How do I repl the vent solenoid on my 2007 trailblazer 6 cyl. I believe it is located on charcoal canister

there are like 1billion cars noW doing this.

1. the gas cap was loose or bad !!!
2. theN the driver did not know it takes 30 driving cycles to clear the CEL lamp. OOPS 30? OBD2 DOES THAT. PER SERVICE MANUAL RULES, IF YOU READ THEM.
3. the fuse did not blow, or you'd have not asked where it is, I get that.!

99% of the time the cap was just loose or bad
my car the 1% time, the purge solenoid stuck
and my walmart silicon spray'd there (INSIDE IT) ended FAILURE for 50,000 more miles.
learn to buy AND USE a scan tool (borrow, rent ,buy)
tighten the cap again
scan the pCM see the cel lamp reasons./
push reset on the toll (CEL goes off if lucky and not 100 other DTC errors set)
and drive 3 times or more and the CEL stays off.

the other resets are(NO SCAN TOOL,. REALLY?)
1: PULL BATTERY LUG FOR 15MIN AND PUT BACK
OOPS RADIO GOES DEAD. dang
2: PULL ALL IOD FUSES. THE PCM MEMORY FUSE ONLY.
Ecm F29 IS IT(MEM) (PCM) 10AMPS
ALL DTCS NOW GONE, STORED. THE DATA FELL; INTO THE BIT BUCKET AS THEY SAY

IF ALL TESTS AND WILD GUESSING REPLACING ALL EVAP; VALVES. THEN COMES THE SMOKE MACHINE TESTS.
TO FIND THE LEAK
THIS IS AND EPA MANDATED MONITOR IN USA.
FOR SURE. THE 2 FUSES FOR BOTH EVAP VALVES ARE HERE.

This DTC checks for undesired intake vacuum flow to the EVAP system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system

Read more at: https://www.obd-codes.com/p0496
Copyright OBD-Codes.com
P0496 EVAP Flow During Non Purge Condition

DTC P0449: Evaporative Emission (EVAP) Vent Solenoid Control Circuit , your vent solenoid is opened or the wiring circuit is . The vent solenoid is by the charcoal canister at the gas tank .
P0449 Battery voltage is supplied to the EVAP canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver.

Vent solenoids there are 2 one on the intake manifold and one on top of the gas tank usually on top of the fuel pump module, the purge solenoid is located on or near the charcoal canister which is underneath the vehicle mounted by the gas tank

Hi there:
DTC P0496 - EVAP (evaporative emission) Flow During A Non-Purge Condition


The P0496 DTC code is a generic code which applies to all vehicle makes. A quick search on the 'net shows that this code seems to be more common with GM (Chevy, Pontiac, etc.) vehicles. In Acura, Honda, Hyundai, Kia, and Mazda vehicles, this code is described "EVAP system high purge flow" which is the same thing.

This DTC checks for undesired intake vacuum flow to the EVAP system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system

If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this code is set and the MIL (malfunction indicator lamp) is illuminated.

Symptoms of a P0496 DTC will include MIL illumination, and most likely no other noticeable symptoms. Some may experience a hard start / crank condition. In some cases the engine may run rich which may not detected, but can cause damage long-term (think: catalytic converter damage).

Potential causes of a P0496 EVAP code include:

• Faulty purge or vent solenod/valve
• Plugged EVAP canister
• Failed EVAP / fuel pressure sensor
• Poor electrical connection
• Short electrical circuit condition
(Hyundai, Isuzu)
• Faulty canister purge valve
• Blocked vapor canister
• Faulty vent solenoid
• Leaking EVAP system hose (Hyundai)
• Faulty purge flow sensor (Kia, Mazda)

Possible Solutions

The most common fix for this DTC is to replace the purge solenoid valve. However, be sure to do a proper diagnosis before replacing parts!

Ideally you would use an advanced scan tool, with the ignition on and engine off, you seal the EVAP system using the Seal/Purge function. Then, watch the fuel tank pressure sensor reading when you turn the purge off. If the pressure value is higher than the normal range set by the manufacturer, replace the EVAP canister purge solenoid valve. Refer to a model-specific repair guide for the proper specification.

