2007 hhr P0496 and P0171
03-13-2012, 09:10 AM
#3
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Join Date: 06-30-2010
Location: Kannapolis NC
Posts: 25,739
Well let's see here....
P0171 Lean (check/clean MAF sensor).....Have you had the airbox off recently to change the filter? Or have you installed a K&N filter? An unplugged MAF sensor or an oiled filter will set that code for you.
P0496 EVAP Flow During a Non-Purge Condition.....First step on this on is to check your gas cap as the good Fireman above has pointed out, make sure its tight and that the o-ring is intact on the cap itself. This code is usually seen along with (P0442 & P0455 Evaporative Emission Control System Leak Detected (small leak) & Evaporative Emission Control System Leak Detected (no purge flow or large leak) - but not always).
Hope this helps, let us know what you find out if you can.
P0171 Lean (check/clean MAF sensor).....Have you had the airbox off recently to change the filter? Or have you installed a K&N filter? An unplugged MAF sensor or an oiled filter will set that code for you.
P0496 EVAP Flow During a Non-Purge Condition.....First step on this on is to check your gas cap as the good Fireman above has pointed out, make sure its tight and that the o-ring is intact on the cap itself. This code is usually seen along with (P0442 & P0455 Evaporative Emission Control System Leak Detected (small leak) & Evaporative Emission Control System Leak Detected (no purge flow or large leak) - but not always).
Hope this helps, let us know what you find out if you can.
06-18-2012, 01:54 PM
#4
Senior Member
Join Date: 02-06-2010
Location: Shreveport, LA
Posts: 580
P0496
I just got that code, and a week ago my DIC said to check the gas cap. The gas cap physically looks fine. I have been reading that this code is most frequently a problem with the purge valve/solenoid. I cleared the code with the machine at the auto parts store and will see if it comes back. Both Firestone and the local dealer want to do an $80 "smoke test" to see what is going on. Is this necessary or helpful? How much does this valve cost and how many hours of labor to replace it?
06-18-2012, 03:17 PM
#5
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Join Date: 06-30-2010
Location: Kannapolis NC
Posts: 25,739
Before completely clearing your gas cap of all blame, really check the sealing O-ring, they will become hard and brittle with age and that affects their sealing ability. I had a gas cap on my '07 (Paddy), that looked perfectly fine, but after going through the EVAP system and doing all the diagnostic checks, a new $11 gas cap cured everything.
Smoke tests can be helpful, but I've never heard of doing it on an HHR, you may wish to call your dealer's service manager for their take. Pressurizing the EVAP system with an opposite flow could damage something.
The purge solenoid (GM PN 25932567 - List Price $34.93) is not that hard to get to, and I can't imagine more than 1 to 1.5 hours of labor to replace it. But I'd start by investing in a new gas cap and seeing if it clears up the problem.
Smoke tests can be helpful, but I've never heard of doing it on an HHR, you may wish to call your dealer's service manager for their take. Pressurizing the EVAP system with an opposite flow could damage something.
The purge solenoid (GM PN 25932567 - List Price $34.93) is not that hard to get to, and I can't imagine more than 1 to 1.5 hours of labor to replace it. But I'd start by investing in a new gas cap and seeing if it clears up the problem.
06-18-2012, 03:33 PM
#6
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Join Date: 10-02-2005
Location: VA
Posts: 1,245
06-20-2012, 09:15 AM
#7
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Join Date: 11-05-2010
Location: Detroit, Michigan USA
Posts: 1,492
I just got that code, and a week ago my DIC said to check the gas cap. The gas cap physically looks fine. I have been reading that this code is most frequently a problem with the purge valve/solenoid. I cleared the code with the machine at the auto parts store and will see if it comes back. Both Firestone and the local dealer want to do an $80 "smoke test" to see what is going on. Is this necessary or helpful? How much does this valve cost and how many hours of labor to replace it?
How are things going with your HHR? Have you been able to contact the service manager as 843de had suggested about this?
Michelle, Chevrolet Customer Service
06-21-2012, 07:09 AM
#8
Senior Member
Join Date: 02-06-2010
Location: Shreveport, LA
Posts: 580
HHR update
I had a coupon for $30 off at Firestone so I took it in to them instead of the dealer. The dealer is further away, and the undiscounted diagnostic test price was the same either place. Unfortunately, I had followed the the auto parts store's suggestion and cleared the code. Firestone said that information had been stored in memory in addition to the code which would have been helpful in identify the problem. I don't know if they did a "smoke test" but they couldn't find anything wrong. I drove 500 miles yesterday and the CEL did not come on. The one thing different was that my gas tank was almost totally empty when the CEL came on. I had refilled before it got to Firestone and it hasn't been that close to empty since (I put 15.8 gallons in the tank that time). Could an almost-empty gas tank effect the test result that threw the code?
06-21-2012, 07:21 AM
#9
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Join Date: 06-30-2010
Location: Kannapolis NC
Posts: 25,739
Hmmm, well the only thing that I can think of, and its a long shot at best, is a possible over-pressurization of the EVAP system.
Maybe the nearly empty tank and toasty Texas temperatures combined to produce enough fuel vapor that it somehow overwhelmed the EVAP purge solenoid so it was venting to the atmosphere and the ECM recorded it as a "P0496 - Flow During A Non-Purge Condition".
So you might have an purge solenoid that's getting weak with age, or a one time occurrence due to a freak combination of conditions.
Maybe the nearly empty tank and toasty Texas temperatures combined to produce enough fuel vapor that it somehow overwhelmed the EVAP purge solenoid so it was venting to the atmosphere and the ECM recorded it as a "P0496 - Flow During A Non-Purge Condition".
So you might have an purge solenoid that's getting weak with age, or a one time occurrence due to a freak combination of conditions.
06-21-2012, 04:25 PM
#10
Senior Member
Join Date: 02-06-2010
Location: Shreveport, LA
Posts: 580
I was in Missouri
The CEL came on first thing in the morning, ambient temperature 75 degrees, in Springfield, MO. I still wonder if the previous message a week or so before from the DIC about a gas cap problem had anything to do with it.