» View Question
Jimm

Jimm 4/23/2011

1998 Ford Contour LX 4 Cyl 2.00L

Engine

Have code P0442 Evaporative emission system leak @ 0.020" or less. Beside the gas cap replaced with new OEM what else?

The car runs OK and after installing the new gas cap no code appeared for over one month. Now the same code P0442 is back. Besides replacing the gas cap with new OEM Motorcraft and making sure the filler neck and gasket are clean with a good seal - what else might I check to correct this code?

6 Answers


CVO

CVO 4/23/2011

This indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

A code P0442 most likely means one or more of the following has happened:

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal

Reply
0
HouseCallAuto

HouseCallAuto 4/23/2011

Replace the Evaporative Emissions (EVAP) Canister Vent Solenoid/Valve. The canister vent solenoid is a normally closed solenoid located on the charcoal canister in the left rear of the car. This solenoid is subjected to the road elements and has a high failure rate due to corrosion causing a slight leaking condition.

Reply
0
HouseCallAuto

Jimm 4/27/2011

HouseCallAuto - have an EVAP solenoid valve (PN CX1639) ordered @ $38 and change from RockAuto.com. Should be able to change out in a few days. I'll post the results. Thanks for the recommendation.

HouseCallAuto

Jimm 4/30/2011

Have replaced the EVAP solenoid valve, reset the adaptive strategy and no codes whatsoever. I'll know more if this has cured the problem of course after driving for more miles, but so far so good.

HouseCallAuto

Jimm 5/2/2011

The same code P0442 has returned. After a little over 210 code-free miles and after replacing the EVAP solenoid valve, and re-setting the engine control memory system - the same code P0442 has reappeared just today on my drive home from work. What is next?

HouseCallAuto

Jimm 5/15/2011

Now the code P0442 has disappeared without doing anything additional - no re-checking the gas cap, no cleaning the filler neck or seal area - just driving around 400 miles since replacing the EVAP system solenoid valve and resetting the memory. Looks like the code is gone for now - will keep monitoring to see if it may return.

Jimm

Jimm 5/21/2011

Well after some 400 or so code-free miles, the same code P0442 has reappeared. So now what? Any more suggestions as to what to check or how to fix? I've already replaced both the gas cap (new OEM) and the EVAP canister solenoid valve.

Reply
0
CVO

CVO 5/21/2011

Inspect the wiring terminals for the EVAP for any corrosion ( green stuff occurs from the copper). Use the WD-40 to clean the terminals and restore the conductivity.
For further information, visit this site
http://continuouswave.com/ubb/Forum6/HTML/001202.html

Reply
0
CVO

Jimm 5/23/2011

I've cleaned the EVAP wiring terminals and inspected for any signs of corrosion - none found

CVO

Jimm 5/26/2011

Are ther any other suggestions as to the P0442 code might be corrected? The EVAP canister soleoid wiring connection is free of corrosion. The gas cap is replaced with a new OEM grade, and the filler neck area and gasket is clean, so I suspect there's a good seal at this point. One site and response has suggested adding some petroleum jelly around the seal surface. I might try this - though this seems as a tempoary solution. Any thoughts?

CVO

CVO 5/26/2011

Maitre HCA. This post still needs HELP.

Reply
0
HouseCallAuto

HouseCallAuto 5/27/2011

You have done everything you could and you have done it in the correct order. Most times the solenoid is the cause, but not 100% of the time.
The only accurate way to diagnose this at this point is with a smoke machine (injects low pressure smoke into the EVAP lines and components and you will see where the smoke comes out, that is what it is for and why it exists because finding an intermittent slow leak in the EVAP system which could be anywhere is very difficult, one of the most elusive things to diagnose is EVAP leak codes, even the fuel pump o-ring seal can leak. Have a local shop do a smoke test and confirm the origin of the leak. Expect to pay about $100 for the test. The smoke machine cost is about $1000 to $1500.

Reply
0
HouseCallAuto

Jimm 5/27/2011

Thanks for the suggestion. I'll check to see if any of the local auto repair businesses use the smoke machine. I'm familiar with them, having tested and used one a couple years ago for project at work. I certainly don't mind the cost for the test - as long as the root cause(s) for the nagging EVAP leak are pinpointed. I'm really tired of resetting the memory and code only to have it reappear every 200-400 miles or so - thinking...'this time it may be fixed!'.

Answer this question

( characters left)

Follow Question

what's this?
advertisement
advertisement