Wells EVAP Training with Sgt. Tech. P0440, P0441, P0442 etc.

[007scarp]

Hi Mark,

I have a 2005 Honda CRV codes reading PO497,457 & 498. I checked the hoses and do not see any leaks. Makes a whistle sound when accelerating which sounds like a vacuum leak. Would you please advise on diagnostics. Thank you, Joe

[markjhicks]

@007scarp Hello Joe, This answer is going to take a couple responses, they only allow 500 characters.

1. This code indicates there is a large leak or low or no purge flow. On the 2004 Honda CR-V vehicle Honda has had some problems with the EVAP pressure sensor. Backprobe the Light Green wire at the EVAP pressure sensor with the fuel cap removed and no pressure or vacuum at the pressure sensor.

[markjhicks]

@markjhicks The voltage should be 2.46 - 2.56 volts. If the voltage is incorrect and the connection is good, then the fuel tank pressure sensor is faulty.

2. Verify the purge solenoid operates and if the scan tool shows purge operation the solenoid should be operating applying vacuum to the charcoal canister.

[markjhicks]

@markjhicks To test the purge solenoid, verify there is battery voltage at the Black/Yellow wire and when the Yellow/Blue wire is ground the purge solenoids should open and vacuum should be applied to the charcoal canister.

3. Next verify the canister closed valve closes tight and seals off the canister. The canister closed valve is located on the canister and when the White/Red wire is grounded the valve should close and the canister should hold vacuum.

[markjhicks]

@markjhicks If the canister closed valve does not close and hold vacuum, then it will need to be replaced.

4. Check all the EVAP lines and hoses for leaks and check for a cracked or leaking canister. Also verify the fuel cap is tight and not missing and the seal is good.

I hope this helps, if you have any further questions let me know!

Mark Hicks

Wells Vehicle Electronics

[GabeJH82]

@MarkjHicks thanks alot ima try that

[GabeJH82]

@MarkjHicks ok thanks alot I'm gonna try that

[GabeJH82]

I have a 2003 Dodge Ram 5.7L with code P0440 Evap Emission Control System Malfunction that im trying to fix. I replaced purge solenoid, check all hoses for cracks and tighten gas cap but couldnt solve it. You said the code is caused by not enough vacuum right? To fix this problem on my dodge what would I need to check and replace to solve this. any help or suggestings would be appreciated.

[markjhicks]

@GabeJH82Read this one first At the Natural Vacuum Leak Detection (NVLD) assembly, which is located at the front of the charcoal canister, which is near the front of the fuel tank, back probe the Orange wire with a voltmeter. Locate the vacuum line going to the canister and remove the line so a hand vacuum pump can be used to put vacuum on the line going towards the NVLD.

Read this one first

Mark Hicks

Wells Vehicle Electronics

[markjhicks]

@GabeJH82 The other line at the NVLD goes to the vent. Block the vent line.Using a hand vacuum pump, apply vacuum to the line while watching the voltage on the Violet/White wire. Voltage is supposed to change at approximately 1" Hg vacuum. Try testing this switch several times to see if the switch is sticking. Replace the NVLD if the switch is sticking. It is very common for the NVLD to fail on your vehicle.

I hope this helps you,

Mark Hicks

Wells Vehicle Electronics

[carlosderek]

man that explanation could not be any more clear. i really thank you i have a p0440 code, now i know what to look for. keep up the good work!!!!!!!!!!

[markjhicks]

@carlosderek Thank you for the kind words. In fact we have another EVAP video coming out soon.

Mark Hicks

Wells Vehicle Electronics

[4man321]

I have a 2007 Chevy Colorado with the 2.9 liter 4, I've had several shops attempting to isolate a po455 code. The gas cap has been replaced several times, the system has been smoked (two hours on smoke machine) no leak detected, i don't want to start throughing parts at it, however running out of options! Help!!!

[markjhicks]

@4man321 EVAP Leaks can be a real issue. We have a video coming soon I am sure you will be interested in. Let me ask you this: Does the fuel tank seem hard to fill at times?

