Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 12 of 12 Posts

·
Registered
2002 gmc envoy_slt
Joined
·
5 Posts
Discussion Starter · #1 ·
I have an '04 Envoy SLT. The check engine light recently came on and my husband suggested I check to make sure the gas cap was secured tightly. It was "stripped" and wouldn't tighten. He replaced the gas cap and the light has not shut off. I've checked the forums and have noticed that there are "codes" to indicate the reason the light is on - can someone tell me how I can find out if there is a code for the reason my light is on? Also, any suggestions would be appreciated. Thanks - there is also a wealth of info on this forum!
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
You got it. Welcome! There are code readers you can buy for $100-200, or you can pay a mechanic or go to a diagnostic center or a dealer.

Or you can go to most auto parts stores and ask them to read the code. They do this hoping you'll buy the parts there.

Write it down, Google for it. Come to trailvoy and run a search here for previous incidents involving that code.

If you don't see mention of it, then post a new thread with the code in the title and we'll help out.

Note that sometimes if you fix the problem that causes a SES light, it may take a day or three for the computer to become convinced you really fixed it, and to turn off the light. Many diagnostics have to pass three times for the vehicle to feel really secure that it's in the hands of an owner who understands it.

Are you folks DIY'ers or do you have a trusted mechanic?
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
you have to buy a code reader-- anywhere from $50 to $300 - depending how fancy you want it...
Or you can take it to autozone to have it read for free....

Under the steering wheel area--- there is a plug that you connect to-
with the scanner- it will show you a code. This code can tell you what the problem is.
There are hundreds of codes.

Its possible yours was due to the gas cap.
Give it a few cold engine start cycles for the light to clear.
The gas tank test is not run every time you start you car.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
as for the price discrepancy we quoted..
there are scanners you can buy that will simply read the code... bare bones. cheap little units.

then theres the fancy units that can erase the code and gather data and do all sorts of stuff...

then theres also software you can buy for your laptop-- which essentially turns your laptop into a scanner...

What youll be looking for is an OBD II scanner. OBDI if for older car.
 

·
Registered
2002 gmc envoy_slt
Joined
·
5 Posts
Discussion Starter · #5 ·
Thanks for all the info! I was hoping that once the gas cap was replaced the light would go off - but it has been over one week and no such luck! I will go to the local auto parts store and see if they can help with the code. Thanks again for the quick replies...I'll post an update!
 

·
Registered
2002 gmc envoy_slt
Joined
·
5 Posts
Discussion Starter · #6 ·
UPDATE: When I started my car this morning the check engine light did NOT stay on. I didn't want to get too excited - I just came back from lunch and the light did not stay on! Thanks again for all the advice. Have a safe and happy 4th!
 

·
Registered
2005 chevy trailblazer_ls
Joined
·
1,733 Posts
:tiphatAlso you don't want to put gas in while the motor is idling as this too may throw a code. Good to hear that your problem is solved,'only' a week for it to clear! I bet you were geting nervous ha,ha,oh well once again welcome to the site!:thumbsup:
 

·
Registered
2002 gmc envoy_sle
Joined
·
152 Posts
UPDATE: When I started my car this morning the check engine light did NOT stay on. I didn't want to get too excited - I just came back from lunch and the light did not stay on! Thanks again for all the advice. Have a safe and happy 4th!

Once the problem is fixed, some codes will clear themselves after about 50 miles. Sounds like your problem is solved.
 

·
Premium Member
2007 chevy trailblazer_ls
Joined
·
1,422 Posts
UPDATE: When I started my car this morning the check engine light did NOT stay on. I didn't want to get too excited - I just came back from lunch and the light did not stay on! Thanks again for all the advice. Have a safe and happy 4th!
It takes a certain amount of driving cycles for the pcm to see that there is not an issue and it will turn the cel off. And welcome by the way :tiphat
 

·
Registered
2003 gmc envoy_slt_xl
Joined
·
34 Posts
mine light came on as well when i let my wife drive it she got gas and forgot to put the cap on. when i drove it i was on the highway and it came on. when i stopped at my destination i chaecked and saw it was indeed the cap. so the next day i drove back into town (which was about 100 miles) and still see the light on. i went to autozone and they said that was what it was but they couldnt clear it. later that day it went out, but the next day it came back on. so what i'm asking is, is it safe to say that i need to replace the sensor. or do i try putting some seafoam and 93 octane gas in to see if it will burn hot enough to burn the carbon build up first? any input would be greatly appreciated.
 

·
Registered
2005 chevy trailblazer_ls
Joined
·
1,733 Posts
It will reset itself after a few cycles, but all you have to do is disconnect your negative battery cable for about 15 minutes and the computer will reset everything itself. I had the same thing happen, don't get too upset with your wife!:thumbsup:
 
1 - 12 of 12 Posts
Top