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Ron Z.
Ron Z., - Chevy Tech -
Category: Chevy
Satisfied Customers: 17792
Experience:  18+yrs experience. State Inspector and Chevy Diagnostics
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My service engine light just came on this a.m. in my 1999

Customer Question

Hi, my service engine light just came on this a.m. in my 1999 Chevy Lumina. Can needing a new oil filter cause this to happen? The fluids seem to be fine and no weird noises or anything. But now I'm panicking because the mechanic can't look @ it until next Tuesday. Help please!! Thanks!
JA: Are you hoping to fix this yourself?
Customer: Hi, I'm at work so looking @ this kind of sporadically. No, I can't fix it myself but just want to know it's ok to drive it until I take it in to the shop. And hoping it's nothing too serious.
JA: Is there anything else important you think the Chevy Mechanic should know about your Chevy?
Customer: Yes, I haven't noticed anything else going on that would make me think there are engine problems. The only thing is, in the cold weather, we have to go out and start it up every night and leave it run for 10 mins or so so that the battery charges. Other than that, running very well. This was a complete surprise w/the engine light.
JA: Our top Chevy Mechanic is ready to take your case. Just pay the $5 fully refundable deposit and I'll fill the Chevy Mechanic in on everything we've discussed. You can go back and forth with the Chevy Mechanic until you're 100% satisfied. We guarantee it.
Submitted: 7 months ago.
Category: Chevy
Expert:  Ron Z. replied 7 months ago.

Unfortunately, the need for a new Oil filter (or oil change) will not set the Service Engine Soon light. 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 literally 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 control/recovery) system. Very commonly, this could be a faulty, loose or missing fuel cap or even putting fuel in while the vehicle is running can set the light. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those "universal" or "locking" fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly. Check the top of the fuel filler neck for any signs of damage or debris. Check under the vehicle, around the rear areas of the vehicle, 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 Diagnostic Trouble Codes (aka "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. It's standard diagnostic procedure. Once you get these p-codes you can more accurately and efficiently diagnose the problem and then make the correct repair. You can have these p-codes read FREE (except in California) at any local "big chain" part store (ie. AutoZone, PepBoys, Advanced, etc).

As long as there are no drivabilty issues or shifting issues, then it should be perfectly safe to drive the vehcile. You should however, have the codes retrieved at least to verify. If the problem does lie in the EVAP system, it is strictly for emissions control/recovery and will in no way effect engine performance in any way. If the problem lies outside the EVAP system, it may be a good idea to have it serviced as soon as possible, as prolonged driving with a problem with the engine or tranmission can make matters worse.

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Expert:  Ron Z. replied 7 months ago.


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