Wells EVAP Training with Sgt. Tech. P0440, P0441, P0442 etc.
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- เผยแพร่เมื่อ 27 ก.ค. 2024
- www.wellsve.com/ This video demonstrates how a typical EVAP system functions. P0440, P0441, P0442, P0456, P0457, P0455, P0443, P0446, P0449, P0450, P0451, P0452, P0453, P0496 trouble codes with explanations and possible causes. Why Wells fuel tank pressure sensors are rated the best.
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You choose to listen and then complain ? These videos are extremely helpful and very well presented and they are FREE. I say thanks a million times for these videos and the way they are done. God bless
Thank you Mark!
This has got to be the most thorough video on the EVAP system I have seen to date. I have been looking all over the internet for the last month trying to figure out why my codes keep coming back.
I now know much more than I ever knew before, thanks to this video.
I have copied down that list of 14 codes that I am sure will come in handy in the future.
I have replaced the vent solenoid on the canister, gas cap and just purchased the purge solenoid bolted to the air filter
Should get here next week.
2 Garages have yet to come up with what the root cause is. I even had them do a smoke test to check for leaks and they found none.
I am keeping my fingers crossed on the purge valve.
Codes are P0440, P0441, P0442, P0446.
2002 Toyota Sienna LE.
Barry
Thank you for the kind words. It sounds like you have a tough problem. Hang in there, there is always an answer. Below is the test procedure for the codes you have on your vehicle. The most probable causes are : cracked - loose hoses, canister, fuel cap, canister closed valve and vacuum switching valve ... in this order.
1. Verify the gas cap is a factory Toyota gas cap.
2. Locate the Canister Closed Valve (CCV), on or by the air filter housing, and verify the hose is connected and not loose.
3. Test the CCV, the Purge Solenoid (PS) and the Vacuum Switching Valve (VSV) on the charcoal canister, by manually grounding them and verify they operate and function properly. Some scan tools will activate the solenoids also, so it is a good thing to activate them through a scan tool so one knows the wire harness and the Engine Control Module (ECM) is OK. The CCV is normally open and it should close and hold vacuum when grounded. The VSV on the canister is normally closed, and when grounded, should open. The PS should open when grounded and apply vacuum to the charcoal canister for purge control and evaporative system testing.
4. Next, simulate an evaporative test and verify the system holds a vacuum and functions normally. To do that test, get to the ECM and backprobe the signal wire for the pressure sensor. It should read around 3.3 volts, no vacuum or pressure. Next, ground the CCV and the VSV on the canister. Start the vehicle, and if there is manifold vacuum to the PS, manually tap it to ground and draw a vacuum in the evaporative system and the fuel tank, then verify the pressure sensor voltage drops to around 2 volts. Then stop grounding the PS and see if the system leaks. If a smoke machine is used, the canister will leak, so clamp off the hose, that commonly has the Yellow stripe, to test the system.
5. Always ground the CCV and the VSV solenoid, on the canister, 20 to 30 times and verify they still operate when hot.
Stay in touch,
Mark Hicks
Wells Vehicle Electronics
Pipecorn i know you posted this 7yrs ago I but what was your final root cause? I’m chasing down this issue now myself on my 2011
3. On this system Toyota is using a leak detection module on the charcoal canister and the module includes a pressure sensor and a canister vent valve and a vacuum pump. The pressure sensor will monitor if the purge solenoid under the hood is working correctly and then monitor the system for a leak when the ECM grounds the canister vent valve and then the pump will pump vacuum into the system to check for leaks.
Wow. This makes more sense of other videos on evap system. I totally misunderstood the purpose of the vent valve before watching this video..Awesome job .
Thanks so much for posting this. This is the best explanation about the EVAP system that I have ever heard. It cleared up a lot of things for me.
Thank you for following up with the results. It was my pleasure.
Take Care,
Mark Hicks
You are very welcome. Knowing you enjoyed and learned from our production makes all the effort worth it!
Take Care,
Mark Hicks
Wells Vehicle Electronics
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.
Thanks for doing the impossible: making an evap emissions systems video entertaining. An evap video with 559K views(6/23/2019)proves it.
The voice-over actor must have been happy to use his acting skills.
Hahaha thanks for watching Joe!
Mike Becker, Senior Technical Instructor
When conventional educational tech videos are shown to a class of tired technicians it's easy for them to fall asleep. Not so with the Sgt .Tech video,it will keep them awake.
Haha glad it'll keep them awake.
Mike Becker, Senior Technical Instructor
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
@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
Thank you for the kind words. Your feelings about the video are exactly how we wanted it to come across.
