'04 AV P0496 Code

[zapit480v]

My "Check Engine" light came on.. I had the code checked at AutoZone.

P0496

Definition:
EVAP flow during a non-purge condition.

Explanation:
The ECM has detected pressure in the EVAP system, a non-purge condition

Possible Causes:
1) Purge or Vent Solenoid Failures
2) Plugged EVAP canister condition
3) Failed EVAP pressure sensor


Can anyone tell me where to find or have pics of the items listed in the "Possible Causes" portion and which item I should start with 1st, 2nd or 3rd? Or is there a way to test the solenoids or sensor and clean the EVAP canister.

A little history on the vehicle:
I purchased the AV on a reposession lot a week ago. The AV had sat on the lot for a year while I watched it waiting for the price to drop. There was no "Check Engine" light on when I purchased it. I imediately took it and had an oil change w/flush done. I had the tranny, transfer case and differentials flushed and filled. I drove it with no problems for 5 days. Since I got a new/used truck my wife made me take her Jeep in and get new tires on it for the winter. While she was driving it, my first mistake , is when the "Check Engine" light came on. She put gas in it and left the gas cap loose. I noticed it was loose when I topped it off to go up north for the holiday weekend after the "Check Engine" light had come on. I scanned through the owners manual and found a section that said a loose gas cap could cause the "Check Engine" light and should clear after a few starts. I drove the AV 150 miles up north and had several start-ups running errands while up north and then drove it 150 miles back home today. The "Check Engine" light is still on so I took it AutoZone when I got back home and the P0496 code and information listed above is what they gave me.

[MT-2500]

If gas cap was left lose or off with engine running.
Always clear code with a scanner and drive it and see if it comes back.

If it comes back I would suggest a engine capable scanner and get all codes.
The engine capable scanner has some test and data readings that will help find the problem.
The OBD11 scan at AZ may not be getting all codes.

For code repair flow charts and repair info on it you need a factory repair manual or a All Data online repair info sub.
http://www.alldata.com/products/diy/index.html
Let us know how it goes and what codes come back after code clear.

Good luck

[zapit480v]

Thanks MT-2500,

Is there a place I can take it to have the codes cleared rather than the stealer? Or is there a procedure for clearing the codes that I can do myself.. ie, remove + battery cable for 30 minutes?

EDIT:
I found this procedure on another site for resetting the OBD II, has anyone used it and found it to work?

The cheap, easy, free method

Simply disconnect your battery, turn on the headlights for about five to ten minutes, and re-connect the battery. This is pretty simple, but will likely result in you losing your radio presets and perhaps some other small things like that.

[MT-2500]

The battery disconnect is not safe and not a good way to clear codes and sometime does not clear codes.
The OBD11 system has a memory like a elephant.
Always use a scanner to clear code.
Some AZ stores and other parts places can read and clear code and is a free service.
Just do not buy the parts the will try to sell you until you check it out.
If problem was the gas cap was lose and you tighten it back up the code will clear itself after going threw the correct drive cycle.
But some times it take a while depending on driving.
Let us know how it goes.
Good luck

[MT-2500]

The battery disconnect is not safe and not a good way to clear codes and sometime does not clear codes.
The OBD11 system has a memory like a elephant.
Always use a scanner to clear code.
Some AZ stores and other parts places can read and clear code and is a free service.
Just do not buy the parts the will try to sell you until you check it out.
If problem was the gas cap was lose and you tighten it back up the code will clear itself after going threw the correct drive cycle.
But some times it take a while depending on driving.
Let us know how it goes.
Good luck

[zapit480v]

thanks again MT-2500,

I will take it this evening and have the codes cleared and post back after a few days of driving.

[zapit480v]

I had the codes reset.. I drove for 2 days and the MIL came on again. I took it back to AZ and had them check the code again, same code P0496. No other codes were present.

Below is a conversation about the same error code I have that I found on another website. I assume they are talking about one of the two following part #'s. Can anyone tell me which one, the names are similar and I can't tell which one they are actually talking about?

Vapor Canister Vent Solenoid (rear by the gas tank)- AC Delco #214-1078 or GM #10382105*.
Vapor Canister Purge Solenoid (at intake manifold) - AC Delco # 214-1105*, GM # 12582627.

