Question about 2002 Ford Taurus

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An engine sign

I have a 2002 Ford Taurus, and an engine sign showed up. However, I pulled out the code which is P0442.

what is the problem, how much would that cost me and when do I need to fix it, can I wait for the next week, or its something that needs to take care of ASAP.

thanks,

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Hi,

This is intended to provide basic information about the P0442 fault code, what can and cannot cause it to occur, but also includes technical information for a better understanding of this code as well as the diagnostic procedures involved. This information is from our emissions expert and we suggest taking this to the shop if they are having problems diagnosing this code.

OBD II Fault Code:
P0442

Fault Code Definition:
Evaporative System Malfunction, small leak

Symptoms:

  • Check Engine Light will illuminate
  • In most cases there are no adverse conditions noticed by the driver
  • In some cases there may be a noticeable fuel odor caused by the release of fuel vapors

Common Problems that Trigger the P0442 code:
  • Defective or damaged Fuel Cap
  • Distorted or damaged Fuel Tank filler neck
  • Small tear or puncture in the Evaporative System hose(s) and/or Carbon Canister
  • Defective Fuel Tank Sending Unit gasket or seal
  • Small split in a seam of the Carbon Canister
  • Defective Evaporative Vent Valve and/or Evaporative Purge Valve
  • Defective or damaged Fuel Tank
  • Defective Fuel Tank Pressure Sensor
  • Defective Leak Detection Pump
  • Slightly loose and/or worn clamps or hardened o-rings any where in the Evaporative System
Common Misdiagnosis:
  • Fuel Cap
  • Evaporative Purge Valve
  • Evaporative Vent Valve
Polluting Gases Expelled:
HC’S –Hydrocarbons -> unburned droplets of raw fuel that smell, effect breathing and color the sky

The Basics:

The evaporative control (EVAP) system captures any raw fuel evaporating from the fuel storage system (e.g. the fuel tank, the filler neck, and fuel cap). Under precise operating conditions dictated by engine temperature, speed, and load, the EVAP system stores and purges these captured fuel vapors back into the combustion process.

Learn More:

The Evaporative Control System is designed to not only capture, store and purge any raw fuel vapors that leak from any areas of the Fuel Storage System but also to run a series of self-tests that confirm or deny the Operational and Vapor Holding ability of the System. This is an important task because at least 20% of the Vehicle produced Air Pollution originates from malfunctioning Vehicle Fuel Storage Systems. There are many ways for vehicles to 'leak test' the Evaporative System, but most perform the leak test either when the vehicle is sitting, say over night, or shortly after initial start up after the vehicle has been sitting over night. The Evaporative Systems operational performance is also tracked by the Power Train Computer by reading the change in the Oxygen Sensor voltages and Short Term Fuel Trim when ever the stored Vapors are released or 'purged' back into the combustion process. These values should indicate that fuel is being added to the system and that the over all mixture is getting richer. The purging process occurs when the vehicle is under acceleration, which is when most vehicles require additional fuel.


P0442 Diagnostic Theory for Shops and Technician

The Code P0442 indicates that there is a small leak in the Evaporative System, but this is somewhat misleading. What the code really indicates is that the Evaporative System will not hold a specified level of vacuum for a specified amount of time when it performs its leak test. Let's go over a little about how the Evaporative Leak Test is performed by the Power Train Computer. When the leak test is performed, on most vehicles, the vehicle must have been sitting for at least 4-8 hours in order for the Engine Temperature and Air Temperature to be identical. This is to provide a base line for the test because gasoline and diesel fuel are volatile fluids that expand and vaporize easily with warm temperatures. When the Leak Test initiates, the Vapor Canister Vent Valve is closed to prevent any fresh air from entering the Evaporative System. Then the Purge Valve is opened which allows the engine to create a vacuum in the sealed off Evaporative System. After a specified time interval, which is usually about 10 seconds, the Purge Valve is shut off and the vacuum level in the system is measured with the Fuel Tank Pressure Sensor. Then a count down initiates which measures the rate at which the vacuum decays in the system. If the vacuum decays faster than the specified rate on 2 successive tests, then the Power Train Computer will fail the Evaporative System for a small leak and set the code P0442. Most modern Evaporative Systems will fail the leak test and set a code P0442 with a pin sized hole anywhere in the Evaporative System, which amounts to 0.020 of an inch or ½ of a millimeter ( 0.040 ).

Continued...............

Posted on Oct 06, 2009

  • taran_2005
    taran_2005 Oct 06, 2009

    There are 2 other variations of the above Evaporative System Leak test that are commonly used:

    The
    Leak Detection Pump or LDP system uses Engine Vacuum to operate a
    bellows like pump to build vacuum in the Evaporative System once the
    Evaporative Vent Valve has sealed the system. The LDP has a diaphragm
    that changes shape as vacuum builds. When the desired amount of vacuum
    has been reached, the diaphragm opens a set of electrical contacts that
    disables the LDP and stops the vacuum from building any further. Then
    the system starts a timer and monitors how long it takes for the
    diaphragm to relax and the electrical contacts to close. If the
    diaphragm relaxes in less than the required amount of time and the
    points touch a bit early on 2 consecutive tests, a code P0442 is set by
    the Power Train Computer. The LDP system is common on Chrysler/Jeep and
    many European vehicles.