The P0452 on your vehicle is many times caused by a broken Dark Green signal wire. Usually it breaks either by the master cylinder or under the drivers seat carpeting. Check the Dark Green wire for an open or short to ground from the sensor back to the Powertrain Control Module (PCM). Goes to Blue connector pin 39.
Hope this helps,
Mark Hicks
Wells Vehicle Electronics
Didn't know a EVAP video could be somewhat entertaining to watch. Now going to fix my P0442 issue. Thanx!
Haha who knew? Thanks for watching Jeff!
Mike Becker, Senior Instructor
Trying to work thru an EVAP issue on my truck . Wish I would have found this video first as it explains everything you need to know . One problem was the video was so entertaining it had me chuckling a bit due to the DI character's lines . Well done !
Thanks for watching!
~Ryan Wilsing
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.
wow thanks for the post. I have been doing this work for years and this is the best explanation of the way the system operates. Makes it a lot easier to troubleshoot when you know how it works and what it looks for to set the light.
You are welcome. If i can help you further, just let me know.
Mark Hicks
Wells Vehicle Electronics
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!!
You are absolutely correct! I have a Tech 2 and Snap on verus and they will both function the purge and vent solenoids on GMs. The verus is capable of doing this on most vehicles. Excellent input, Thank you,
Mark Hicks
Wells Vehicle Electronics
The purge solenoid is the gate to allow fumes stored in the canister to flow into the intake and then the combustion chamber. This typically happens when the engine is cruising and the vacuum is somewhere around 10 inches. If it was connected to the air intake it would pull much harder and the possibility of drawing raw fuel would be much greater.
Hope this helps,
Mark Hicks
Wells Vehicle Electronics
wow i remember watching an old school video (probably made in the 40/50s lol) on how the brake system works. set-up is like a "mechanic military training video." its black and white but very informative. i understand it more than reading my automotive books. this video is also similar to it. this is a great video for us all. thank you sir! i also had a P0452 DTC on my 2003 pontiac sunfire and i dont have any idea about the evap system. now i have a better understanding how to fix that DTC .
Thank you for the kind words. We are grateful you took the time to leave such a great comment.
Mark Hicks
Wells Vehicle Electronics
Yeah, I was leaning towards this as it is a common fix on my car. Thanks for replying back. If I figure it out I will post back with what it was and how I pinpointed it. Thanks again.
@carlosderek Thank you for the kind words. In fact we have another EVAP video coming out soon.
Mark Hicks
Wells Vehicle Electronics
Thank you for the kind words, they mean a lot to us!!
Mark Hicks
Wells Vehicle Electronics
You are correct andimillard. When the emissions testing station does a plug - in test, they are looking for monitors that are set or not. When you clear the codes the ready-ness monitors are also reset.
Mark Hicks
Wells Vehicle Electronics
Thank you for the kind words, they mean a lot to us!
We wanted a fun way to approach what can be a dull presentation. Kind of like taking medicine with a little bit of sugar.
Take Care,
Mark Hicks
Wells Vehicle Electronics
1. Activate the EVAP system vent and purge solenoids.
2. Check for the EVAP system to hold vacuum with either a gauge on the service port or by monitoring the Fuel Tank Pressure Sensor (FTPS) voltage.
3. Deactivate the EVAP purge solenoid, vacuum should hold and FTPS voltage should be higher than 1.5 volts.
The most common causes in order of probability for your vehicle are:
Fuel Cap
Vent solenoid
Purge solenoid
Evap system hose
Filler neck (rust hole)
Mark Hicks
Wells Vehicle Electronics
@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
Wowww... That was really a cool video and the learning really sticks with you! We as techs need more like this. Funny but gives real world learning that a tech can appreciate!!!! I subscribed!!! 🛠️🛠️🛠️🛠️🛠️👍
I wish they kept sgt. tech around , awesome..
@benjiego22 Thank you for the kind words. Glad you enjoyed the video.
Mark Hicks
Wells Vehicle Electronics
Thank you your kind words mean a lot to us!
Mark Hicks
Wells Vehicle Electronics
Excellent presentation. A great reinforcement for those recent seminars. And why do ppl complain about Srge Tech?
Hey, its old animations and stuff. The info is good, the presentation is....old. Thanks for watching!
Mike Becker, Technical Services Instructor
Great point! You are right if there is air by passing the MAF it will affect the fuel mixture and cause idle problems!
Thank you for your comment bujashaka it is right on!
Mark Hicks
Wells Vehicle Electronics
@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.
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
Markjhicks: thank you for your answer. as I mentionned, I changed the charcoal canister but this did not fix the problem for the code p0441. According to the video means that NO FLOW DURING PURGE CYCLE. So the problem is between the charcoal canister and the engine. I think there is only one part which is under the hood, is the VSV: Vaccum Switch Valve. You said you should check the VSV and Vent solenoid. I am gonna change the VSV then I will see if it will fix the problem.