Mark Hicks

Wells Vehicle Electronics

[4man321]

@markjhicks Yes mark at times it will stop filling and I know it's not full I'll have to start it again!

[markjhicks]

@4man321 This usually means the vent solenoid is sticking. Because it is not sticking all the time, it makes it very hard to find the leak. If you want to throw a dart at it, I would suggest trying the vent solenoid. If you want to test it. Try smoking it and energizing the solenoid with jumper leads and either a 9 or 12 volt battery. Do repetitive taps on the connector to try to get it to stick.

Mark Hicks

Wells Vehicle Electronics

[4man321]

@markjhicks Thank you very much for your suggestion I really do appriciate your help! ready to throw darts! this problem has been pleaging this truck since new, with all kind of excuses from dealer!

[4man321]

@markjhicks Thank you very much for your suggestion I really do appriciate your help! ready to throw darts! this problem has been pleaging this truck since new, with all kind of excuses from dealer! There are several things that GM just don't tell you! Mark are you aware that on about the fiveth setting of this code in the GM system it's also flagging the anti theft time out, which leaves you sitting for ten minutes!

[angelmenjivar91]

What if I get a code with a P0440 I don't have enough vacuum what can cause that?

[markjhicks]

@angelmenjivar91 If the engine can not generate enough vacuum, the computer will think you have an EVAP leak.

Mark Hicks

Wells Vehicle Electronics

[Colombianking497]

Can the egr be an issue that would cause the P0442 code to come up?

[markjhicks]

@Colombianking497 Normally not. What is the year, make, model and engine size of your vehicle with the P0442 code?

Mark Hicks

Wells vehicle Electronics

[benjiego22]

Well said.. very thorough

[markjhicks]

@benjiego22 Thank you for the kind words. Glad you enjoyed the video.

Mark Hicks

Wells Vehicle Electronics

[eallanboggs]

How far can you get on fumes. Not very far. My dad used to always say "Son, put some gas in that car. You can't get anywhere on fumes". Was he wrong? I don't thinks so but, the EPA seems to believe otherwise.

[markjhicks]

@eallanboggs I like the way you think! The next question should be, in my opinion, how much damage to the atmosphere do the fumes really cause? Or is this just another exaggeration?

Mark Hicks

[eallanboggs]

@markjhicks When I first started reading up on EVAP I used to think the charcaol canister turned the fumes into liquid gasoline since you can't run an engine on fumes, right? Boy was I in for a surprise. I found out the brain trust down at the EPA figured saw merit in fumes. I'm not surprised as they are the same people who gave us EGR which is another worthless engine mod. I guess I shouldn't complain since there is money to be made fixing EVAP and EGR. Keep up the bad work EPA!

[diz13oymik3]

95 and below don't need to run Obd test!! Save ur money n forget this video!!! U will still pass inspection!!

[KingOfTheClutch]

WTF?!?

[ghost27rsr]

ALL CARS UNTILL 96 HAVE BEEN RUNNING WITHOUT THIS OBD2 CODE .NOW VIDEO STATES THEY HAVE ADDED ANOTHER COMPONENT DUE TO ODB2 AND SO ON ,GIVING UP UR OLD CARS FOR CASH 4 CLUNKERS JUST GAVE THE GOVERMENT POWER TO PRINT MORE DOLLARS.I SAY KEEP UR OLD CARS AND KEEP UR DOLLARS IN UR POCKET!

[mrbadtech]

what a great video tool i am a master tech who has a son i coudnt convince not be a mechanic. he insist on doing this for a living [fool] he WILL! be looking at your videos awesome job!

[ghost27rsr]

BEING A MECH IS AWESOME BUT PEOPLE LIKE WHO TRADE UR OLD CARS 4 NEW ONES PUTS GUUD MECH OUT OF JOBS SO THE FOOL IS REALLY YOU AND UR BABYBOOMERS LOSERS!

