Question about 2002 Jeep Grand Cherokee

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I have the code P0455 and P0442. I replaced the gas cap with a new cap and had a mechanic look underneath to see if their were any hoses off or leaks and he couldn't find any problem. Could it be a valve problem in the rear by the tank? He cleared the codes and I drove it a couple of days and the check engine light came back on.

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Posted on Jan 02, 2017

  • 4 Answers

SOURCE: I have a engine code of P0455 and P0442. i bought

They always say gas cap, been my experience that it may be a cracked/collapsed hose. So take your time and inspect all your black hose that look about 1/4 to 3/8 in diameter in the engine compartment. Thats where I found my leak, crack rubber hose, the short rubber ones the connect to the rigid black tubes....
Hope this helps..

Posted on Jan 16, 2010

Testimonial: "thank you"

  • 1608 Answers

SOURCE: 2002 wrangler 4.0 6 cylinder

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Here is a picture of the canister and all the other parts.Let me know if this worked for you.One other thing is if you have a leak taping it will not keep it from leaking.You will have to replace the part that is leaking or not working properly.Let me know how this picture works out.This is the first time I have tried this.Good luck and thanks for using fixya.

Posted on Nov 13, 2010

Dak408
  • 277 Answers

SOURCE: 2002 jeep wrangler 6 cylinder:

THE P0455 CODE POSSIBLE CAUSES ARE

  • Leak at Gas Cap
  • Vehicle History and Service Bulletin Investigation
  • Visual and Physical Inspection
  • Verify Evaporative Emission Leak
  • EVAP Purge Solenoid Operation
  • Intermittent LDP Monitor Failure
  • Evaporative Emission Leak Detection
  • Gas Cap
  • LDP Component Leak
WHAT ENGINE DIAGRAMS I HAVE IS BELOW WITH DEFINITIONS
  • dak408_24.gif
On 4.0L 6 cylinder engines, a molded vacuum tube connects manifold vacuum to top of cylinder head (valve) cover at dash panel end. The vacuum fitting contains a fixed orifice of a calibrated size. It meters the amount of crankcase vapors drawn out of the engine.

On 2.5L 4 cylinder engines, a fitting on drivers side of cylinder head (valve) cover contains the metered orifice. It is connected to manifold vacuum.

A fresh air supply hose from the air cleaner is connected to front of cylinder head cover on 4.0L engines. It is connected to rear of cover on 2.5L engines.

When the engine is operating, fresh air enters the engine and mixes with crankcase vapors. Manifold vacuum draws the vapor/air mixture through the fixed orifice and into the intake manifold. The vapors are then consumed during combustion.

EVAP/PURGE SOLENOID
The duty cycle EVAP canister purge solenoid (DCP) regulates the rate of vapor flow from the EVAP canister to the intake manifold. The Powertrain Control Module (PCM) operates the solenoid.

During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid. When de-energized, no vapors are purged. The PCM de-energizes the solenoid during open loop operation.

The engine enters closed loop operation after it reaches a specified temperature and the time delay ends. During closed loop operation, the PCM cycles (energizes and de-energizes) the solenoid 5 or 10 times per second, depending upon operating conditions. The PCM varies the vapor flow rate by changing solenoid pulse width. Pulse width is the amount of time that the solenoid is energized. The PCM adjusts solenoid pulse width based on engine operating condition.

FUEL FILLER CAP
The plastic fuel tank filler tube cap is threaded onto the end of the fuel fill tube Certain models are equipped with a 1/4 turn cap.

The loss of any fuel or vapor out of fuel filler tube is prevented by the use of a pressure-vacuum fuel fill cap. Relief valves inside the cap will release fuel tank pressure at predetermined pressures. Fuel tank vacuum will also be released at predetermined values. This cap must be replaced by a similar unit if replacement is necessary This is in order for the system to remain effective.

CAUTION: Remove fill cap before servicing any fuel system component to relieve tank pressure. If equipped with a California emissions package and a Leak Detection Pump (LDP) , the cap must be tightened securely. If cap is left loose, a Diagnostic Trouble Code (DTC) may be set.