****EDIT: I changed the part #'s based on the GM #'s the dealer gave me and cross-referenced them to AC Delco part #'s. I will pick-up a Purge Solenoid tomorrow and give that a try since the dealer mechanic said it is typically the one that goes bad. Althought the Vent solenoid also goes bad, just not as often. I will post back in a few days if this is the fix****



***********************************


Re: P0496
« Reply #7 on: 09/07/07 05:53 PM »
Quote from: homertd on 09/07/07 04:47 PM
P0496 is for undesired intake manifold vacuum to the evap system. possibly a bad purge solenoid valve.


Correct.... Evaporative Emission System High Purge Flow to be exact....

usually triggered by seeing flow during non-purge situations....

If the Evap purge valve does not seal properly, fuel vapors could enter the engine at an undesired timing causing drivability concerns. The control module tests for this by commanding the EVAP purge valve OFF closed and vent valve ON closed, sealing the system, and monitoring the FTP for an increase in vacuum. If the control module detects that Evap system vacuum increases above a calibrated value, DTC P0496 will be set.

[zapit480v]

Replacing the following part cured my trouble code:

Vapor Canister Purge Solenoid (at intake manifold) - AC Delco # 214-1105*, GM # 12582627.



But keep in mind the code can also be cause by:

Vapor Canister Vent Solenoid (rear by the gas tank)- AC Delco #214-1078 or GM #10382105*.


Hope this helps someone else in the future

[Mes103]

I am experiencing what seems to be the same problem with my '06. The only difference is that when I remove my gas cap it has pressure behind it and it takes about 15 minutes to put 10 gallons of gas in it. How can I tell if it is the Vapor Canister Vent Solenoid the Vapor Canister Purge Solenoid?

[MT-2500]

Welcome to AF
Same problem with a difference may be another problem.
The only way to tell is getting codes and doing some proper testing.
Best to start a New thread on your problem.
High jacking some one else problem is not good for finding the correct problem on yours.
Hit the New Thread button upper left of forum and give all information.
Codes and mileage and engine.
And someone will help you.

[ricebike]

doh, too bad the warranty was only good for 3 years/ 36,000 miles...

my brother has this same model, 2WD z66 model & is having the same code...and only 32,000 miles

i thought it was 1st w/ the locking gas cap from STANT & told him to replace it back to the OEM one, reset the ecu, then see if it comes back

===========

thank you for the update; i'll look into this as a possibility as well

[rabindra]

Hi zapit480v:
I am having same issue with my 2004 Chevy Avalanche. Mechanic asked $200 to change these two parts. I cannot afford. I have ordered the parts from rockauto for total under 50. I am going to try to do it myself. Appreciate if you could help me with step by step instructions since you have already done it. Do appreciate very much.

Do I need to reset the code for inspection OR does it go away after I change the parts since my inspection expires end of this month?

Vapor Canister Vent Solenoid (rear by the gas tank)- AC Delco #214-1078 or GM #10382105*.
Vapor Canister Purge Solenoid (at intake manifold) - AC Delco # 214-1105*, GM # 12582627.

Thanks,
Rabindra
rabindra@gmail.com

[gbnicholas]

I have an '06 silverado with the same code. Is the GM number listed in the above post the same numbers? What is the best way to clear the code without a scanner? Please advise. Thanks

[MT-2500]

Originally Posted by gbnicholas

I have an '06 silverado with the same code. Is the GM number listed in the above post the same numbers? What is the best way to clear the code without a scanner? Please advise. Thanks

Welcome to AF on your first post.

Your GM dealer parts man with your VIN no is the best place to check part no.

Streaching several years and modles on a several year old post and without what engine information is a very big streach.
So do not be surprized if parts are different.

As to clearing code only way is with a scanner.
The newer VCM/PCM have a memory like a elephant.
You can unplug them and unhook battery and spike them and take a hammer to them but the code will stay in there untill the scanner clears it.
And the code will come right back if the problem isstill there.

First step on your problem is clear code and drive and see if it comes present or history code and also recheck for any other codes.

If anything comes back start a new thread with your problem and give all information like engne make and model and mileage and any repair history and code no.
Then someone will help you.
Good Luck and.
Let us know how it goes.