[h8ncars]

Luckily everything has been under a manufacture extended emissions warrantee they have replaced the ECM , the charcoal canister the purge solenoid and some other stuff off of there guesses which funny enough that's what they told me they where doing because Honda support has removed the 97 del sol from there records lmao my car has 102xxx miles and the last visit they replaced a wire harness to the purge solenoid due to a loose connection with the two prong connected now I wait again for the li

[markjhicks]

@h8ncars If the new harness does not take care of it let me know.

Mark Hicks

[h8ncars]

Wish I seen this video earlier my 97 del sol was at the honda dealership for two months and has been back several times to this date for the p0441 light there comment was with a p0441 it could be anything grrrr.

[markjhicks]

@h8ncars Most common cause for the P0441 on your vehicle is a defective canister purge solenoid. here is the check: 1. At the canister purge solenoid check to see if there is battery voltage to the Yellow/Black wire any time the key is on. ground the Red wire and check to see if the solenoid passes vacuum through to the canister assembly.

2. Check the canister for being saturated.

Hope this helps, stay in touch,

Mark Hicks

Wells Vehicle Electronics

[AvgCorporateGuy]

This is just freakin' great. I do stuff like this all the time trying to get my 20 year old son and his friends to understand how cars work. And this was an excellent, informative, and enteraining way of explaining it. And taught me something too. I went out, did it, and sure enough, my 2003 Durango runs like a champ again at 104K miles. Even this old dog can learn a trick.

[markjhicks]

@AvgCorporateGuy Thank you for the great comment. It is people like that keep me doing this. Yea even an ole dog like me likes to get a pat on the head now and again.

Take Care,

Mark Hicks

Wells Vehicle Electronics

[DonMecanico]

haha! that video is funny and very good!!!!

[markjhicks]

@DonMecanico Best comment all week! It was a lot of fun to make too. Thanks for the kinds words!

Take care,

Mark Hicks

Wells Vehicle Electronics

[DonMecanico]

@markjhicks Well thanks for posting, this way is impossible not to learn, cheers!!

[markjhicks]

@DonMecanico Thank you for the kind words. Here is a challenge. If you think you know something, try to teach to everyone in a way all will understand. Thank you again, your comment really meant a lot to me.

Mark Hicks

Wells Vehicle Electronics

[doshubin]

Cool video!

I got a P0441 code on my 2002 Hyundai Elantra. The guy at autozone gave me a printout of possible issues for this code, for Kea though (apparently they did not have Hyundai on the list)

-Faulty purge control solenoid

-Faulty vent solenoid

-Blocked vapor

Where do I start troubleshooting? Is one of the above problems more likely to happen for this make and model then the other two? Don’t want just randomly start replacing parts. Any help would be GREATLY APPRECIATED. Thanks!

[markjhicks]

@doshubin It is common for the Canister purge solenoid / valve to cause this code on your Hyundai. I need you to e-mail me this question from my channel. there is not nearly enough room in the comments to give you testing and location instruction. If you would like them, please send me a message from my channel.

Mark Hicks

Wells vehicle Electronics

[bradyischamp]

great video

i have a scion tc and got two codes today

p0441 and p0455

i plan to replace the gas cap and hopefully will fix the engine light problem. i hope its not more complicated than this

[markjhicks]

@bradyischamp It could be the gas cap leaking. If it does turn out to be more than that let me know. Please also provide the year and engine size.

Mark Hicks

Wells Vehicle Electronics

[viperdaffy]

Informitive video

I have a 95 Nissan Maxima (Non California Emisson) and have a P0443 Mil code (Canister Purge Control Valve Circuit) but can not locate where it is. The Haynes manual doent show where it is either. Thanks for any help

[pete5668]

oorah! lol

[felipesegundo]

exelente video

[markjhicks]

@felipesegundo Thank you!

[1pigman]

thank you mark....

[1pigman]

i have a 2000 tahoe and a code of po452 pressure sensor/ switch low input. how do i fix it? thanks

[markjhicks]

@1pigman 1. Disconnect the Fuel Tank Pressure (FTP) sensor and check for 5 volts on the Gray wire and ground on the Black/White wire.