    The Stationary or Sitting Evaporative
    Leak Test uses the change in the Fuel Tank Pressure Sensor data as the
    vehicle sits, to determine whether or not there is an Evaporative
    System Leak. Once the vehicle is shut off for a pre-determined amount
    of time, the Power Train Computer closes the Evaporative Vent Valve.
    Then any pressure change in the Fuel Tank Pressure is closely
    monitored. Under normal circumstances, the pressure inside the Fuel
    Tank should decrease, slowly, as the Fuel inside the Fuel Tank cools
    off. If the pressure falls off a little faster than the maximum
    allowable rate for 2 consecutive tests, the system will set a code
    P0442. This type of system is used on many GM and Ford vehicles.

    Note:
    In very hot climates like Phoenix, Arizona, the Evaporative System may
    never run its monitor, because when the Air Temperatures stays over and
    around 100 degrees, the Fuel becomes too volatile and it is impossible
    for any Evaporative System to perform an accurate Leak Test.

    Now, what are some of conditions or components that will cause the Evaporative System to fail its leak tests?

    Here are some common tests for the Evaporative System:


    • Retrieve the code and then write down the freeze frame information
      to be used as a base line to test and verify any repairs. If there are
      any other Evaporative System Codes, then make special note of those as
      well because they may be triggering the P0442. Any Purge Valve or Vent
      Valve codes i.e. P0446, P0443 etc can also trigger a P0442. It is
      important to address these codes before you attempt to repair the
      P0442. This is because if the Vent Valve or Purge Valve is not
      functioning correctly, it may lead to a small leak that will set the
      P0442. The same applies to any Fuel Tank Pressure Sensor codes or Leak
      Detection Pump codes

    • Perform a careful and close visual inspection of all accessible
      hoses and components in the Evaporative System for any signs of damage
      or degradation that could cause a leak

    • Pay very close attention to the Fuel Tank Pressure readings by
      using a scan tool. Does the Fuel Tank Pressure Sensor work properly? If
      it does not, the system will think that insufficient vacuum is being
      created when in fact there is a sufficient amount of vacuum being
      created. The problem is the fact that the Fuel Tank Pressure Sensor is
      unable to precisely read it. The Fuel Tank Pressure Sensor is the
      primary feedback sensor that the Power Train Computer relies upon for
      valid Leak Test data

    • Inspect and test the Fuel Cap and inspect how well it fits onto the
      Fuel Tank Filler Neck. Ensure that the Fuel Cap Seal isn’t dry or
      cracked. If the Fuel Cap will not seal or hold vacuum and pressure,
      then it can trigger the small leak code P0442

    • Verify that the Purge Valve and that the Vent Valve work properly
      and hold vacuum for a sustained amount of time, at least 30-60 seconds
      with virtually no decay. If either one of these Valves function
      improperly, the system will never develop and/or hold the proper amount
      of vacuum. It is advised to energize both the Purge Valve and Vent
      Valve several times test their vacuum holding ability during and after
      each time they are energized. It is not uncommon for these devices to
      fail on an intermittent basis

    • If all the components seem to look and function properly, then the
      next test to perform is a Smoke Machine Test of the entire Evaporative
      System. This will usually root out any leaks that are hidden behind
      and/or under components of the vehicle. Pay close attention to the Fuel
      Tank Filler Neck, the Carbon Canister and the Fuel Tank itself,
      especially where the Fuel Pump and Fuel Level Sending unit are located
      and sealed. Occasionally when a Fuel Pump is replaced, the seal isn't
      replaced or properly installed. This can cause small leaks in the
      system. Occasionally one may have to remove the rear seats to further
      inspect and pinpoint the source of a Fuel Tank leak.
    Hope i helped you.

    Thanks for using ' Fixya ' and have a nice day!!


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What does that mean? 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
.
Symptoms You likely won't notice any drivability problems.
Causes 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
Possible Solutions With a P0442, the most common repair is to:
  • Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
  • Otherwise, replace the gas cap, or
  • Inspect the EVAP system for cuts/holes in tubes/hoses
You should be good till next week. If you smell gas though you might want it looked at ASAP


Hope this helps you.

Good Luck

Posted on Oct 06, 2009

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Posted on Jan 02, 2017

  • 3741 Answers

SOURCE: I have a 2002 Ford

P0442 code relating to the EVAP (Evaporative Emission System).a small emissions leak. also check the gas cap .Try cleaning the seals first and then try putting a little vaseline on the seals before getting a new gas cap. -------------
Code P0442-Evaporative emission control system. Canister Purge system failed the monitor test indicating a large leak (over 0.040”). Enabling conditions: Engine running after a 6 to 8 hour engine off period called a cold soak. The test runs when engine load is between 15 to 45% and inlet air temperature between 40 and 130°F. Blocking Action: This code can block the following monitors: Fuel Control, O2 monitor, Catalyst Monitor, misfire monitor. Testing: Check the purge hoses for leaks, leaking vapor management valve or loose gas cap.

