2001 Chevy Blazer - Check Engine Soon Light

[Solittle]

We recently bought a used 2001 Chevy Blazer with the V6 engine for our daughter. After a few days she told me that the Check Engine Soon light had turned on in the instrument panel. I checked and the Low Fuel light was on also. I filled it up and took it to our mechanic who did not have time to work on it due to Christmas other than to turn the Check Engine Soon light off. The light stayed off until the gas gage went below 1/2 full and then came back on. This has happened twice since then - gas gage gets below 1/2 - light comes on - fill tank - reset light - light stays off untill the gas gets below 1/2.

The car operates normally in all respects.

I am planning on taking it to the mechanic to get it fixed but would like to pinpoint the problem rather than giving him a blank check.

Any ideas?

 

[DJ]

Re: 2001 Chevy Blazer - Check Engine Soon Light

Are you sure the gas cap is sealing?

 

[Navy Jr.]

Re: 2001 Chevy Blazer - Check Engine Soon Light

Another possibility is the coolant level. IIRC, this breed of vehicle uses Dex-Cool which has a reputation of eating intake manifold and head gaskets.

I would definitely look at the coolant. If it has turned muddy, therein may be the problem. If the coolant level drops below the 'Add' mark, air can get into the system. Dex-Cool and air are a very bad chemical combination.

Also, FWIW, GM touts that Dex-Cool can go 5 years or 150,000 miles without changing. (Some owners think that means 5 yrs/150k miles without checking!) I wouldn't wait that long to change it out. From what I've read, and there's lots to read on this subject, the current wisdom is to change it after 3 years or 36k miles.

Hopefully, everything is fine with your cooling system. But if it hasn't been checked for a while, it wouldn't hurt to look in the overflow tank and also inside the radiator neck.

 

[MikDee]

Re: 2001 Chevy Blazer - Check Engine Soon Light

I had the light when I first bought my used 96' S-10 pickup, our vehicle has the OBD11 computer controlled system, you need a code reader to check it, a bit harder to diagnose then the old OBD1 (using a paper clip between 2 terminals). Take it to Auto zone they will put a code checker on it for free, and tell you what code, & what it means. Mine was only an oxygen sensor, once I found out which one? despite the factory (right bank sensor 2) gobbledegook wording! It's been fine ever since. It could be as simple as a loose gas cap, it takes a few cycles for this to go away. By the way, I have the 4.3V6 it's a good basic engine, but has way too much technology (sensors) on it.

 

[Solittle]

Re: 2001 Chevy Blazer - Check Engine Soon Light

When I put the gas cap back on I turn it until it clicks. Is there a sensor that measures the pressure in the tank and could the sensor itself be the problem? Also if there is one where is it?

Navy - I will check the coolant but how does this relate to the Check Engine Soon light?

 

[SpinnerBait_Nut]

Re: 2001 Chevy Blazer - Check Engine Soon Light

When I put the gas cap back on I turn it until it clicks. Is there a sensor that measures the pressure in the tank and could the sensor itself be the problem? Also if there is one where is it?

Navy - I will check the coolant but how does this relate to the Check Engine Soon light?

Have you pulled the codes yet to see what it is throwing?
Go to your local parts house, most will pull them for free.

 

[Navy Jr.]

Re: 2001 Chevy Blazer - Check Engine Soon Light

Navy - I will check the coolant but how does this relate to the Check Engine Soon light?

If Dex-Cool gets muddy, it fouls the coolant sensors.

 

[Windykid]

Re: 2001 Chevy Blazer - Check Engine Soon Light

Sounds like the fuel cap is not venting and causing the fuel preasure to drop, hence an engine light. Take to auto zone when the light is on and get the codes.

 

[JCF350]

Re: 2001 Chevy Blazer - Check Engine Soon Light

More than likely a fuel evaporative system code. You can take to the auto parts place but it's going to take a mechanic to figure out where the leak or blockage is. Could be the gas cap or a number of other things. Just make sure they have a leak detector for the evap system and not just a regular smoke machine, the evap leak detectors use a much lower pressure than normal ones.