2. Jump the Gray wire to the Dark Green wire and see if the scanner shows 5 volts.

3. Check the Dark Green wire for an open or short to ground from the sensor back to the Powertrain Control Module (PCM). Goes to the Red connector pin 25.

If you just want to guess, replace the fuel tank pressure sensor and connector.

Mark Hicks

Wells Manufacturing L.P.

[Kasilindo]

ok i have a 2000 323i BMW with codes p0441 would this stop my car from starting??? I noticed some hesitation, soon after she died.

Tried to restart, several times until to no avail. Had her towed home.

Pulled the following codes: p0441

[markjhicks]

@Kasilindo

3. Functional test would be to supply power and ground to the valve, it should fully open and close when ground is removed. Would recommend testing multiple times in case it sticks intermittently and look for evidence of moisture that could cause it to hang up in cold weather.

4. Check the feed line to the purge valve, one should be able to draw freely through it and get the smell of fuel. Inspect the under side for damaged lines

[markjhicks]

@Kasilindo No, this code will not make the engine stop running. Check for spark and fuel first, let me know what you find and I will help you.

Testing code P0441 BMW

1. Access the purge valve, attached to the lower front part of the intake manifold, near the mass airflow sensor.

2. It has two wires going to it, the Red/White/Yellow wire has 12 volts key on, and the Brown wire is ground for the control circuit.

[sharkzf6]

Great video Mark! What happens when this sophisticated system fails to through a code when there is a leak? My 2007 Corvette smells of gasoline every time the tank level goes above 1/2 and yet no codes are thrown and after two visits my GM service manager says they can't find a leak even though he admits he can smell the gas! Thanks for any insight.

-JP

[markjhicks]

@sharkzf6 Thank you for the kind words. An EVAP monitor can happen only at specific times, this maybe the reason you are not getting any codes. Nonetheless, you need to have the canister, vent and purge solenoids checked. The solenoids are known to be intermittent. Stay with it, don't let it get out of warranty.

Mark

[vinman1029]

Mark,I put the charcoal can and vent valve on my sentra.Found it used on ebay.Did the trick.You saved me a ton of money.You're a genius.Thanks a million.

[markjhicks]

@vinman1029 Thank you for the reply. I am happy you have the problem solved. Genius huh...Well I always thought it was true, but now there two that do. LOL Always here to help the best I can.

Take Care,

Mark Hicks

Wells Manufacturing

[AutoTechHector]

Man i gotta tell you Mark, these are some of the best insructional and easy to understand automotive related videos. I'm gonna be taking the Engine Performance(A8) and HVAC (A7) ASEs in November, and these videos you have are helping me tremendously. . Really appreciate it!!

[markjhicks]

@AutoTechHector Well Hector I am not sure what to say, other than this is the best compliment you can give me. I hope you do well with the test, please stay in touch and let everyone know how well you do.

Mark Hicks

Wells Manufacturing L.P.



[javien108]

i have a 1997 malibu with a P0442 and idle is normal but sometimes well its at full operating temputer it has a very light jump its hardly noticable but the light it on

[markjhicks]

@javien108 A P0442 concerns a leak in the EVAP system which will typically have no drive-ability issues. The most common causes for this code on your vehicle are: fuel cap, filler neck, purge or vent solenoid and canister leaks. I suggest having the system smoked to help with the diagnostics.

Mark Hicks

Wells Manufacturing L.P.

[emilkvicktube]

Hi Mark, i havea 2001 malibu 3.1L and the code P0452 (evap pressure sensor low input) keeps coming back after resetting it. Do you have any wisdom for me, thanks Emil

[vinman1029]

Mark,I have a 2000 sentra with a 1441 code.It had a 455 and that was the gas cap.I pulled vacuum line off purge valve and I didn't fel anything at idle but did suck my finger when I revved it.Don't see any bad lines under hood or underneath.I took the black cover off in back and theres a bunch of hoses and three solenoids.I still smell gas when I get out of the car but it's not at the cap.Any input would be appreciated before going to the stealership.

