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7 votes
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Canister purge valve constantly opening

The Purge is controlled by the PCM with a pulse width modulated switch signal. It is normal for it to cycle rapidly. This allows small amounts of the fuel vapor to be metered into the cylinders. This ...
Fred Wilson's user avatar
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3 votes
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Will the check engine light come back on if I erase the code using OBD2?

If the problem persists then yes it will come back on. Those type of fault codes are usually not instant tho so it may take some time to see it again. After fixing the gas cap the code may clear ...
narkeleptk's user avatar
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3 votes

Replace discontinued evap line?

Yup, you can replace it with generic hose.
Nick's user avatar
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3 votes
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Can I keep driving with P0456?

The code P0456 indicate a leak that is not so severe, compared to a P0455. Since you already replaced the fuel cap, so the problem can be in many other parts of the fuel system that can be very ...
Gabriel Diego's user avatar
3 votes

What are the side effects of disabling fuel tank ventilation?

Your view of the EVAP system is a little ascew. The EVAP system isn't open to the atmosphere. It doesn't "constantly" allow air to move into and out of the tank. The whole purpose of the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

95 blazer evap can purge solenoid valve to evap purge pressure switch valve

Don't know if this helps; best I could find...
SteveRacer's user avatar
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2 votes

Can't fill car up with gas

Slow or no flow for fuel in means no or low vapor flow out the vent system. Steps to test for testing for a blocked vent: Remove the CAN VENT fuse, #64 in the Underhood Bussed Electrical Center (...
Fred Wilson's user avatar
  • 11.6k
2 votes

Replaced my upstream O2 sensor, still get P1133 code

Check for an exhaust leak before or right after the o2 sensor, have someone use a rag and plug the exhaust while you listen. Or smoke test the exhaust system. Also check for vacuum leaks or any other ...
Ben's user avatar
  • 10.7k
2 votes

Difference between P0133 and P1133

The difference is regulatory not technical. P0133 is the SAE generic version. It satisfies the USEPA and CARB that this failure is covered under a code and conforms to regulated descriptive language. ...
Fred Wilson's user avatar
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2 votes
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Which codes does the front oxygen sensor throw?

From http://o2sensors.com.au/static/o2-sensor-identification-and-locations : So what is Sensor 1? Sensor 1 is the O2 sensor that is located before or upstream of the catalytic converter. (Pre-cat)...
Lynn Crumbling's user avatar
2 votes

How are EVAP system leaks detected by the ECU?

The most typical system used by GM is a vacuum decay type system. The system has 3 major components (for leak detection that is); purge solenoid, vent solenoid and a pressure sensor. Under normal ...
vini_i's user avatar
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2 votes
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1986 Dodge B250 - EVAP cannister removed, pressure in gas tank, ramifications / solutions

The tank should be vented, and done properly it should vent into a canister. The purge line to the carb is less important, but a hole in the carb under the butterflys is likely creating a vacuum leak....
SteveRacer's user avatar
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2 votes

I need the correct 2010 hyundai veracruz drive cycle steps to clear a "Permanent " P0456 code

I found this PDF with Drive Cycles for Hyundai's, which should include your Veracruz. Here are the relevant parts of the Drive Cycle to include the graphic from the PDF: General Instructions: Drive ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

Evap vent valve normally open - fuel vapors don’t leak out?

The canister is filled with activated charcoal, which is very effective at storing fuel vapors. Effective enough, in fact, that no fuel smell is detectable before the canister is purged by fresh air ...
WeakMech's user avatar
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2 votes
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Evap System Leak, Repair and Clear Codes to Pass USA State Emission Inspection?

