so ive had the service engine light come on periodically the last couple weeks. Its always gone off within a day of driving around so i havent thought much of it, cause it was usually within a day of filling the gas so id tighten the cap drive around and it goes off.

but today it came on after i turned the a/c on (havent filled up any gas since monday so its not this time). I was driving to work turned on the a/c it was pretty loud when it came on , and then the service engine light came on. After turning the a/c off the noise went away and then i thought about it i've rarely used the a/c this summer but thinking back to when ive turned it on that light has always followed.

is it possible problem with that causing it to come on, or just a coincidence? i've got to get the oil changed anyways so im going to bring it in and have the problem read.

 

Thats bizzarre.. Ive never heard of the air conditioner turning on the check engine light... I always thought the check engine light was basically for emissions and knock.. Y'know engine specific stuff. Maybe when it kicks on it bogs the engine to near stall. Perhaps a bearing is shot in the compressor? But I know very little about the engine light.

 

that could be a possibility actually. cause when i turned on the a/c i was at a stop light, and i did start to feel hesitations and the engine was dropping in and out like it wanted to stall, but that also stopped when i turned the a/c back off

 

Just because the check engine light comes does not always mean you have an engine related issue

I dont know what year your Monte is
but remember these cars have can have up to five computers in it.

The best thing to do, next time when the light comes on
Stop at AutoZone they will hook up the scanner free of charge.

I made a post a couple of months ago, that had GM trouble codes
If I find it again I will repost it
My computer carshed last week end and I lost almost everything but will be more then glad to dig up the info