Evaporative Emission System | Leak Detected


•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 leaks in the EVAP system
•Faulty vent o-ring seal

Normally there is no drivability issues, but your computer may be trying to compensate and that might make it run rough.

 The most common cause for the 442 on the code "X" (OHV) engine is the EVAP Canister Vent Solenoid/Valve (will not fully seal)! Trouble code P0442 is a code indicating a small leak (0.040").

If the PCM was not activating the CANV solenoid, the PCM would likely set a P0455 code instead, indicating a large leak. The PCM only activates the CANV solenoid during specific operating conditions when it wants to perform the Evaporative Emission (EVAP) system monitor leak test.

 This will only occur once per drive cycle provided that conditions are right to activate it To test; Access the Canister Vent (CANV) solenoid on the carbon canister. Ground the Violet/White (VT/WH) wire and check to verify that the solenoid is mechanically closed, by attempting to blow through it.

 Normally there are no driveability issues with EVAP related problems.
 (Yet if there is a vacuum leak due to a purge solenoid or vacuum hose there will be!)

Ford Explorer P0442 Code Symptoms

The P0442 code on a Ford Explorer will often be thrown after the engine has a hard time starting after refueling. I’ve personally had this problem happen to me. You’ll fill up the vehicle and it just won’t start. Then, it’ll either start on the second try or after cranking the engine for a while.
If you’re old enough to have driven a carbureted vehicle, the old stomp the gas and crank the engine method does actually help start the Explorer.
Other than the difficulty in starting, the P0442 doesn’t seem to cause any other problems (at least in the short-term). You may also smell gas when driving.

Ford Explorer P0442 Code Defined

P0442 is a general OBDII trouble code, which means it has the same meaning regardless of who manufactured the vehicle. The code technically stands for:

Evaporative Emission System | Leak Detected

The EVAP system captures all fuel vapor from the fuel tank and sends them to the engine’s intake in order to be ignited in the normal combustion process.
When the Ford Explorer’s computer detects that the EVAP system is not holding any pressure, it will throw the P0442 code.

Ford Explorer P0442 Causes

There are many things that can cause the P0442 trouble code on the Ford Explorer. The most common problem is far and away from the first one listed below.

• EVAP Canister Purge Valve– The most common culprit with the P0442 trouble code and the Ford Explorer is going to be the vapor canister purge valve. When it goes bad, it typically causes issues with the vehicle’s idle speed. This is especially true right after you fuel up. It’s really easy to replace. There are a few clips that you need to find and remove. There’s a great YouTube video on diagnosing the problem below, as well as how to replace the part. It’s fantastic. This is almost always the problem. They are really cheap on Amazon too. Always make sure to verify the fit for your vehicle. There’s a tool to check the fit right there.
• Fuel Vapor Hose– A leak in the fuel vapor hose that leads from the fuel tank to the intake will definitely throw P0442 in your Explorer.
• Gas Cap Bad– A bad fuel cap can cause the P0442 code to be thrown for sure. The Explorer will typically be warning you to tighten the fuel cap. This is a great place to start. It’s a simple thing to fix and only takes a few minutes to swap a gas cap.
• Loose Gas Cap– A loose gas cap will also trigger this trouble code. So if it’s the first time that you have experienced this issue, you may want to go ahead and tighten the cap and see if the code clears itself. Just be aware that it may take the engine several cycles to clear the code.
• Fuel Tank Pressure Sensor– If the fuel tank pressure sensor has gone bad, it can cause all sorts of problems, including the P0442 code.
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  P0442 FORD - Evaporative Emission System Leak Detected Small Leak

         

  Possible causes

• Missing or loose fuel cap
• Incorrect fuel filler cap used
• Fuel filler cap remains open or fails to close
• Foreign matter caught in the fuel filler cap
• EVAP canister or fuel tank leaks
• EVAP system hose leaking
• Fuel tank leaking
  What does this mean?

Tech notes

The P0442 code means that the control module has detected a small leak in the Evaporative Emission (EVAP). Loose fuel tank filler cap is the most common cause that triggers the P0442 code.


What does this mean?

When is the code detected?

Malfunction is detected when the EVAP control system has a leak, the EVAP control system does not operate properly.

Possible symptoms







Engine Light ON (or Service Engine Soon Warning Light)

Possible a noticeable fuel odor caused by the release of fuel vapors


P0442 Ford Description
The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for the following conditions:- Large and small leaks
- Excess vacuum
- Purge flow during non-commanded conditions
- Fuel Level and Fuel Pressure sensor faults
- EVAP Purge and Vent Valve faults

The ECM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The ECM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the conditions are met in order to apply an engine vacuum to the EVAP system. The ECM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. This test verifies if a vacuum can be achieved in the EVAP system. Failure to develop a vacuum may be caused by a large leak or a restriction.