LEAK DETECTION PUMP
The Leak Detection Pump (LDP) is used only with certain emission packages

The LDP is a device used to detect a leak in the evaporative system.

The pump contains a 3 port solenoid, a pump that contains a switch, a spring loaded canister vent valve seal, 2 check valves and a spring/diaphragm.

Immediately after a cold start, engine temperature between 40 °F and 86 °F , the 3 port solenoid is briefly energized. This initializes the pump by drawing air into the pump cavity and also closes the vent seal. During non-test test conditions, the vent seal is held open by the pump diaphragm assembly which pushes it open at the full travel position. The vent seal will remain closed while the pump is cycling. This is due to the operation of the 3 port solenoid which prevents the diaphragm assembly from reaching full travel. After the brief initialization period, the solenoid is de-energized, allowing atmospheric pressure to enter the pump cavity. This permits the spring to drive the diaphragm which forces air out of the pump cavity and into the vent system. When the solenoid is energized and de-energized, the cycle is repeated creating flow in typical diaphragm pump fashion. The pump is controlled in 2 modes:

Pump Mode: The pump is cycled at a fixed rate to achieve a rapid pressure build in order to shorten the overall test time.

Test Mode: The Solenoid Is Energized With A Fixed Duration Pulse. Subsequent fixed pulses occur when the diaphragm reaches the switch closure point.

The spring in the pump is set so that the system will achieve an equalized pressure of about 7.5 inches of water.

When the pump starts, the cycle rate is quite high. As the system becomes pressurized pump rate drops. If there is no leak the pump will quit. If there is a leak, the test is terminated at the end of the test mode.

If there is no leak, the purge monitor is run. If the cycle rate increases due to the flow through the purge system, the test is passed and the diagnostic is complete.

The canister vent valve will unseal the system after completion of the test sequence as the pump diaphragm assembly moves to the full travel position.

VACUUM LINES
A vacuum schematic for emission related items can be found on the VECI label. Refer to Vehicle Emission Control Information (VECI) Label for label location

dak408_25.gif
VAPOR CANISTER
The evaporative (EVAP) canister is located in the engine compartment on the left inner fender.

A maintenance free, EVAP canister is used on all vehicles. The EVAP canister is filled with granules of an activated carbon mixture. Fuel vapors entering the EVAP canister are absorbed by the charcoal granules.

Fuel tank pressure vents into the EVAP canister. Fuel vapors are temporarily held in the canister until they can be drawn into the intake manifold. The duty cycle EVAP canister purge solenoid allows the EVAP canister to be purged at predetermined times and at certain engine operating conditions.

ONE WAY TO CLEAR ENGINE CODES WITH OUT HAVING A DIAGNOSTIC COMPUTER IS UN PLUG THE BATTERY AND LEAVE IT SIT FOR ROUGHLY 20 MINUTE AND REHOOK UP THIS MIGHT CLEAR THE CODES WITH OUT A COMPUTER.. BUT IF THE PROBLEM ISN'T FIXED THE CODES WILL SHOW AGAIN..


HOPE THIS HELPS

Posted on Nov 14, 2010

  • 3640 Answers

SOURCE: p0455 and p0442

p0455-- emission control system ( a large leak ) the most common cause is a bad seal on fuel cap, remove and replace cap, if light stats on. replace cap. if not the cap it could be any where in emission system. p0442 is--same as above. Code p0442 indicates a fuel vapor leak in the EVAP control system. To fix this problem, remove and reinstall the gas cap. Clear the codes and drive to see if the codes reappear. If the code appears again replace the gas cap or inspect the system for cuts or holes in the tube or hose. good-day !

Posted on Aug 24, 2011

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Code p0442 and p0455. When I start the truck it takes about 5 seconds to actually start. If I turn it off and start it again, it starts right up.


Well code 442 is a small EVAP leak and 455 is a large leak. Those codes could be a faulty gas cap or any leak in the gas tank venting system including the gasket around the fuel pump. The engine computer pressurizes the gas tank when the engine is running to check for leaks.
The starting issue could be a faulty check valve in the fuel pump allowing fuel pressure to drain back into the gas tank.

