
8 9C015 Fuel vapor control valve
9 9189 Fuel filler pipe check valve
Evap canisters & vent solenoid.

 

As previously stated, check the PVC valve tubing. Especially where it connects to the rear of the intake manifold. It is a pain to check, but they tend to split and/or become oil soaked to the point they collapse when vacuum is applied.

 

So if the truck is still running fine is alright to drive till I get the time to find the leak? And also will this be enough of a leak that I can see fuel leaking, or is there an easier way to find this pain in the @$$ leak. Thanks for all the help you guys are a life saver.

 

Yes, it's OK to drive it until you have time to find the leak. You'll just have to look at that check engine light. There won't be any fuel leaking. This is a vacuum leak in the EVAP Control System, and a very small one at that.

 

02f250fx4,
Did you ever get this problem fixed? Hopefully so. If so, what was the problem?

Thanks,
Mike-G