P0442 Fault Code | Ford Explorer Forums - Serious Explorations

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P0442 Fault Code

Dave A

August 3, 2008
Reaction score
City, State
Milwaukee, WI
Year, Model & Trim Level
2006 XLT
Well my check engine light came on this morning. Everything continued to run fine.
Stopped to have the code scanned at the parts store after work and they came up with the P0442 (evaporative emission system)
Possible causes:
1 Defective or loose fuel cap
2 Evap canister hose cracked or not connected
3 Purge vent solenoid defective
4 Vacuum leak at engine

I'm trying the obvious first and have replaced the fuel cap.
How long until the system should reset if that was the problem?

I inspected the rest of the system and ruled out the cracked or disconnected hose, vacuum leak.

If the cap doesn't do it has anyone had to replace any of the other components?

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I have replaced many evap vent solenoids but this may not be your problem you can check it with a vacum pump and wire the solenoid to power to close it and see if it holds the vacum this is a large leak and it may have been cap but the code will not clear until it runs a evap monitor and it passes the test this is unpredictable when it will run this test but it will not run with a full tank of fuel or less than 1/4 hope this helps

The emission monitor has to go thru a couple of drive cycles before the code will reappear if the fault was not corrected. Assuming you had them clear the code.
A drive cycle can consist of steady driving (throttle) of approx. 15 minutes at 40 to 60 mph. Air temp above 40 F and IAT temp below 100 F. So find a long stretch of back roads with no hills, stop signs, etc.
Hope this info helps.

I wasn't able to get the code cleared when it was read.
I did take a 500 mile trip this weekend but the code remains. I'll have to check into the solenoid.

I had the code cleared yesterday. So far the CEL hasn't come back on.
The only thing that was changed was the gas cap.

I had the code cleared yesterday. So far the CEL hasn't come back on.
The only thing that was changed was the gas cap.

Chances are that you solved your problem. Is the cel does not reappear after 2 or 3 days of driving, then you are good to go.
The EVAP emissions system is very complex and difficult to diagnose. I chased code P0442 on my 99 for several months replacing parts (gas cap x 2, purge solenoid, hoses) only to find out that the steel pipe that the cap screws into has a plastic liner that was slightly cracked and would leak vacuum during the drive cycle test. Fix was to fill cracks with epoxy.
I got off lucky, could have been an expensive bill for someone else to chase down and repair.
And my 06 does not have a plastic liner inside the steel pipe, so this should not be an issue on my 4th gen.