This simply indicates that there was no flow from the evap system when the purge valve was energized. This could be cause of a few different reasons. First, check for leaks by visually looking at all evap lines for cranks rips or any tears. Basically, anywhere that fuel vapors can escape.
----------- Here is the test that will smoke the system for leaks with a smoke machine.

Evaporative Emission System Leak Test

SPECIAL TOOL(S)

CAUTION: The evaporative emission system must not be pressurized to more than 3.48 kPa (14 inches H2O)or damage to the evaporative emission system may occur.

  1. Connect the Evaporative Emission System Leak Tester to the evaporative emission test port.
  2. Close the canister vent solenoid.
  3. Pressurize the evaporative emission system to 3.48 kPa (14 inches H2O) .
  4. Monitor the system for two minutes . The system fails the leak test if the pressure falls below 2.0 kPa (8 inches H2O) .
  5. Repair any leaks as necessary.
  6. Repeat the leak test until the system remains above 2.0 kPa (8 inches H2O) after the two-minute test period.
---------- get it repaired ASAP because if you drive the car in same condition the emisson system can get damaged.and code will be p0445 ,now the code is p0442 its for leak in the emisson system. ---------------- This will help. Thanks please keep updated.please do rate the solution positively .thank you for using fixya.

Posted on Oct 15, 2009

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Article No.
03-20-3
10/13/03
DRIVEABILITY - MALFUNCTION INDICAOR LAMP
(MIL) ILLUMINATED WITH DTC'S P0442, P0455,
P0456, P0457, P1442 OR CHECK FUEL CAP LAMP
ILLUMINATED WITH DTC P0457
FORD: 1997-2000 CONTOUR 1997-2002 ESCORT 1997-2003 CROWN VICTORIA, MUSTANG, TAURUS 1998-2003 ESCORT ZX2 2000-2003 FOCUS 2002-2003 THUNDERBIRD1997 F-250 HD
1997-1999 F-250 LD
1997-2003 E SERIES, EXPEDITION, EXPLORER, F-150, RANGER, WINDSTAR
1999-2003 F SUPER DUTY
2000-2003 EXCURSION
2001-2003 ESCAPE, EXPLORER SPORT TRAC, EXPLORER SPORT
LINCOLN:
1997-1998 MARK VIII
1997-2002 CONTINENTAL
1997-2003 TOWN CAR
2000-2003 LS
1998-2003 NAVIGATOR
2002-2003 BLACKWOOD
MERCURY:
1997-1999 TRACER
1997-2000 MYSTIQUE
1997-2003 GRAND MARQUIS, SABLE
1999-2002 COUGAR
1997-2003 MOUNTAINEER
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ISSUE
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ACTION
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I have a 2002 Ford Taurus, and an engine sign showed up. However, I pulled out the code which is P0442. what is the problem, how much would that cost me and when do I need to fix it, can I wait for the...


P0442 code relating to the EVAP (Evaporative Emission System).a small emissions leak. also check the gas cap .Try cleaning the seals first and then try putting a little vaseline on the seals before getting a new gas cap. -------------
Code P0442-Evaporative emission control system. Canister Purge system failed the monitor test indicating a large leak (over 0.040”). Enabling conditions: Engine running after a 6 to 8 hour engine off period called a cold soak. The test runs when engine load is between 15 to 45% and inlet air temperature between 40 and 130°F. Blocking Action: This code can block the following monitors: Fuel Control, O2 monitor, Catalyst Monitor, misfire monitor. Testing: Check the purge hoses for leaks, leaking vapor management valve or loose gas cap.

This simply indicates that there was no flow from the evap system when the purge valve was energized. This could be cause of a few different reasons. First, check for leaks by visually looking at all evap lines for cranks rips or any tears. Basically, anywhere that fuel vapors can escape.
----------- Here is the test that will smoke the system for leaks with a smoke machine.

Evaporative Emission System Leak Test

SPECIAL TOOL(S)

CAUTION: The evaporative emission system must not be pressurized to more than 3.48 kPa (14 inches H2O)or damage to the evaporative emission system may occur.
  1. Connect the Evaporative Emission System Leak Tester to the evaporative emission test port.
  2. Close the canister vent solenoid.
  3. Pressurize the evaporative emission system to 3.48 kPa (14 inches H2O) .
  4. Monitor the system for two minutes . The system fails the leak test if the pressure falls below 2.0 kPa (8 inches H2O) .
  5. Repair any leaks as necessary.
  6. Repeat the leak test until the system remains above 2.0 kPa (8 inches H2O) after the two-minute test period.
---------- get it repaired ASAP because if you drive the car in same condition the emisson system can get damaged.and code will be p0445 ,now the code is p0442 its for leak in the emisson system. ---------------- This will help. Thanks please keep updated.please do rate the solution positively .thank you for using fixya.

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