03 Chevy Trailblazer "Service Engine Light"

[H Richard]

I've had this Trailblazer for 4 years, it has just 67,000 miles on it and it does everything I need. Great car, rides great, gets decent (21 mpg) mileage, is comfortable. A few months ago the "Service Engine Soon" light came on. I take to my mechanic and he can't find anything other than a slightly lose connection. Happens again a month later, but in the 5 days before I can get it in to my Mech. the light goes out. Happens again just before I am leaving on a trip our of state. Can't find anything wrong again reset's light. Light stays off across two states, then comes on in CO and stays on for three days then goes out again and stays off all the way home and for three more weeks. Then yesterday it comes on again. The Mechanic tells me it can be caused by over 300 different things, but none of them will cause any harm. It's a little maddening to see that light burning on the dash. I'm told you can't just disconnect the light (which was an old method of dealing with it) as it is an LED in the circuit.

Anyone have any idea for a fix?

 

[Muley Gil]

I have owned an/or driven several vehicles where the "Check engine" light has gone on.

The usual problem was a loose gas cap! The cure was to lossen the gas cap and then tighten it firming. Most times, this solves the problem and the light stays off.

Something to do with the emmissions system.

 

[H Richard]

That's the first thing I tried. Not the case, the "diagnostic checker" the Mech uses tells him it's in the EGR area, but can't find anything wrong.

 

[Vegetaman]

My '96 Pontiac has the check engine light on for months at a time for years now, and it's fine. Just an annoyance; it comes and goes. Especially in winter.

 

[steveno]

in my 2004 Colorado the service light has come and twice there was an evap valve(smog stuff) had to be replaced at $300 a pop. it came on a couple of weeks ago and the catalytic converter is bad and the dealer wants $920 for that. that isn't going to happen and just to turn the light out the dealer gets $70. I just wish it would go out after a period of time. it stayed out for a couple of weeks and came on again last week. there is an exhaust shop that will replace the converter for $300 so when I come with the money he will replace it. I have had 5 S-10 pickups with a total of almost 500,000 miles on them with out any converter problem. the Colorado has 135,000 miles on it now.

 

[beemerphile]

Go to AutoZone Advance etc. and they will read the code for free. Your mechanic should have added to his statement that there are over 300 things it could mean by telling you there is a way to find out which one it is. Not all of them are harmless. Some can foul out your cat converter. The light came on in my 2007 Silverado. The code checked P301 - cylinder 1 misfire. I put some silicone grease on the connector to the coil, cleared the code, and all is well. The key is to know the code number and what it means.

Further you said "Service Engine Soon" which is NOT a check engine, or MIL light. Normally that means that the mileage indicates that routine preventive maintenance is needed.

 

[cobra44]

This is common on GM models, I have seen it many times.
The one on my 03 Chevy is on all the time. Used really good equipment to check it, with no results as to the fault.
I just live with it. Many people put a piece or two of black electrical tape over it.

 

[Muley Gil]

"Many people put a piece or two of black electrical tape over it."

That's how the city garage used to "fix" the patrol cars.

 

[srgvaz]

I had the same thing happen to my chevy years back the trouble codes were from the O2 sensor it had four but we were able to determine it was the one right after the catalytic converter. After replacing it I noticed the tail pipe would shake the muffler shop wanted $360. for a catalytic converter & work I went home and called JEGGS ordered one for $85.00 & $10.00 shipping (fast shipping)went back to the shop a few days later $30.00 to install. All that fixed the dam light from having a mind of its own, and I kept the old converter and took it to a local guy who gave me $20.00 for it from what I understood he sends them to a company that removes gold or platinum from them and he gets like $50. for them. I bet since the price of those metals has gone up he's been making better money.
Your onboard computer stores trouble codes ever after the light goes out. In my experience Advanced AP has better service than AZone they should be able to give you an answer.

 

[pharmer]

As a pharma rep, I bought an '02 Impala. Check engine light came on at about 30K miles. When I gave it to my son in '05 it had 120K miles and the check engine light was still on. My '03 S-10 CEL came on @ 30K miles. Stayed on for about 8K miles. Now it's out. They are not called "idiot lights" for nothing. Around here, everyone offers "free inspection" for the CEL. Costs anyehere from $50 to $5K to make it go away. Ignore it. Joe

 

[clint_lnl]

auto zone will check it for free and post the code they give you and can tell ya the area the trouble is in or email me and I can get you the test from alldata to check the code out,, ALSO if the light is on its ok to drive just my not get the best MPG's .BUT if the check engine light is flashing its should not be driven. can cause damage to the cat converter

 

[jj2am44]

What engine?? What trouble code is stored?? If you live in a state with no emissions test, you are lucky. Here in Pa. if the light is on, you have to fix it before the machine will even let you try to run a test. This has to be run before you can get an inspection sticker.
On a lot of the older GM vehicles, the EGR ports under the valve can clog up with carbon. You can take the valve off and clean them.

 

[Lomax Anderson]

ignore it is advice I would not heed...too many things can cause it to light up ...some are tiny things but some can lead to expensive repairs...you need to find out what is causing the code ...then decide if you want to ignore it...but don't be surpised if you vechile decides to ignore you when you need to go somewhere important.

 

[klondike]

I agree with you that it is no fun to be far from home and have that stupid light nagging at you, never sure wether it is a minor problem or not.
It can spoil an otherwise great road trip.

 

[H Richard]

O.K. Went to shoot skeet about noon, and now the light is out. How long it will stay out is anybody's guess. Next time it comes on I'll take out to the mech. again and see if he can get to the bottom of it.

 

[bayfisher]

You don't need to wait for the light to come on again. The trouble code that caused your light to come on is now stored in the computer. Any reputable shop should be able to tell you what code it is, Even if they are just using a cheap code reader. I'm just a tech and I own 2 Snap-on scanners myself. If it does come back to an EGR code I generally remove the EGR(it's only 2 bolts on your model)then start the vehicle and try to rev it up, Like others have said, carbon builds up in the intake and this helps to blow it out. If it's the actual EGR itself, you have to replace it. They are no longer vacuum operated but are now electronic that have a motor to operate the pintle valve to control how much exhaust to recirculate. Good luck.