[tblazer]

Yesterday, out of the blue, my "Service Engine Soon" dash light came on. It displays continuously, (not flashing), which cause me concern?
My '99 SS has always been serviced by a dealership and I've never had any sort of electrical, ignition or fuel delivery issues. I don't race or mistreat my car, but simply enjoy showing it at local car shows and only have 54k miles on it.
Can anyone offer suggestions as to what the problem may be? I do intend to bring it back to my dealership this week. I drove it this weekend over a fairly long distance, (120-mile round trip), during which the dash light came on. My owners manual suggested a couple things to check, (e.g. make sure the fuel tank cap was secure, make sure all essential fluid levels are adequate, look under vehicle for any fluid or coolant leaks, etc.).
I just want to be sure that I haven't overlooked anything. I've always looked to my trusted Gurus' here on Camaros.net for feedback on any and all unsolvable issues I have with my Camaro.

Many thanks,
tblazer:hurray:

 

[SilverSS1969]

I'd find someone that could read and pull any codes that the car might be throwing. That would have pin point the issue. Some auto store will pull the codes for you but many won't erase the codes anymore due to liability.

 

[COPO]

Did you happen to purchase crappy gas?

 

[tblazer]

COPO; ..thanks for the reply. As a matter of fact I did purchase gas on my trip from two different vendors I normally don't get gas from. If indeed "crappy" gas is the culprit, how long do you think it will take for my engine to clear out the residue gas? You really think crappy gas will cause the fuel sensor & others related sensors to respond by lighting up the "Service Engine Soon" light?
tblazer

 

[tblazer]

SilverSS1969; ..thank you for replying. I believe you've helped me out on several previous occasions with issues. I am not at all opposed to paying my dealership, (done regular business with them before), to do a diagnosis. Matter of fact this is precisely what I plan to do this week. I just hope that they can pinpoint the problem purely from a "piece-of-mind" perspective. I don't have all the code reader equipment and am not proud to admit that I am not that savvy when it comes to diagnosing the vast array of electrical complications of today's modern vehicles. Again, I enjoy showing my Camaro at local shows and am a left over 50's generation chevy buff from the tri-five years!

Thanks,
tblazer

 

[Gar's67]

Recently pulled a P0420 code off my 2005 Suburu Legacy...light was on. This code stands for a catalytic converter. I had the converter replaced several years ago under warranty. Very expensive fix however so thank goodness for the warranty. Anyways....it turned out to be "too much motor oil" in the engine. Had the shop that did the oil change remove some oil, and, within a day or so, the light went off. Used this $50 scanner to get the job done:

 

[PowerWindows]

It could be something as simple as "catalytic converter efficiency" which is what your rear O2 sensors measure. I had that one happen a few times with my 02 Z28. Doesn't affect the performance.

 

[autotech21]

The first thing to do is to have the code pulled. You can check out everything on the car and all you will do is waste a lot of time. As far as bad gas setting the code without having driveability issues is extremely unlikely.
Go to Autozone or Orieliys and have them pull codes for free. When you get the code let us know.

 

[Everett#2390]

Clean out of crappy gas can take about three tankfuls.
If the problem cures itself, PCM will erase the DTC.

 

[Steiner]

It might indeed be the catalytic efficiency code if the car has over 50k on it. They have the limit set pretty tight so it'll set even if the cat is still good. Mine was getting it so I started moving oxygen sensors around and clearing the fault with my laptop to see if it would follow a sensor (you get a different code based on what bank is failing) but didn't get anywhere. Checked the waveforms with some logging and they appeared to be fine, fuel trims were fine as well. Spent $100 and changed out all four of the 02 sensors (versus $200 for a new cat) and it hasn't come back in quite a while. I've read that with the LS1 the oxygen sensors wind up being pretty much a wear item and need to be replaced well before the emissions warranty is up. The factory tune is very rich at full throttle to protect the engine but it is hard on O2 sensors (and cats).

 

[Mark C]

The SES lamp is emmissions related only. Unless its flashing which means you have an overly rich exhaust stream that could cause catalytic converter damage (or even set it on fire). Could be as simple as you forgot to screw your gas cap back on tight, to a loss of catalytic converter efficiency (the P0420 code). If it happened within an hour of getting gas I'm betting on gas cap. If it happened a day or so later it's probably an O2 sensor issue. Nothing to really worry about unless it starts flashing, or you have a state emmissions inspection coming up. It can take a week to get it to reset on its own after the problem goes away depending on how much and how long its driven.

 

[rj68RS]

We had an SES on wife's Burb once, ran the code and found P0141 pointing to 02 sensor, bank 1 failure. Climbed underneath and found the weatherpack connector had some how come. Blew it out, snapped back on, all s been good for 5 years.

Anyone with basic cars skills should have a inexpensive OBD/OBDII code reader. I have an Actron that picked up on sale for ~$60.00. It has easily paid for itself many times over.

 

[Everett#2390]

Read Harbor Freight flyers and ads. I got mine for $30.

 

[dnult]

Read the codes - there are literally hundreds of possibilities so what others have seen on their vehicles really doesn't help you that much.

Around here you can go to auto-zone and they'll read your codes for free. Just beware - get the code number not their description of what it means.

 

[tblazer]

:hurray: Thanks to all for your responses to my "idiot light" issue.
As it turns out I bit-the-bullet and brought to my trusted dealership to have a complete engine diagnosis done.
The culprit was a faulty 02sensor. Two codes revealed a problem (I believe, if I understood the service advisor say) targeted a combination fuel/air delivery problem. At any rate my problem was solved and the cost was reasonable. I would have spin my wheels for awhile trying to find the problem.

Thanks all for you contribution of expert advice.

 

[dnult]

FWIW, many people shudder at the thought of working on OBDII (post 1996) engine controls, but personally I prefer them. OBDII is really good about giving fault codes that are fairly specific. Before OBDII a minor problem would throw you a half-dozen faults making it a bit more difficult to narrow down the problem. IMHO, the money for a diag tool to read and clear codes is worth it if you're a DIY guy.

In any event, glad you got it fixed.

 

[shdwjim]

dnult is absolutely correct. OBDII makes it much easier to diagnose problems on the newer vehicles. There are many sensors throughout the systems on todays cars that can cause the engine light to come on. As a mechanic I can tell you that there is almost no way to figure out what sensor is causing the light to come on without using a code reader. Anything from EVAP systems, misfires, EGR, catalyst and O2 systems, and many other problems can cause the light. Code readers don't always give you the answer but they do point you in the right direction.
Sorry to ramble on but most importantly I'm glad to hear that you got everything squared away without breaking the bank.
Jim