Thanks again for your information.
We came to learn and share our experience in order to help each others.
Perfect! I love that!
Mark Hicks
Wells Vehicle Electronics
tanumi e hey! I know this is a 5 year old thread, and I haven’t been through all the comments yet but I am getting the same pO441 code on my 2001 B5 Audi. Did you figure out what the part was that was the curse of your p0441 code? I don’t open and just changing parts and crossing my fingers, luckily I am getting no adverse effects from this code other then the ‘check engine light’ with is annoying but not enuf too spend money I shouldn’t on EVAP parts!
Any reply would be appreciate! Especially after 5 years!!! 😀
God Bless
@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
@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
Thank you for the kind words! Now Carry on ...
Sgt. Tech
Wells Vehicle Electronics
Awesome info and explanation right there!! Thanks so much.
Hey Rosas, thanks for watching!
Mike Becker, Senior Technical Instructor
The canister purge solenoid and purge solenoid are the same part. Turn the key to "on" and check which of the two terminals are getting hot going to the purge solenoid. Then with the key still "on" ground and engine running, ground the other terminal and check for vacuum to the canister. If this does not occur replace the solenoid.
Mark Hicks
Wells Vehicle Electronics
Thank you for the update and great comment, we truly appreciate it!
Mark Hicks
Wells Vehicle Electronics
Very informative video. I don't mind your presentation style, it is much better than a computer generated voice like in some other videos out there.
Excellent, our goal was to have fun and teach in terms most everyone can understand.
Take Care
Mark Hicks
Wells Vehicle Electronics
Sometimes a good visual inspection can find a leak, but, you are right the only way to be sure is to have it smoked. If the problem is a sticky purge or vent solenoid they can be detected by activating the solenoid.
Mark Hicks
Wells Vehicle Electronics
A scan tool with the correct software will be needed to operate the leak detection pump and vent shut valve. Always verify the pressure sensor has a good 5 volts and a good ground and the signal wire read around 3.3 volts no vacuum or pressure in the system.
The leak detection module uses a 0.2 in orifice and pumps vacuum through the orifice and checks for the calibrated reading on the pressure sensor.
Well this is a good question. The best way is to use a smoke machine. The only other way is to do a very close visual inspection and try blowing through EVAP hoses, be careful not to inhale! The only other choice is to start guessing. i can help you with that. I will need the code to get started.
Mark Hicks
Wells Vehicle Electronics
Gracias! Excelente video explicativo muy claro para cualquier hispano parlante. ;Muy agradecido y like
Without knowing what vehicle you have, my first thought is a vent solenoid sticking issue. This is common on Domestic vehicles. On Asian vehicles it is also common for the vacuum switching valve to stick.
Mark Hicks
Wells Vehicle Electronics
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...
@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
@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
All I can do is advise the common failures. Most common is a leaking fuel cap, next is Canister vent solenoid. To be sure you will need to smoke the system, to find the leak. Best of luck if you have any further questions let me know.
Mark Hicks
Wells Vehicle Electronics
I am always here to help! We were all new at this at one time.
Please don't confuse what i said, EVAP canister purge solenoid, EVAP purge solenoid and the EVAP purge control solenoid are all the same part. Manufactures will at times call things different names but they are the same part. An EVAPorative will also have a vent solenoid. Usually these are the two EVAP solenoids the vehicle will have. The purge solenoid is on top of the engine and the vent solenoid is back by the tank usually.
There should be no gas leaking from the canister. This usually means the purge solenoid is stuck, the engine is badly flooded or running very rich. I am assuming you have a 5.3 engine. It is common for the fuel compensation sensor to cause this issue too.
Stay in touch,
Mark Hicks
Wells Vehicle Electronics
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.
At 1:09 I liked the choice of a WW2 Jeep to as an example of an older HC vapor emitting vehicle.
Usually the problem is associated with the purge solenoid.
Verify that the purge valve vacuum hoses are connected correctly (purge valve is near the ignition coils). If all looks good it is time to take a chance and replace the purge solenoid. To test it further you will need a scan tool and possibly a smoke machine.
Hope this helps,
Mark Hicks
Wells Vehicle Electronics
@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
@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.
@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
The most common cause by far for a P0442 on your vehicle is hoses leaking. Check the system hoses very carefully. The ones under the hood and by the canister are most suspect-able. A leaking fuel cap is also fairly common. Let me know wither way please,
Mark Hicks
Wells Vehicle Electronics
P0452 has to do with the fuel tank pressure sensor. It is not common on your vehicle. First check the connections to the PCM and the pressure sensor. Clean them with electronics cleaner.