[markjhicks]

@vinman1029 It is common to find a leak at the canister vent solenoid where it mounts to the charcoal canister. In this case it is usually best to replace the vent solenoid and the canister. Please let me know what happens,

Mark Hicks

Wells Manufacturing

[johntrebec]

I have a 93 ford escort. The evap hoses were rotting so I took them off and plan to buy new hoses. Can I drive the car ok without the evap system working? I know it's all about emissions but does it cause any abnormal wear on any other components when not operating?

[markjhicks]

@johntrebec Hello John, it will not be a problem driving your vehicle for a little while with the EVAP hoses disconnected.

Mark Hicks

[714caritas714]

does anybobdy know if my trouble code p0496 can fix by me or a mechanic i have a hundai accent 06

[markjhicks]

Check the EVAP purge solenoid on rear of intake plenum with vacuum gauge. You will find it has a small continuous suction even when not engaged. Chances are you will need to replace the solenoid.

Mark

[nobleheight]

On another subject, my cousin's father owns a 2005 Honda CRV. Sometimes while driving, the triangle of doom sometimes flashes on the dash (exclamation point inside a triangle.) I told my cousin that this is a warning light to indicate something is wrong with the traction control system. My cousin told me I was wrong and that the flashing triangle of doom indicates that the system is working properly. Please help me resolve this dispute with my cousin.

[markjhicks]

The triangle means there is a drivetrain problem. Go to the Wells website and the newsletter section. Go to Volume 11 issue 3 there is a real nice triangle of doom article there. Enjoy.

Mark

[nobleheight]

I am assuming that the rest position for the purge valve (meaning no electricity going to it) is closed. Is that correct?

[nobleheight]

I am assuming that the rest position (meaning no electricity going to it) for the vent valve is open. Is that correct?

[markjhicks]

It means the vent or purge solenoid is not grounded to activate.

[nobleheight]

The EVAP system has a warning label to warn against filling the EVAP system with more than 1 p.s.i for leak testing purposes.

However, it seems to me that on a hot day, more than 1 p.s.i is released from the gas tank when you remove the fuel cap to add gas. From this, it seems the EVAP system can really handle more than 1 p.s.i.

[markjhicks]

No more than 1 PSI vacuum not pressure.

[nobleheight]

Is there a way for a tech to test a fuel tank pressure sensor while the sensor is still installed on the vehicle?

[markjhicks]

Most scan tools allow running the EVAP monitor, the fuel tank pressure sensor can be tested at that time.

[nobleheight]

Wow! You mean you can kick off the EVAP monitor without driving the vehicle? I thought only Fords have that capability, because they have the On Demand KOEO/KOER Quick Tests.

Do other makes have this capability?

[markjhicks]

Yes

[nobleheight]

On this type of system, are both the purge and vent valves closed when the car is parked?

I assume the purge valve is closed. However, I assume the vent valve has to remain open to keep the tank from caving in during cooling of the tank.

Is my assumption correct?

[markjhicks]

Vent solenoid is normally open to ventilate during temperature changes and tank re-filling.

[nobleheight]

I've seen the threshold for leak detection listed as either 0.040 or 0.020 inches. Is that expressed as inches of mercury OR inches of water?

[nobleheight]

OBD II EVAP systems test for EVAP leaks, but what about OBD I EVAP systems?

If yes, then how many inches of mercury does OBD I use as the threshold for a leak?

[nobleheight]

How can you tell if the charcoal is bad?

[markjhicks]

Even if the charcoal is saturated with fuel it can be dried and reused.

Mark

[nobleheight]

How long does activated charcoal last?

How often should it be replaced?

If the charchoal is bad, will the ECM store a DTC?

[markjhicks]

The charcoal should last the lifetime of the vehicle. If the canister cracks internally or externally and the charcoal either falls on the ground or gets trapped in the system a code will set.

