"Service Engine Soon" on Buick LeSabre?

[Guest]

Do anyone know what it means when the orange "Service Engine Soon" lamp lids on a LeSabre 1987? It seems to switch on and off regularly.

[JohnO]

It means to scan the computer in the car and find out what is causing the light to go on. Autozone will scan your car for

free. It's one of these things where you usually don't have to do it today or tomorrow, but get it done in the next week or two.

[Guest brh]

Check your manual. My mother in law's Buick has this feature but I can't remember how to reset it. Previous post is correct its to remind you of regular service. Oil change and such.

[Guest]

AutoZone might pull the codes "for free", but they are doing that so they can sell you the parts to fix it yourself. You might well have some codes which set due to other codes setting, so you could get a whole string of codes when the real cause is only one code that set the whole thing off to start with.

Also, don't expect to take their list of codes into a repair shop or dealership and say "I want these things fixed". First thing that will probably happen is that you'll pay the diagnostic check out time for the tech to determine what codes are in the computer according to their scanner, then the parts estimate can be made and things progress from that point.

A recent customer kept having a battery light come on in her late model Malibu. She took it to a private repair shop who obviously spent quite some time running through the electrical diagnostics of the vehicle before determining that the PCM needed to be replaced. They also installed a private brand of rebuilt alternator too, in the process. When the light did not go out with the fresh reman alternator, more diagonstics led them to the PCM (as evidenced by their schematics in the front seat of the car) so they sent her to the dealership to order a PCM, which we gladly did.

When the PCM was received, the car came back to get it installed. The technician also performed a charging system check and the previous rebuilt alternator did not pass, even with the new PCM. On that car and many newer vehicles, the Powertrain Control Module turns the alternator on and off, charge wise. We priced a Delco alternator for it and they decided to get another reman from the repair shop. Their second (that we know of) rebuilt alternator did turn the battery light off, until she got a ways down the road and it came back on. A charging system check again showed the rebuilt alternator to be not up to snuff.

By this time, the car had been in our shop for about 3 days and for untold other days at the private shop prior to that. When I went in to work the next afternoon, the technician had brought the "original" core in for the Delco reman alternator we finally got to sell--it was also the one that had been on the car from the factory. The battery light went out and stayed out.

If you figure in a rent car expense of about $35.00/day from us for 3 days, the fact she lived about 35 minutes away from the shop, and that the private shop had spent much longer to diagnose the alleged problem, plus the expensive PCM that really was not needed (the diagnosis of the private shop), plus what she paid them for their work and time, it certainly would have been much less expensive, all total, to have brought it to the dealer first and paid for the more expensive AC-Delco reman alternator and labor to install it and do the charging system check.

I know that people might have sticker shock from some dealership prices, but considering the new lifetime warranties on many things (parts & labor if we install them), you might pay a little more up front but you don't have to pay it again for a long time. In this particular case, the customer could have had her car back the next day instead of being out of it for something like a week, all together.

So, not to belittle AutoZone for their sales pitch to get you to their store with the "hook" of pulling the codes for free, but use that only as a general idea of what the problem(s) might be until you get it to a repair facility which a higher quality scanner and someone who knows how to interpret what the codes are and how they interact--whether at a dealership or a high quality independent shop, notice I did NOT mention chain store repair shops, as a general rule.

It's one thing to be able to pull the codes, but it's a whole 'nuther deal to be able to watch the individual sensors and what they are doing in real time observation, as the GM diagnostics will do, to get to the bottom of the whole deal that made the light come on in the first place. On OBDII vehicles, even a fuel cap that is not on securely will turn on the light (due to monitoring of the evaporative emissions system).

Just some thoughts . . .

Hopefully the malfunction will not be too bad. On most vehicles which have the oil change monitor and the later Oil Life Monitor systems, or even the oil level monitors, there should be a different light for that as the Service Engine Soon (or similar) light is typically dedicated to just powertrain control issues which relate to the emissions system also.

One customer called in and said that her Service Engine Soon light had come on and so she checked the oil, put some in, and the light didn't go out. Her boyfriend told her how to unhook the battery for a short while to clear the codes, which she did, but the light came back on. She wondered "What Next?"

