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Ron Z.
Ron Z., - Saturn Tech -
Category: Saturn
Satisfied Customers: 18954
Experience:  18+yrs experience. State Inspector and Saturn Diagnostics
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2002 saturn sl1: why is the service engine soon light on for

Customer Question

why is the service engine soon light on for my 2002 saturn sl1
Submitted: 5 years ago.
Category: Saturn
Expert:  Ron Z. replied 5 years ago.

Welcome to JustAnswer.com! My name is DriveFast71(Ron) and I will do my best to answer all of your questions completely and accurately.


 

When the Service Engine Soon light comes on, this is the on-board computer's way of telling you it sees a problem in one of the monitored systems. Unfortunately, there are litterally 100's of parts and sensors monitored in various systems, and to take a "guess" as to which part/sensor in which system is faulty, is virtually impossible. However, if you are not experiencing any drivability issues such as skipping, stalling, shifting problems, etc, then more than likely, the problem is going to lie in the EVAP (emissions) system. Very commonly, this could be a faulty, loose or missing fuel cap or even putting fuel in while the vehicle is running. Check the cap for any cracks in the rubber o-ring on the underside. Check the fuel filler neck for any signs of chips or debris. Check under the vehicle, around the area of the fuel tank and the EVAP canister looking for any vacuum lines that have dry-rot cracks, holes or loose/missing connections. If these all check out, then the best thing to do at this point is to have the "p-codes" read from the on-board computer. These p-codes are what is used as a "starting point" for the diagnosis and will tell which part/sensor in which system has the fault. There isn't a Mechanic on the planet that can tell you what is wrong with the vehicle just by "looking" at the Engine Light. Every single Mechanic's first course of action WILL be to obtain the p-codes. Once you get these p-codes you can more accurately and efficiently diagnose the problem and then make the repair. You can have these p-codes read FREE (except in California) at any local "big chain" part store (ie. AutoZone, PepBoys, Advanced, etc). If you still need help after retrieving the codes, you can bring them here, and any of our Techs can walk you through the diagnostic procedure, and then even help you make the repair if you feel confident enough to try.

Customer: replied 5 years ago.
need more information
Expert:  Ron Z. replied 5 years ago.

Like what kind of information did you need? Feel free to ask specific questions...

 

Customer: replied 5 years ago.
well, if it is not the gas cap, and the car seems to be running fine what else might it be, it does have 108,000 miles on in and I have had the oil changed and the transmission fuled flushed and filled again, and they checked all the other fluids and they are fine, the wind shield wippers were also changed
Expert:  Ron Z. replied 5 years ago.
Well, as stated above: if you are not experiencing any drivability issues such as skipping, stalling, shifting problems, etc, then more than likely, the problem is going to lie in the EVAP (emissions) system. Unfortunately, there are litterally 100's of parts and sensors monitored in various systems, and to take a "guess" as to which part/sensor in which system is faulty, is virtually impossible. There isn't a Mechanic on the planet that can tell you what is wrong with the vehicle just by "looking" at the Engine Light. Every single Mechanic's first course of action WILL be to obtain the p-codes.