Mark

[nobleheight]

On this type of EVAP system, what would happen if you replaced the fuel tank pressure sensor with a simple resistor with a resistance value corresponding to a vacuum of 10 inches of water (the amount necessary to pass the gross leak test 4:34)? Would a constant and unvarying signal coming from the fuel tank pressure sensor cause the ECM to produce a DTC indicating something to the effect of a fuel tank pressure sensor circuit malfunction?

[markjhicks]

Yes it would set a DTC because it also looks for the value to drop when the vent solenoid is opened. Not quit that easy to fool the system.

Mark

[nobleheight]

Ok, but the DTC will probably be for insufficient flow at the vent valve rather than a malfunctioning fuel tank pressure sensor.

This brings up the topic that, at least theoretically, a malfunctioning fuel tank pressure sensor could cause the ECM to store a DTC for P0496 (insufficient flow), since I am assuming the ECM uses the signal from the fuel tank pressure sensor to make this determination.

[nobleheight]

Zero inches of water is the same as atmospheric pressure, correct?

[markjhicks]

that is correct

[nobleheight]

Why are we using the units "inches of water" here instead of "inches of mercury"?

When measuring intake vacuum or vacuum in an a/c system, the units inches of mercury is usually used.

[markjhicks]

Inches of water is a more precise when measuring very small amounts.

[nobleheight]

Does the fuel tank pressure sensor vary resistance, voltage, or current?

How many wires go to it? Is there a reference voltage wire going to it like a hall-effect sensor?

[markjhicks]

It works and is wired on the principle of a strain gauge similar to a MAP sensor.

[nobleheight]

Don't you mean the vent solenoid is normally open when the car is running? Wouldn't a constantly open purge solenoid cause a rich condition and rough idle?

[markjhicks]

It was a miscue in the video, in this system the vent solenoid is normally open, you are correct.

[nobleheight]

If the PCM commands the purge solenoid open, wouldn't it also need to command a decrease in fuel trim?

[nobleheight]

In a normally working EVAP system, should the pressure reading inside the gas tank be 14.7 psi (or atmospheric pressure)?

[markjhicks]

Not when the vacuum is pulling the fumes from the tank.

[nobleheight]

Is the HC in the canister in the gas state or the liquid state?

Do the fuel vapors in the canister condense back to liqud?

Is it ever good for the EVAP system to have liquid fuel in the canister?

[markjhicks]

It is in the gas state, it is a bad thing to have liquid fuel in the canister. No the vapors do not condense in the canister.

[nobleheight]

Do you have to drop the gas tank to access and replace the fuel tank pressure sensor?

[markjhicks]

Depends upon the vehicle.

[nobleheight]

I like the war analogy of competition between dealers and independent shops. Aftermarkets folks are the ALLIES while the dealer folks are the AXIS Nazis.

[DoggishBeast]

I have a 02 Jeep Wrangler 6.0 auto. The engine light is on and the rpms drop and rise when im in idle but fine when im in park or neutral. It also shifts late and revs up when it shifts gears.

[markjhicks]

1. Check for any vacuum leaks, even at the brake booster. This system will have an irratic idle if there is a vacuum leak.

2. Using a scan tool, check to see what the desired idle and what the actual is, normally these values are close to each other.

3. Block off the Idle Air Control (IAC) passage to see if that stabilizes the RPM.

4. Use a lab scope or Digital Volt meter to monitor the TPS voltage. If the voltage is erratic, check the sensor ground, if OK, replace the TPS.

Keep in Touch, Mark

[jayguy173]

i didnt hear you come agian

[DoggishBeast]

could this cause your jeep to stall or the rpms to drop?

[markjhicks]

Typically no, but on some rare occasions yes depending upon the type of vehicle.

What kind of problems are you having? What is the year, make, model and engine size? Is the check engine light "on"? Are there any codes stored in the computer?

I am happy to help you the best I can.