Enjoy!

NTX5467

[Guest Shaffer]

I know all about that. Almost every 1980s GM car we have ever owned, the "service engine soon" or "check engine" light was on. The light is the computer telling you there is something wrong with the car. In can be a sensor, such as a oxygen sensor, stopped up converter, TPS sensor, MAP sensor, etc. Yes AutoZone will check it for free, or for about $25.00 you can buy the tester and book yourself. AutoZone can give you the key only, but you have no way to tell the codes without a book. However, I have a tester and book, so if you check it and give me the codes, I can tell you the problem. I have one, because most recently the "service engine soon" light was illuminated on my moms 1989 Pontiac Safari wagon. Most places charge $25 to just test it, but I bought the tester at AutoZone for $25. You plug it into the connector under the driver side dash panel on most GM cars. Ours was showing a bad oxygen sensor and TPS sensor. We got those replaced and it took care of it. It could be a thousand of things, so I would check it first. if you just get the key, insert it into the connector toward the plugs on the right hand side. Turn on the ignition. You light will first flash- one blink, then a pause, then two fast blinks. Then will repeat for three times. The following blinks will be the problem. For example - a blink-blink - blink would be a code 21. Or a blink-blink-blink-blink - blink-blink, would be a code 42. Each code will blink in three different intervals. Sounds complicated, but it is simple. When the code or codes are all shown, it will go back and do the code "12" again. This means it has shown all problems. It could be something as simple as an oxygen sensor. Good luck.

[Guest Shaffer]

Forgot to mention that "service engine soon" or "check engine" - which means the same thing, has nothing to do with the oil level. It is usually concerning the pollution controls.

[Guest Shaffer]

However, on some late 90s and newer cars, GM at least, have a "check guages" light, which may mean low oil level, low fuel, excessive temperature.

[Guest]

"Kids, don't try this at home!" Anyway, let me put in my two cents worth.

Over thirty years experience GM dealership parts department, car hobbyist for thirty six years. Still do not work on my own late model computer controlled cars. Why? Because I don't like changing parts and still having the problem there! Cannot tell you how many people that have come to the parts counter wanting to buy a (fill in the blank) because his or her friend said that will fix the SES light. I ask them as a matter of habit if they scanned the ECM, PCM or VCM and followed the diagnostic charts in the service manual depending on the vehicle, and probably 50-75% of the time the answer is no, but that fixed their friend's car before. So I politely try to convince them that they need a good system check out, either from our Service Department or a good quality Independent Service Facility. If they insist that they want the part, I inform them that once they buy it, they own in and I will not take it back. The next question is "Why not?" My answer it "Would you buy a used part at a new price, which could be damaged from improper installation or a voltage spike?"Well, this usually gets their attention!

It's not that I am trying to drum up business for our dealership, it's that I don't want the hassle of arguing with the customer after telling him that he now has a spare part for his collection!

So many things can cause a SES light to come on, even a dirty or corroded wire connection at a sensor. At one point in the mid 80's, GM had a problem that the coolant sensor would seep coolant between the plastic and metal body, and due to the low voltage this sensor works on, the coolant would work it's way back up and into the ECM. Try explaining to a customer why the computer is leaking anti-freeze!

Good luck

[NTX5467]

I've also been in the GM dealership parts area for quite some time too and will concur with those comments. I might also add that when someone calls up wanting a price on a sensor a mechanic shop or auto supply has told them they need and the dealership parts person tries to find that particular item in the parts database, only to discover that their year, vehicle, and engine combination does NOT have that part, it does tend to elevate the parts person's "oil pressure". Instead of pulling the codes and going from there, people always want a "magic bullet" fix like their friend got (nothing wrong with that at all) but it doesn't always work that way.

When I'd get one of those calls/inquiries on a non-existent part for their vehicle's emissions system, I'd ask them if they had pulled the codes. Their reply indicated that they didn't know about those things and were going on the "expert advise" of their "advisor". My comment was to the effect that, just as in the "old days", several different things can cause the same problem, you can chunk parts at things all day and still not get it fixed. Only difference is that now the parts are expensive parts (usually) and being electrical, are not returnable. That tends to drive home the fact that they need to get someone to look at their vehicle that knows what they are doing. I then would transfer them to the service advisor (I usually tried to have one or more that I would trust with such calls) so they would have a better idea of the costs involved to accurately diagnose their vehicle's situation--even if that vehicle never graced our service drive with its presence.

