I was wondering what procedure is followed when "service engine soon" light is on. It's a 89 C4 base coupe. I recently (within 1000 miles) had the oil, coolant and all other fluids changed or filled. All levels are fine and car runs great. The Light comes on after driving a while. When I shut the engine off, of course the light goes off as well. The next time I start the car, after about 10 miles of driving the "service engine light comes on again.
Does it just need to be reset? If so, How?
Thanks... Joe

 

You need to retrieve the code. Something is wrong with the car and the ECM is reporting it to you.

The code will still be stored in memory even when its off, until you reset it.

The way to check the code is to take a paper clip, go under your dash to the ALDL connector, should be at the bottom right of the dash. Touch the paper clip to the two far top right terminals. On the top row, the last two. These are the A and B terminals.

Make sure the ignition is on, but the engine is off. Watch the check engine light closely.

It will flash, pause, flash flash, long pause and repeat. This means code 12. That is normal. It will repeat this three times. The first segment before the pause is the first number, remember it, after the pause is the second number, remember that. This will happen 3 times and then go to the next code if there is any. If there isn't any other codes it will go back to flashing code 12.

For example: flash, flash, flash, flash, pause, flash, flash is code 42
flash, flash, pause, flash, flash, flash, flash is code 24.

Let us know what code you come up with and we will try to help you solve the problem!

 

If the engine is still running fine when the light comes on...it is more than likely an EGR code...especially if people where messing around the EGR temp switch which are really touchy.

Pull the code and please respond to what it is.

DUB

 

I was thinking error code 32 before I saw DUB's response... Typical symptoms.

You can retrieve the error codes by using these methods:

http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm

What they mean:

http://forums.corvetteforum.com/1576116036-post35.html

 

well,

most folks Service the Engine.....Soon.

 

Thanks for all the quick responses. Will test later today with paperclip for experience sake only. Already made appointment for service for whatever needs to be done properly.

There seems to be a lot of intelligent Vette owners in this forum. You should get together and give classes in every state. Kind of a "Corvette 101 for newbies".
Thanks again
Joe

 

dustyjoe 57,

Not knowing if you know this or not...so excuse me if you do know this.

Like I tell many of my customers who "freak-out" when a Service Engine Soon" light comes on....not writing that you are "freaking out".

I ask them.."Is the car still running fine at idle...So well...that if you did not see the light...you could not tell something is wrong??" The reason I ask them this is that many of the Codes that Cliff gas offered up for information are codes for emissions and fuel economy along with other "things"...depending on the year model...and have nothing to do with the engine being able to run well enough to drive. These codes are important...and I am NOT writing that they are not important...BUT...there are some Codes that ARE REALLY IMPORTANT...and if they come up...the computer will put the engine in a "flood" mode...so-to-speak...and dump as much fuel in it as possible.

Just to let you know...just in case you did not know this already. If the Service Engine Soon light is on and the engine is fine...it is a code for like I wrote emissions/fuel economy usually.

If the SES light is on and the engine is putting out black smoke and the engine will NOT idle well unless you rev it up to 1500+ RPM...then this is an input sensor of some type that has a problem...and needs to be taken care of ASAP.

NOW...(Imagine this) You are on the way home from a vacation and the SES light comes on and when you come to a traffic light and stop...you notice that it will not idle and you have to rev the engine to keep it running smooth and you are 50 miles from home....and the area you can feel does not have anyone who can fix it....so you do not want to stop.

Well..if you are using an Interstate highway to get back home...you can drive at 50+mph ..chances are that you will get back home and not miss a beat. This is because GM basically had 2 choices when choosing a format if "something bad" were to go wrong. SCENARIO 1: Keep the fuel delivery and timing , etc at a setting that would allow you to drive through downtown New York City on a Friday at 5 o'clock on a holiday and not have any problems....OR SCENARIO 2: Dump as much fuel, etc as possible so if you were in the Mojave Desert in the middle of summer...you can drive through the desert and get to a town at high speeds....because trying to drive through the desert at inner city speeds could be life threatening....so GM chose the later of the two.

So knowing this...if you ever experience a major issue...just remember that you can drive the car...you just have to keep the revs up because it is going to need as much air going through the engine to keep it from loading up on fuel and fouling out the spark plugs. So at a stop light...but it in neutral and rev the engine until the light turns so you can go. Just in case you might need it one day.

And OBVIOUSLY...this is also taking into account that your are NOT overheating..or running the engine with little to no oil, etc. COMMON SENSE does come into play here on making sure you can actually drive the car and the SES light is not being caused by another system failure due to lack of maintenance, etc.

DUB