Mark

[11matayan]

hello my is chris and i have a 03 ford mustang cobra and i have a p0442 code and i don't know where to start and where to look please respond asap

[markjhicks]

Hello Chris,

A P0442 is not very common for your vehicle, however there are a couple failures you might want to check first before you have the system smoke tested. Check the fuel cap, some of the retail stores can do that for like AutoZone.

Then access the Canister Vent (CANV) solenoid on the carbon canister. Turn the key on and ground the Gray/Yellow (GY/Y) wire and check to verify that the solenoid is mechanically closed, by attempting to blow through it.

Next response...

[markjhicks]

If the solenoid is mechanically closing, inspect the lines and tubing of the Evaporative Emission Control System (EVAP) system, to verify that all connections are tight and that there are no cracked or broken lines or hoses.

I hope this helps...please keep me informed either way.

Mark

[dalukebark]

Dear Mark (or anyone with suggestions),

Ive got a 97 audi a4 1.8t with a p0441 evap emiss control sys incorrect purge flow. its not the gas cap, where you recommend i start looking??

[markjhicks]

Hello Dalukebark,

It is pretty common for the purge valve to stick open on your vehicle and cause a P0441 code to set. Remove the purge valve and first check to see if it is stuck open. If it is closed apply power and ground (9volt battery works well, polarity does not matter) to the valve and blow through it to see if it is opening all the way. You may need to do this several times. Either way it is probably your problem.

Keep in touch,

Mark

[Sirmau]

Hi Mark,

I have a 1999 Toyota Solara I have a code 0441... I know it is the purge solenoid.

The problem is, can't seem to locate the canister. Any help would be appreciated...

Thanks

[2006DURAMAX]

Hi Sirmau, the Canister is located underneath the car between the rear wheels, tuck in close to the body. It the black box above the rear subframe. mostly likely the VSV on that is bad but check all the hose and connections and crack othe canisters. The Solara shares the SXV-20 platform with the Camry.

Also, have you changed airfilter lately? There are VSV contections at the airbox and is it known to get disconnected when changing airfilters.

[Sirmau]

@2006DURAMAX

Thank you kindly for your support. This will help much vs taking the car to a tech.

I have not changed airfilters lately but will check for any disconnections.

[rickyorton]

Mark, my 99 Corolla has a P0446 code. I changed the VSV yesterday (the 1 behind the MAF sensor) now the code has come back. I believe it also relates 2 my problem when I pmup gas into the car. What do you think are the most common causes for this code? Thank You.

[markjhicks]

Rickyorton,

On a 99 Toyota Corolla it is very common for the Vacuum Switching Valve to have connection problems. I will assume at this point you do not have a scan tool that can read PIDS. If you do let me know and I will give you specific test instructions. Otherwise, test and verify that the purge solenoid and wire harness are all OK. The purge solenoid should apply vacuum to the charcoal canister when grounded.

[markjhicks]

Also verify that the hose from the purge solenoid to the charcoal canister does not leak. IF this all looks good and you are looking for the most common cause...it is time to replace the charcoal canister. Please keep me informed with the results.

Mark Hicks

[2006DURAMAX]

I had a P0446 on my 2001 Camry for months. I research and found that there's a VSV valve on the Charcoal Canister near the gas tank that is known to go bad. It is underneath the car and always in the open weather. I swap it out (just two hose and a connecter) with another one and the code finally turn off .

I also have a VSV on the intake but that one worked fine. I'm not sure if the Corolla is the same set up as the Camry. Just giving my 2 cents.

[Howardw007]

Any ideas on my '04 Monte Carlo SS with code P0455 ? I replaced the gas cap and purge solonoid with no luck so far.

[markjhicks]

The other most common causes for a P0455 on an 04 Monte Carlo is the vent solenoid and vacuum hoses. If you do not have a scan tool, you can test the vent solenoid integrity by activating it with a 9 volt battery and applying vacuum with a hand pump. It should hold vacuum when activated. This may have to be performed several times to find the intermittent problem. Hope this helps, please let me know the results of your testing.