I wanted to followup on this one, in case anybody else gets here. Brief review: In many (all?) states within the USA, an annual emission / SMOG test is required at the time of registration renewal. ...
zipzit's user avatar
  • 6,559
2 votes
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P171 Bank 1 running too lean - 2006 Mercury Milan

Since you have a scan tool, check the fuel trims to see if the ECM is adding fuel to compensate for a vacuum leak. ECM can add up to 25% more fuel, which would indicate a fairly large leak in the ...
user9181's user avatar
  • 1,392
2 votes
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Understanding the Voltage coming into an Evap Purge Solenoid

From what you are describing, it sounds like you are testing the voltage to the solenoid while the solenoid is unplugged. If so, that is not a valid test, you need to have a “load” connected to the ...
HandyHowie's user avatar
  • 25.4k
2 votes

Fuel/gasoline smell under car. Normal or problem?

You should not smell gasoline vapors. Usual causes are leaking fuel cap, leaking fuel tank, leaking fuel lines, leaking fuel filter, or issues with the evap system. The evap should vent itself into ...
jwh20's user avatar
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2 votes
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If I go in and remove car evaporator, does that mean I will no longer be getting any smell problems?

All parts of the ac circuit get dirty - which is why you need to clean them. Removing the evaporator will not remove all the smell and will stop the ac working. The ac can be used to demist the ...
Solar Mike's user avatar
  • 34.6k
2 votes

What are the side effects of disabling fuel tank ventilation?

In addition to the points raised in Paulster2's answer, disabling the EVAP system will give you a check engine light as soon as the EVAP monitor runs. From that moment forward, you will have a ...
MTA's user avatar
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1 vote
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05 Yukon XL Evap Test Incomplete, Need Troubleshooting Help

It appears GM vehicles are notoriously hard to get them to pass the EVAP portion of their internal smog tests. As laid out on this website, the procedure is quite arduous. I think one of the big ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
1 vote
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2005 Subaru Impreza WRX P1446 Fuel Tank Sensor Control Valve Circuit Low

"Circuit Low" immediately sounds like a voltage problem. I would begin by checking continuity with a multimeter from the sensor to your ecm (engine control module) and finding what voltages ...
1NAR's user avatar
  • 48
1 vote
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Evap code and the gas cap

You might try some rust converter like POR-15. If you do use something like that, you'll want to let it completely dry before putting the cap back on. This stuff will bond whatever touches against it ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
1 vote

Corolla EVAP Canister Location

From this page about a recall for these cars, it looks like it is mounted in the top of the fuel tank. There may be a panel under the carpet that you need to remove to get access -
HandyHowie's user avatar
  • 25.4k
1 vote

Are mineral oil smoke test machines sensor safe?

If you apply the smoke to the pipes and sensors for extended periods of time (weeks or months) then most likely yes. However, for a 1 off short period to find a fault probably not - this does assume ...
Solar Mike's user avatar
  • 34.6k
1 vote

Does every modern car have an evap vent valve?

Normally, pressure that develops during filling the gas tank is relieved by venting to the atmosphere via the filler tube (some locales require filler nozzles to be equipped with vapor recovery, in ...
Jimmy Fix-it's user avatar
1 vote

Why gas build up in tank?

TL DR: Most likely this is not an issue, but rather the EVAP system at work. Every emissions controlled vehicle has an EVAP system which controls the amount of fuel which is exhausted to the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
1 vote

How does EVAP interact with a vehicle?

First of all, it looks like my fuel tank has a separate "breather" hose separate from any kind of "EVAP" system. I can see it coming out from the bottom of the vehicle, and I'm guessing it probably ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
1 vote
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Vent Valve (Solenoid) leak and fuel consumption

Well there was a vacuum leak. Plain and simple logic dictates a drop in fuel efficient performance as the gases are not being recycled as the Evap system would when it's running without leaks at ...
Lawyer Aidroos's user avatar
1 vote

EVAP Leak One Day After Engine Work - Unrelated?

You can check the vacuum line for the purge valve and the related connector. If you follow the under hood vacuum diagram, it'll lead you to where the valve is. More than likely it's just a coincidence....
Ben's user avatar
  • 10.7k

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