Service Engine Soon - warning light
 

*EDIT* 1989 Chev G20 van, 305.

Does anybody know what this means? I do service at regular intervals, though maybe I'm missing something.

I just wish I knew if the warning light had any actual computer brains behind it, such as some sort of trouble code stored somewhere. Not sure what the state of the art was in '89. A Google search was disappointing, oddly enough.

Not a clue what it means other than the ECM has noted that a sensor was outside the parameters. Even with the C4 Vettes after 85, IIRC, you can plug it into a scanner and see not only code but data stream. I know my 91 can do it.

So, what you are saying is essentially "Something is wrong". What, why, when, etc, etc, is hard to say. It might trigger a code to say something is FUBAR or that it noted something was not right when a certain set of conditions is met. Without more knowledge, it is going to be very hard to say. We can throw money and parts at it if you have more money than brains but I wouldn't think you would.

Why don't you start with the first step. Go to Autozone and have them scan it for you?

http://www.e38.org/e32/bmw%20code%20defaut.pdf

Scan code first and clear it and see if it comes back. In the meantime, go look up what the code really means and not what the scanner said. The scanner points you in a direction. Doesn't mean it is absolutely right but look that way.

My 99 C280 said the BOTH sides had lean O2 sensor readings. Was it correct? In a sense. BOTH sides were lean because the MAF said there was less air than there was and the ECM cut the injector pulse width and thus the O2 sensors reported that BOTH banks were lean. BOTH sensors going out at the same time is highly unlikely as opposed to 1 MAF.

Also your injectors, if you are like most people, have never been removed for cleaning and testing. I do that every 100K for daily drivers and every 3 years for the Vette, ATVs and Jetskis.

I think "Service Engine Soon" = "Check Engine".

What car is it? The cars in your sig don't match the year.

X2. Could mean anything based on manufacturer.

1989 vehicle id call a check engine light cost of doing business. Will say it might go away if you fix tons of drivability concerns over time. If the vehicle is exhibiting no noticiable driving problems id ignore it. I have a service engine soon lightin my 99 van now that i treat as an old trusted friend i can depend on to join me.

The light went out in my 1989 van after i replaced a lot of emissions controls, AND after i had a small engine fire.

Oh jeez. I had originally put the brand and model in the title line but had to start over and forgot that. It's a Chev G20 van, '89, 305.

I'm pretty sure you are correct. When I was in mechanic school they taught us about gasoline EFI with OBDII. On an OBDII system the light is required to go on when something emission related has gone out of set limits. I believe manufacturers are also allowed to have it go off in the even of other things related to out of limit engine performance. On a pre OBDII system, who knows? They didn't really cover that in school. I do know that OBDII standardized certain codes (but unfortunately not all, hence proprietary diagnostic software) and the method of extracting them. Things were more varied before OBDII.

I'd say that scanner would help determine what the issue is. If it is emissions, decide for yourself. With EFI it adjusts itself so SOTP isn't reliable.

Agreed. Pulling codes tends to be one of my first pieces of advice for anything from which codes can be pulled, or as an electrical engineer friend from college used to say, "Ask it where it hurts."

89 is OBDI I think. You should be able to jump a couple of the terminals on the connector and get the code from the number of flashes from the Service Engine light.

89 no scanner, should be obd1.

My 89 chevy the service light turned out to be the egr valve was plugged, but that was a 4.3 throttle body injection. You probably have a similar setup

My 91 is OBD1 too. We can jump the terminal to get the code. With scanner you get more data for diagnosis though. He'd need to find the ALDL which is probably under the driver side dash.

On a BMW and some others SES = Check Engine.

However, my 1992 Dodge has a check engine, and a service soon light. The service soon light comes on at random markers in the ECU that are triggered by OBD1s very rough guesstimate of mileage. There is a list of definitions somewhere, I think the major service points were listed in my owners manual. The 120,000 mile service (light came on at like 133,000 on my truck) was something like "change ignition components, clean EGR tube, clean throttle plate" and then I used my friends snap-on Modus with OBD1 software to reset the light.

It's a Chevy G20 van, MY 1989 so I am THINKING it is similar the slightly older F body cars with TBI. Only CMAC can tell me if it is TBI. If it is there might be hope to do diagnostics.

http://www.ih8mud.com/tech/tbi/wireTBI-1990b.gif

If it uses a 1227747 ECM which is capable of being tuned, you might be able to really get some serious data off it. TunerPro and TunerPro RT - Professional Automobile Tuning Software

GM has had what amounts to OBDI since the early '80's. While a typical OBDII scan tool will not connect to it, there are plenty that will. In '89, depending on GVWR and state of initial sale, the van could be either carbureted or injected I believe. Either would be computer controlled (unless there were some really primitive carb'd units that I never saw being in CA).

In either case, as mentioned, the best be is to "ask it where it hurts", and this is done by reading the code(s). Once you have an idea what isn't right, you can start looking for what is wrong.

MV