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Check Engine Light


rckowal1's Avatar
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09-26-02, 04:31 PM   #1  
rckowal1
Check Engine Light

What does it mean when the "Check Engine Light" comes on steady (not flashing)? Vehicle is a
'98 Pontiac Grand Am, 2.4L/4 cylinder engine, auto transmission, with 79000 miles. What can I
check myself before it has to go in to the shop for a computer diagnostic test?

The manual refers to this light as an "On Board Diagnostic - Second Generation" system. From
what I can tell, it seems to be mainly for emissions monitoring or control. The manual talks
about bad fuel, a wet ignition system &/or a loose fuel cap as possible causes for the light to
come on (steady). Addditionally, a flashing light indicates much more serious conditions requiring service.

It appears that this may be a pressurized fuel system. I've checked the fuel cap. The rubber seal
on it has some radial cracks which could result in a bad pressure seal. I'll try changing it as soon as I can.

Your assistance will be very much appreciated.

Best regards, Dick

 
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09-26-02, 05:40 PM   #2  
davidf
engine check lite

The light coming on means the computer has detected one of the many sensors giving an alarm to the computer which also can mean the sensor itself is defective and so will give a off normal reading reading to the computer even though the engine is really ok.The sensors monitor the emmisions system of the car and really is to alert you to not drive the car for the life of the car and put all that pollution into the air but it so happens that if the engine is defective in some way,the sensors will pick up an excessive emmisions condition and tell the computer and the computor will turn on the check engine light which is really an excessive emmisions light.

 
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09-26-02, 05:55 PM   #3  
rckowal1
Thanks Davidf for your reply.

If I understand you correctly, this light isn't indicating a serious engine problem but only that it may be emitting excessive emissions? I ask to better understand if this some thing that needs urgent attention, or some thing where servicing can be put off for awhile?

At the moment, I'm thinking that I can take it to Autozone & have them run a diagnostic code on it. This may give me a better idea of what to do next.

What do you think of this idea?

Best regards, Dick

 
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09-26-02, 06:00 PM   #4  
Joe_F
You have it right. Time to get it scanned to see what it is.

Find the cause of the light and rectify it. It could cause damage in the long haul.

 
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09-26-02, 06:45 PM   #5  
otter_
as well as having the codes

scanned, the fuel cap is the best place to start. Your car has a sealed fuel system. If pressure drop is detected in the system, the Check Engine light illuminates. The first thing we'll check for a cust. is if the fuel cap is loose, before going ahead and charging for running diagnostics.

 
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09-26-02, 11:05 PM   #6  
Run it to your local AutoZone, they'll run a scan for free. Let us know what they find and we can be a lot more help to you. Some of the items that cause your light can cause serious repair costs if not corrected.

 
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09-27-02, 06:04 AM   #7  
rckowal1
OK guys, I get the message. "Get the scan" to find out what's causing the light.

I'll report what I find out & we can go from there.

Best regards, Dick

 
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09-27-02, 04:08 PM   #8  
davidf
scan with a book

Buy a Haynes manual for your car and you can do the scanning yourself by watching the engine check lite blinks which are codes.Its in the Haynes manual and very easy and the book tells you what the codes mean pertaining to the sensors and troubleshooting guides will help you find the engine problem.

 
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09-27-02, 04:37 PM   #9  
rckowal1
Hi Davidf, Thanks again for your reply.

That's good to know. Although I don't have the Haynes manual, I have a listing of the codes
by numbers - if that's the way they blink out on the "check engine light". If you know - what's the procedure to get the light to blink the code? On some cars, it's a sequence of on-offs with the ignition switch.

By the way, a new gas cap has turned off the check engine light. We'll have to wait to be sure if it's for good.

Best regards, Dick

 
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09-27-02, 05:00 PM   #10  
otter_
OBDII

requires proper GM "Tech 2" scan tool or aftermarket equivalent to pull a code, as far as I understand.

 
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09-27-02, 05:34 PM   #11  
rckowal1
Hi Otter, Thanks for your reply.

OK, I sorta wondered whether a scan tool was needed. I think they're a couple hundred bucks. If so, think I'll just take it over to Autozone. You can't beat their price (free for check engine light test).

Best regards, Dick

 
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09-27-02, 07:24 PM   #12  
A flashing light means catalyst damaging concern.If its not flashing you have a code that still needs attention.Get the codes I will give you GM instuctions on diagnosing it.

 
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09-28-02, 06:12 AM   #13  
rckowal1
Hi Davo, Thanks for your offer to help & good information.

At the moment, there's nothing to diagnose since the "check engine light" went off after the gas cap was replaced. Obviously, it was a bad cap.

Should the problem return, I'll take you up on your offer.

Best regards, Dick

 
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