If you don't have access to the scan tool, you could always disconnect the vacuum line at the purge valve going back to the charcoal canister. Unplug the electrical connector on the purge valve, start the engine, then put your finger on the valve where you disconnected the line. If you can feel vacuum there, the purge solenoid valve is faulty and needs to be replaced. Alternately, you could simply remove the purge solenoid valve and blow into it. It is normally closed, so if air goes through then you need to replace it.

If the purge valve checks out good, either the problem with the valve is intermittent or there is a problem with the fuel tank pressure sensor. To test the fuel tank pressure sensor you will need to have a high end scan tool to monitor the tank pressure with the gas cap removed. If the sensor shows vacuum with the gas cap removed, there is a problem with the fuel tank pressure sensor.

Here is a picture of one purge solenoid valve. Yours may look similar or different, consult a factory service guide or your local vehicle dealership for more details.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

I wouldn't replace the plugs, just yet. This sounds like the vent solenoid. They are usually around the fuel tank and sometimes located on the charcoal canister, Which I believe is where yours is. Test it with 12 volts it should click. if it doesn't then replace this. On newer cars like yours, when the vent or purge solenoids malfunction, they will pop an 02 code. If the solenoid clicks then check the wires right at the plug . they tend to break there. And the gasket your looking for is the intake manifold gasket. And looking for the solenoid, look under the emissions and EVAP systems.

There are several things that can make it necessary to replace the charcoal canister. It could be saturated with moisture (water). This can cause all kinds of problems with your evaporative emissions system including low or no flow of the fuel vapors to the manifold with the engine running and "purging"and high hydrocarbons escaping into the atmosphere when the engine is shut off because water saturation will prevent the hydrocarbon absorption that the canister is supposed to provide. This type of failure can be verified by removing the canister and either turning it upside-down andsee if any water runs out or (preferred method) measuring the weight of the canister. A saturated canister will weigh much more than a new one. Most manufacturers provide specifications for this.

A very common problem with charcoal canisters is that the charcoal bags inside the canister burst and the little charcoal pellets are released into the vapor lines. This can cause everything from clogging the vapor lines to jamming the vent solenoid or the purge solenoid. The pellets can even get drawn into the intake manifold and cause damage to valves or pistons.

Another common problem with charcoal canisters is that they can develop large cracks in the housing. The cracks are usually the result of water saturation that has frozen during cold weather. When the temperature rises and the water inside the canister thaws, there is now a large vacuum leak that can cause everything from Evaporative Emissions fault codes to "lean oxygen sensor" codes. This can also cause extreme amounts of dirt and debris to be ingested by the engine - particularly on vehicles with the canister in the rear. Dust and dirt gets stirred-up by the front wheels and wind draft and the rear gets blasted with it. The large vacuum leaks that can be created by cracks in the canister are like a magnet to this stuff and of course, get ingested by the engine.

Can it cause your Check Engine light to come on? ABSOLUTELY! The problems listed above can cause all kinds of engine control problems that will cause the light to come on. The most common codes would be "EVAP Vent Solenoid", "EVAP Purge Solenoid", "FTP Sensor", and "O2 Sensor Lean" codes. (There is no fault code for the canister itself, but canister failure can be the ROOT CAUSE of several codes)

P0106 is basically a leak somewhere in the intake manifold, could be vaccum hoses that are loose or cracking, or a bad MAP sensor which is very simple to change, about 30 seconds.

P0496- is an EVAP problem, could be as simple as a gas cap that is loose or not sealing properly. Turn the cap several clicks then clear the code out, see if this takes car of this problem. If not, look at your Canister Vent Valve, about $30, or the Canister Purge Solenoid, about $30 also.


I've personally had both these codes also, mine ended up being a bad MAP sensor. P0496 showed up when my significant other didn't put the gas cap on correctly or tight.

the p0496 means that the evap system flow during non-purge first check ur gas cap this can cause the check engine code if cap is good and on tight than the usual culprit is either evap purge solenoid and or canister vent solenoid sticking not expensive to replace by self in driveway but before u do check with a dealer in area and advise about code to see if covered should be since its an 08 evap should be covered [dont know mileage and or condition of truck which makes a difference on warranty ]

P0496 - Evaporative Emission (EVAP) System Flow During Non-Purge most likely the canister vent valve or purge solenoid is stuck open.