Mark

[Howardw007]

Yes it turned out to be a faulty canister vent solonoid, thanks!

[markjhicks]

Thank you for following up with the results. It was my pleasure.

Take Care,

Mark Hicks

[atoxx1]

check fuel lines and hoses

[elgreco1223]

p0442 hyundai 2001 accent having trouble pumping gasi n car pump shuts off have to gas up very slow

[markjhicks]

Unfortunately, it is common on your vehicle for the charcoal canister to let go. Meaning the charcoal pellets are stuck everywhere in the system. Try disconnecting the vacuum hoses to the canister and look for the pellets. Also look at the fuel tank fill vent valve. It is on top of the tank but you can get to the hoses from the bottom. You will need to clean all the hoses, lines and check valves. Also replace the canister and possibly the diagnosis module for tank leakage (DMTL).

Mark

[KryzZTyaN]

I have 98 Isuzu Rodeo, the problem is that a few weeks ago the Check Engine will come on with code PO440 (EVAP). The problem is a leak in the EVAP system, you change the gas cap, tighten the hose to the EVAP system, but the light comes every time the gas tank is just a half, I have checked and all information indicates that there is faulty pump gasoline. But I'm not sure what to do.

[markjhicks]

I am going to assume you have the 6 cylinder engine. It is very common for either the vent or purge solenoid to be defective. It is also common for the o-ring on the fuel pump to leak. Here is a test you might find useful...please let me know if you have any further questions. I will post another reply with the test. Take Care...Mark

[mexicn22]

Hi, I have a 1997 honda accord with P0441

[markjhicks]

It is very common for the canister purge solenoid to be bad on your vehicle.

1. Locate the purge solenoid by the cruise control servo, verify that it is not stuck open. Also ground the solenoid, raise the engine RPM and verify that vacuum is applied to the charcoal canister. If the purge solenoid is faulty, replace the solenoid.

[markjhicks]

2. Check the purge flow switch on the firewall. Verify that the Black wire has a good ground and the Brown wire has approximately 5 volts with no purge flow and goes to ground when vacuum is applied to the purge flow switch when the purge system is operating while driving.

3. If the purge solenoid and purge flow switch test OK, check the vacuum "T" in the circuit. The vacuum "T" has orifices built inside it. If an incorrect part was installed, the purge flow code can set.

[markjhicks]

1. Test the system as outlined on TSB #02-02-S001. If no scan tool is available, will have to manually control the canister cut valve by grounding the Brown/White wire and then manually ground the purge solenoid by grounding the Red/Blue wire.

2. During testing, if the fuel tank pressure sensor does not indicate a vacuum, continue to ground the purge solenoid with the engine running and canister cut valve still closed.

[markjhicks]

Then listen for a vacuum leak noise around the top of the fuel tank.

Potential Causes:

Fuel Pump O-Ring — Fuel pump o-ring seal.

Please read the following test first.

[dippinsix4]

i have a 2003 mitsubishi gallant ES the code i have is p0441 andp0452 i cant figure it out i changed the fuel pressure sensor that sit on top of the fuel tank the code was cleared then 8 month later the same two codes are back again can anyone help?

[markjhicks]

dippinsix4,

it is common on your vehicle for either evaporative emission vent or purge solenoid to fail. The puge solenoid is located near the throttle body and the vent is near the fuel tank. It sounds like the failure is extremely intermittent, so it might be tough to pin it down. You can energize both solenoids with a 9 volt battery, jumping to the two pins on the solenoids. You might have to do this a number of times to find the one that is not clicking. I hope this helps ...

[emanuelrivera30]

Very nice explained,couldn't be better. THANKS ALOT....

[sonnetg2]

Thanks for sharing this. I had a P0440 code and it was such a pain to rid of. At the end, it was a faulty pressure sensor which i needed to replace.

[markjhicks]

A P0440 can be a tough diagnostics. If you seal the system and apply pressure or vacuum, depending upon the system, you can watch the voltage change on the pressure sensor. I am happy to hear you were able to correct your problem.