Jan 30, 2014 | Dodge Cars & Trucks

2 Answers

2005 Hyundai Elantra P0442 code?


The code means the computer has tried to vent the gas tank and has found a small leak in the vent system.
You may need to research the code to get the testing procedure for your model and year.

Oct 05, 2012 | 2005 Hyundai Elantra

2 Answers

Code po455 2004 chrysler sebring 2.4l sohc G vin code


The code is for a large leak in the fuel tank or evap system.

Some possible cause are - a leaking fuel tank, gas cap, hoses to and from the vapor canister and engine, and a faulty canister.
It's possible a valve is stuck open and allowing the engine to pull fumes in when the system is supposed to be closed, but if this were the case the computer should also set a code for that valve.

Here is the definition.

P0455 CHRYSLER Description The Evaporative emissions (EVAP) system is design to prevent the escape of fuel vapors from the fuel system. Leaks in the system, ca allow vapors to escape into the atmosphere. The leak detection system tests for EVAP system leaks and blockage.


During the self-diagnostics, the Powertrain Control Module (PCM) first checks the Leak Detection Pump (LDP) for electrical and mechanical faults. If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.
Read more: http://engine-codes.com/p0455_chrysler.html#ixzz24EH3F11s

Aug 21, 2012 | Chrysler Sebring Cars & Trucks

2 Answers

P0455 and p0442


p0455-- emission control system ( a large leak ) the most common cause is a bad seal on fuel cap, remove and replace cap, if light stats on. replace cap. if not the cap it could be any where in emission system. p0442 is--same as above. Code p0442 indicates a fuel vapor leak in the EVAP control system. To fix this problem, remove and reinstall the gas cap. Clear the codes and drive to see if the codes reappear. If the code appears again replace the gas cap or inspect the system for cuts or holes in the tube or hose. good-day !

Aug 24, 2011 | 2002 Jeep Grand Cherokee

2 Answers

P0449 and P0455 error code 2008 2wd gmc envoy 30,203 miles


P0449 - Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

P0455 - Evaporative Emission Control System Leak Detected (no purge flow or large leak)

Both are refer at EVAP system; other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456

This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. 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: 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)
Other leak or damaged piece in EVAP system

Possible Solutions: 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, and/or
Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary


Hope helps.

Apr 23, 2011 | 2008 GMC Envoy

1 Answer

2007 saturn aura, engine service code P0442, with a new gas cap, what else could it be?


2carpros has this to say about Po442
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

Mar 06, 2011 | 2007 Saturn Aura XR Sedan

1 Answer

I have a engine code of P0455 and P0442. i bought a new gas cap and the light was reset and now it is back on. What should I do next? and should i take my car to the dealership for diagnostics.


They always say gas cap, been my experience that it may be a cracked/collapsed hose. So take your time and inspect all your black hose that look about 1/4 to 3/8 in diameter in the engine compartment. Thats where I found my leak, crack rubber hose, the short rubber ones the connect to the rigid black tubes....
Hope this helps..

Jan 13, 2010 | 2002 Jeep Liberty

1 Answer

2003 Jeep Liberty


p0455 is evap control system no purge or large leak
p0442 is evap control system leak detected (small leak)

the cause for both could actually be a loose gas cap.

Dec 18, 2009 | 2002 Jeep Grand Cherokee

1 Answer

Error codes p0442 & P0455


Those are both Evaporative Emission Control System related.
442 is a small leak has been detected.
455 is a bigger leak has been detected.
Check all your connections, (electrical & vacuum lines) as well as check for any cracked, loose vacuum hoses in the system, as well as clean "O" ring on your gas cap well and threads in filler pipe & make sure gas cap is tight. Do the gas cap first & see if codes dissappear, but it may take a new gas cap. These codes commonly appear shortly after getting gas, due to cap not back on tight.

Oct 02, 2009 | 2001 Dodge Caravan

1 Answer

Code P0456,P0455, &P0442


hello po442 ,po455,po456 is leak detected possible, check the gas cap , basicaly you have a leak that is larger than 0.020' and smaller than 0.040' in the gas evaporative system use your nose to find this one thanks

Feb 14, 2009 | 2003 Dodge Durango

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