Service Engine Soon light

Yep, it's on. Nope, can't check it by shorting the two pins together, because there is no "b" pin.

Apparently, this isn't a fluke either, since even the cheap code scanners (You know the *coughACTRONcough* ones... the ones that you could just short the two pins w/ a paperclip and accomplish the same thing...) don't list the 1994 Pontiac Grand Prix SE as a model that they'll work on.

Apparently, GM wanted this car specifically to be brought back to the dealer for any ECM related services...

Obviously, it's OBD-1. I just really would like to find a way to check the damn Service Engine Soon light, since it's on all the time now. I want to know why, and fix it. Oddly, it's nothing affecting fuel mileage, my wife (new driver) averages 24.5 MPG with it, still above the EPA rating.

BTW, it's a 3.1 MPI model.

Also, can the ABS service light be checked through the diagnostic connector? That comes on occasionally too.

Yeah, the 1994 model year OBD1 is slightly different than earlier models. I ran across this problem on a 94 buick. Have you tried advance, maybe they can scan it out? I think its the beginnings of OBD2. When I went to tech college, we had two GM Tech 2's. they are cabable of reading anything. Maybe try there. At our school, all you would pay for was parts. If you provide your own, they would repair your car for nothing. My instructors were anal about everything too.

I may have just gotten a lead on a scanner from SunPro that works... according to their site it does anyway...

If I buy it and it doesn't work, no big deal, it's only $20.

My last consideration was going to BOCES to get it checked out. It's free, if they'll still do it.

No AutoZone or Advance in the area will touch it, since it's OBD-1 and not new enough for them. They just fired a guy for offering his personal scan tool to a customer on loan, no money or anything. And he was off the clock, but he did it in the store, which still goes back on the store, since he had his shirt on still. (Uniform)

What would it cost to go to the dealer and get it checked out?

Also, maybe a link to a manual showing test procedures for the various sensors and such?

I'm so used to working on my Honda.. everything is right in front of you...

Any competent repair facility with either a Snap-on scanner or Tech-1 can scan your car for around $40'ish bucks. Many will roll that back into the repair bill if you have them do the work.

BTW, I love your signature Dropzone, funny stuff!

Eh, usually don't ever have shops do the work lol.

So, that scanner I was going to pick up won't work. It's good for GM's "up to '93" And specifically states that it won't work on GP's after '93.

Why did GM have to gh3y this one up? It has an OBD-1 connector... it's just missing the B-pin.

Any Autozone or Advance Auto Parts Store will check the cause of the code for NO CHARGE. The '94 Buick is no different than other '94 GM cars regarding the Onboard Diagnostics.

......The '94 Buick is no different than other '94 GM cars regarding the Onboard Diagnostics.

not true man. some 94 and earlier GM cars the OBD1 codes can be retrieved with a paperclip. Thats why the OP says he's missing the "b" pin. In 1994, GM was starting the transition to OBD2. The 1994 model year is still OBD1, but they changed the pin layout of the ALDL making it not possible for you to ground the data line and count SES light flashes to get the codes. Instead a tech 2 or appropriate scan tool is needed.

Thank you for replying to that... I might have been slightly less polite about it. It really annoys me when people post without reading the entire contents of the thread.

Thank you for replying to that... I might have been slightly less polite about it. It really annoys me when people post without reading the entire contents of the thread.

Ha Ha, no problem. What else he doesnt realize is that autozone/advance only scans OBD2 cars. They dont have the capabilites to scan anything else (that I'm aware of). Plus even some 1995 GM vehicles are messed up, half obd1, half obd2. They weren't completly switched over untill 1996.

Let me pull out my old engine performance/drivability shop manual and see what I can dig up for you.

I almost got a friend fired from Advance b/c he offered to bring his scanner from home on his lunch break and scan it for me... As long as he's wearing the shirt/on the clock, he can be fired for doing anything against company policy. (See post #3, another reason I wouldn't have been so nice to that person... I had already stated that neither would do it.)

They don't scan OBD-1 anymore b/c of it's age, and apparently b/c they don't want to give false information based on the code displayed.

They also don't sell the tool I need, apparently.

New Motivation to fix the stupid car: I'd like to get as much money as I can on a trade-in for a 2000 (generation) GTP for my wife.

Obviously, the more things that are fixed, the better it's value will be... unless I go to a push-pull-drag trade at some local dealer. There is one offering $2000 for anything that rolls on the lot right now, under it's own power or not.

Too bad I'm not working at the moment, and can't really afford another bill, especially w/ a child on the way.

But I really would love to get this POS fixed.

Yeah, once they are paid off, its way more economical to just fix what goes wrong. I'm only 700 away from having my GTP paid off. As soon as the holidays are over, It will be mine!

Wanna buy it? Just over 100,000 on it now, I've got a bad drivers side axel shaft, which should be delivered tomorrow (from zzp). Other than that, its a great car!

BTW, tried to dig up my old eng perf textbook, but I think it grew legs. Give me a few more days. I'll see if I can find out how to read these codes.

Aight, looking forward to it.

i have been having the same trouble. new here trying to find out the same thing.where does the b pin in other models go. my manual says that not all models in that year are missing the b pin. i'm wondering if i could trace that b pin on another model i could tap into mine.

Welcome to AF!

This post is rather old, and I am not sure if the OP ever got it figured out. Your best bet is probably going to be to start your one thread and tell us what is happening. And no, there is going to be no easy way of installing a "b" pin into the ALDL short of getting a complete wiring harness from a car with one.

I bought a scan tool and found that the problems were EGR solenoid, and trans gear selector switch (can't remember the right name.)

Never fixed either, didn't really care enough. Since then, I gave the car to my Father, who sold it to his friend, who will probably blow it up.

Thanks for the follow up! How much was the scanner?

Thanks for the follow up! How much was the scanner?


Mine was $600 retail. It's an Actron 9190 complete kit. (I only paid about $300 for it, but that's beside the point.)

You can find much cheaper ones, though. The GP was still OBD-I, it was just a matter of finding a scanner that would actually read from the PCM rather than jumper those two pins. Most of the ones that have an actual readout on them will work, I suppose, as long as it has a connection for the ALDL.