Stay in touch,
Mark Hicks
Wells Vehicle Electronics
@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.
It was a miscue in the video, in this system the vent solenoid is normally open, you are correct.
@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.
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 ...
@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
@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.
@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.
Got a code P0441 on a 2016 Jeep Patriot. Well after replacing the gas cap twice, purge solenoid and NVLD it
was still throwing the same code. There is one other place it could leak vapors and the ECM will keep the solenoid
open to grab the fuel vapors instead of letting them leak into the atmosphere. There is a fuel vapor pressure
sensor. It lies between the gas tank and the charcoal canister. It may test good electrically so if it leaky, and mine
was, the ECM will open the purge solenoid. Thus getting 0% vapor registering and code P0441 will occur.
The device was indeed broken ,a small cap was loose and leaky. This was replaced and code was cleared. Fixed!
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.
Thank you for the kind words ... now get back to work private! :)
Mark Hicks
Wells Vehicle Electronics
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.
1. Locate the Canister Vent Shut (CVS) valve on the side of the charcoal canister, and the bypass solenoid under the cover next to the canister. Both solenoids have a Black/Yellow (BLK/YEL) wire that supplies voltage to the them.
2. Check to verify that there is voltage to the solenoids, key on. If there is voltage to both solenoids, the second wire is the wire the Engine Control Module (ECM) will ground to control the solenoid. On the CVS valve, backprobe the Green/White (GRN/WHT) wire, ground it and verify that the valve will close and hold vacuum. Also verify that it will open when the ground is taken away.
Follow Toyota TSB # EG041-07 for issues Toyota is having with the purge solenoid. There is an updated ECM for these codes.
If the ECM has been updated, then verify the purge solenoid under the hood operates correctly and supplies vacuum to the canister and shuts off when the solenoid is not being commanded by the ECM.
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
I have to agree, as long as it is not in an emission testing area. The fuel economy you will save will not justify the cost of the repair.
Mark Hicks
Wells Vehicle Electronics
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
1. Connect a Digital Volt Ohmmeter (DVOM) to the Orange wire at the Natural Vacuum Leak Detection (NVLD) assembly. Keep the NVLD connected.
2. Start the engine and voltage should be at least 10 volts.
3. Remove the vent hose from the NVLD assembly and check if vacuum is present from the port on the NVLD. If not, let the engine run longer until it starts purging and vacuum is felt on the port.
@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.
Then the ECM closes the vent valve and tests the fuel tank and gas cap and evaporative system for a leak. Always verify the vent line for this system is not restricted.
I hope this helps you. The most common fix is the updated ECM.
Mark Hicks
Wells Vehicle Electronics
This video was extremely helpful!! Thanks!
Thank you for the kind words, they mean a lot to us!
Mark Hicks
Wells Vehicle Electronics
Thank You Sgt! You're a lifesaver!
Thank you for the kind words. If you have any questions be sure to let us know.
Mark Hicks
Wells Vehicle Electronics
Hope this helps, if you ever have a question, please ask, I am more than happy to help all I can.
Mark Hicks
Wells Vehicle Electronics
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
I learned slot thanks this is the kind of videos nice presentation less talking more action
Thanks for watching!
Mike Becker, Senior Technical Instructor
@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
4. While watching the DVOM, plug the port and check if the voltage goes to 0 volts. The vacuum relief valve in the NVLD may make noise when doing this as it should release excessive vacuum.
5. If the voltage does not drop to 0 volts when the port is blocked, the NVLD assembly is bad.
A defective NVLD is by far the most probable cause.
Mark Hicks
Wells Vehicle Electronics
Hey thanks alot! And your videos are the best, I solved my problem with my 2000 chevy express Po452. It was a loose wire
You may have to clear the codes to get the light to go out. You will then have to reset all the monitors before you go for an emissions test. The canister is on the left hand front of the engine compartment under the PCM.
Mark Hicks
Wells Vehicle Electronics
Make sure the gas cap is tight, check for cracked vacuum hoses bythe canister and under the air cleaner.
Mark Hicks
Wells Vehicle Electronics
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
I would check with smoke wizard. You can find them on the AES wave site.
Mark Hicks
Wells Vehicle Electronics
P0446 TOYOTA - EVAP System Vent Control Circuit. great video by the way
It works and is wired on the principle of a strain gauge similar to a MAP sensor.
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
The vent solenoid is normally open. I think in this video we may have addressed it wrong. Apologizes. It is open to the canister where the fumes are held until the system purges. If the vent were closed the first symptom is trouble filling the tank. The air/fumes get trapped and turns the nozzle off. Hope this helps clear things a little better. Any other concerns let me know,
Mark Hicks
Wells Vehicle Electronics