How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask GM Tech (Cam) Your Own Question

GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 27644
Experience:  GM Grand Master Technician 2007. 11 years experience.
Type Your Chevy Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

Fault code P0496 check engine light on - vehicle runs fine

Resolved Question:

Fault code P0496 check engine light on - vehicle runs fine
Submitted: 3 years ago.
Category: Chevy
Expert:  Dino replied 3 years ago.

Hello welcome to the site I am Dino and will be able to assist you on this.

have you ran a evap test using the scan tool yet ?

have you used the evap smoker to see if their is a leak ?

Customer: replied 3 years ago.

Yes and yes. Originally, it read major emissions evap leak. Now it reads Purge Flow Fault.

 

Had 2 smoke tests done at GM dealership. they found no leaks and suggested new gas cap.

Expert:  Dino replied 3 years ago.

ok i have been looking to see if their is a service bulletin for this but it's all clear.

 

 

I'm going to reopen this and see if a gm tech has ran across this at the dealer.

Customer: replied 3 years ago.

It seems that many people who own GM's have run into a similar problem with check engine light staying on. Can't understand why GM hasn't figuired this out yet. As the vehicle runs fine, it wouldn't be much of a problem except when you need inspection...then it won't pass. After changing the battery, the light stayed off for 2 weeks and more than 600 miles.

 

This is nusence!

Expert:  GM Tech (Cam) replied 3 years ago.

Greetings and Welcome to Just answer.

Have you checked the purge solenoid on the top of the engine?

Customer: replied 3 years ago.
On the trailblazer there is a solenoid near the gas tank on the passenger side. It was replaced. If there is a purge solenoid on top of the engine, I am not aware of it. Do you know the exact location?
Expert:  GM Tech (Cam) replied 3 years ago.
Ok, confirm this is the straight 6 not the V6?
Customer: replied 3 years ago.
It's listed as 4.2 liter L6 Engine - Fuel Injection - Feedback Fuel System
Expert:  GM Tech (Cam) replied 3 years ago.

Ok, was there any dirt or dust in the vent solenoid when you changed it?

 

Customer: replied 3 years ago.
It was dusty but it's a sealed unit. The mechanic said it wasn't overly so. After it was changed, he cleared the code. The light came back on in a short period of time. The longest the light has been out has been when I changed the battery. Light was out for 2 weeks and 700 miles.
Expert:  GM Tech (Cam) replied 3 years ago.

Ok, If there is dirt plugging the purge line back to the engine, if the valve on the engine is plugged or if there is a wiring issue at the valve on the engine, this will be the result.

 

Customer: replied 3 years ago.
I appreciate the effort but the last time I was here, the mechanic said it was the Vent Selenoid or the gas cap. Neither corrected the problem. You don't sound real sure of the answer. Why would the light go out after replacing the battery and stay out for 2 weeks and 700 hundred miles? Is there a sensor in the vehicle that could be bad? Could it be electrical rather than mechanical?
Expert:  GM Tech (Cam) replied 3 years ago.

The light goes out because removing the battery resets these computers. The could be electrical and forgive me if I don't sound sure, I cannot put my hands on your vehicle to do the testing myself. There is a quick test. Find the purge valve on the drivers side of the engine.

Take the line off that goes to the tank. With the engine running, see if there is vacuum there. If so, take the electrical connector off and see if there is vacuum there. If so, replace that valve. If not then you have a wiring issue or the PCM.

I encourage you to try these and let me know. We can continue here and get this solved. And add as much detail as you can in your replies, that helps me out on this end.

 

Customer: replied 3 years ago.
So, you are saying that if I try these and they don't work, we can continue until we find a solution?
Expert:  GM Tech (Cam) replied 3 years ago.

Yes!!!!

 

Customer: replied 3 years ago.
Will I be able to ask for you directly?!
Expert:  GM Tech (Cam) replied 3 years ago.
Yes, on this issue, simply reply to this thread. If you want me to answer your next GM or GM product question, please put "For GMTECH Cam to Answer" and I should get it.
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 27644
Experience: GM Grand Master Technician 2007. 11 years experience.
GM Tech (Cam) and 8 other Chevy Specialists are ready to help you
Customer: replied 3 years ago.
Haven't had time to get it checked out yet. But have changed fuel neck, fuel pump, rear solenoid and gas cap. No luck yet..light still on but vehicle runs fine. Next step is to check front engine solenoid.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Last | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7497
    Have owned a repair shop for 25 yrs.
< Last | Next >
  • http://ww2.justanswer.com/uploads/TI/tim37857/2011-10-28_23053_S6301814.64x64.JPG Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7497
    Have owned a repair shop for 25 yrs.
  • http://ww2.justanswer.com/uploads/DT/dt69nova/2012-6-15_234154_pic1.64x64.jpg Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    6863
    ASE Master Certification. GM World Class Certification
  • http://ww2.justanswer.com/uploads/ggrote1/2009-06-27_031011_me.jpg Gary's Avatar

    Gary

    Chevy Technician

    Satisfied Customers:

    4944
    15 years GM master tech
  • http://ww2.justanswer.com/uploads/testedtuff/2009-09-26_170108_pictures.jpg John's Avatar

    John

    Master A.S.E Automotive technician

    Satisfied Customers:

    4071
    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • http://ww2.justanswer.com/uploads/RO/rodcuda/2011-7-25_224114_Donhoff1.64x64.JPG Neal's Avatar

    Neal

    Chevy Mechanic

    Satisfied Customers:

    2306
    Shop Owner and Mechanic on multiple makes.
  • http://ww2.justanswer.com/uploads/goodwrench9124/2008-11-09_220838_dscf0007.jpg goodwrench9124's Avatar

    goodwrench9124

    ASE Certified Technician

    Satisfied Customers:

    2041
    Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer, Hybrid certified
  • http://ww2.justanswer.com/uploads/DR/drivefast1971/2012-1-12_172422_0009051tQKh.64x64.jpg Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    1813
    18+yrs experience. State Inspector and Chevy Diagnostics