During the middle '80s when we were deep into "thermal vacuum switches", I found an AC-Delco book on just those switches. It was a great tool to use when the customer did not know what they had or how to determine what they had. In addition to the application charts, it also listed the switches on each GM vehicle and year model in the back. If you wanted to know what switches were on a particular model, year, and engine of Buick, it was all right there.

In the earlier years of computerized vehicles, the codes would usually change yearly as the computers and emissions hardware was upgraded and such. OBDII on the later models standardized that somewhat. So, if you get a book that decoded the trouble codes, make sure it is not just for one year of GM vehicle. Even with the code books you might find at the auto supply, there could be some discrepancies compared to the GM service manual.

Then, there were the callers that inquired what a certain code meant. At least their heart was in the right place, but they never did put that info in the parts books, so I again sent them to the service department people.

At the present time, the closest thing I have to a computerized vehicle is a '80 Chrysler Newport 360V-8 with the Lean Burn setup. Even this allegedly onerous setup is not that hard to figure out. Just as with the GM things, it all works on voltages and resistance. I'll probably end up with a late model or new GM vehicle in the future, but I'm not afraid of the electronics one bit. Just have to understand what you're dealing with. Don't expect me to take an ASE Certification test on those things though, but I'll sell the parts all day long.

Not that these vehicles have to specifically come back to the dealer for these repairs or that a motivated private individual might do them themselves, just don't expect that all vehicles are the same when they can be very different. Having the appropriate GM service manual can be a very good investment to make.

Just some additional thoughts . . .

NTX5467

[Guest]

And they wonder why parts people have gray hair and no sense of humor!! I also am not afraid of the "computer cars", between the four of them we have, the lowest mileage car has 96k, the highest mileage over 200k. Another pet peeve I have is when someone uses a aftermarket (example, Chilton, etc.) repair manual.

Use the genuine manual, for G.M. vehicles contact Helm Inc., the authorized manual source at 313-865-5000. They also have a WATS line, but I do not know the number offhand. It will cost you more, but it is worth it in the long run.

Not to be critical of the aftermarket manuals, but look at the number of pages in their manual compared to the factory printed manuals. The aftermarket ones aren't thinner because the use thinner paper and smaller print!!!!

They are for the do it yourselfer that doesn't want to get in too deep.

The only one I found that was any good was the Haynes series, BUT, my only experience with them was their motorcycle series.

[Guest]

Thanks for all your suggestions! AutoZone has now pulled the codes:

12

No tach signal to ECM. System normal.

32

ECR vacuum control system failure.

34

MAF sensor or circuit fault.

41

Cylinder select error.

or

Cam sensor circuit fault or ignition control reference pulse error.

or

No disctibutor signal to ECM or faulty ignition module.

44

Oxygen sensor or circuit, lean exhaust detected (drivers side on two sensors system).

After all these codes were noted down, we decided to change the rubber connection which holds the PCV valve in place on top of the engine. The old rubber "gasket" was completely worn out, and the PCV was just lying on top of the engine, and not fixed at all, so all air was completely bypassing this system. Whether that is important or not I don't know, since I don't know the function of this valve/tubing system. But what I noted was, that on the way home the Service Engine Soon sign didn't lid even once! It is still to see how long that will last, and so whether the two things are connected at all.

[JohnO]

Glad to see that it seems to be working out. As you probably know they will print out the procedure on how to diagnose. I am

though a skeptic and I agree with most of the content in the prior posts - that to get to the bottom of it you generally need

professional help. It is a bit of a gamble and you have to say to yourself I'll spend X dollars and try to fix it myself. Twenty to

Thirty sounds good to me.

Even the people in the business take a gamble and replace things. On a prior Riviera they replaced the EGR valve and Oxygen

Sensor to correct a driveability problem with a occassional check engine light illuminating - it took numerous trips back

to the garage. The problem really was a purge valve.

valve.