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OBD1 Codes '95 Buick Century

09-03-2009, 08:26 PM
Just bought a Buick. Need some advice before tearing the whole thing apart. Need to pull codes from the PCM if it's possible.

Car is a 1995 Buick Century with a 3.1L engine and OD automatic transmission. This is a transition vehicle as far as OBD is concerned. It isn't OBD1 nor is it OBD2. It has a 12 pin ALDL under the dash. There are three wires to the ALDL. An orange wire goes to the A pin. A purple wire goes to the K pin. A black with white stripe wire goes to the M pin. There is no connection at the B pin therefore the paper clip trick doesn't work. There aren't enough wires to the ALDL for OBD2. :runaround:

How does one pull trouble codes from this system? There are code scanners available but the specifically exclude the '95 Buick Century. :screwy:

Is it possible to build an interface that will work with this system?

Thank you all for any information.


09-04-2009, 12:02 AM
Sounds like its a GM-1 connector.

09-05-2009, 01:31 AM
Ok, it sounds like a GM-1 but what is a GM-1? :confused: I haven't seen any mention of that connector in all of my hours of research in manuals and on the internet.

Do you have a pin out of the connector with descriptions of the function of each wire? It might help me get to the bottom of my transmission problem.

Thank you,


09-09-2009, 07:59 AM
94-95 GM vehicles require a scan tool to pull the codes. There is no paper clip trick that will work.

09-12-2009, 03:56 PM
As I stated in my first post, the paper clip trick won't work.

What scanner will work with the setup described in my first post. There are three wires, one orange, one purple and one black with a white tracer. There is no wire to the "B" terminal.

Why is it so damn difficult to find information on this arrangement? It is in a stock, clean, 1995 Buick Century with a 3.1L engine and a 4T60-E transmission. What is the great secrecy about this car?

Google and Yahoo have nothing but sellers who want money but won't share any information. They won't even, in many cases, tell you that their scanner will not work on that particular car.

09-12-2009, 05:00 PM
All you need is a GM OBDI scanner. You can find them for $30. Acutron makes one for about that price.

09-12-2009, 10:22 PM
All you need is a GM OBDI scanner. You can find them for $30. Acutron makes one for about that price.Actron does not make a scanner compatible for OBDI & OBDII for $30. They may have a 'code reader' for that price, but not a scanner. You would need an Actron CP9150, or CP9190 to scan live data & retrieve codes on this particular vehicle. I use a Matco Tools 9640B professional enhanced scan tool on the 94-95. It is actually a KAL or Actron built unit. Of course, the Tech 11 and Snapon MT2400 with key #7 will work, but are much higher priced

09-12-2009, 10:35 PM
I don't think I had looked before my first post but I did look later for the OBD certification on the '95 Bick Century. It is certified to be OBDI. A lot of people keep on with the wrong version of OBD when they discuss readers or scanners that will work with this system, that is OBDI.

Thank you all again for any pertinent information, links, software or hardware sources or pointing to a scanner or reader that will pull the codes out of this car.

09-13-2009, 07:13 PM
Sorry, they make a "code reader" for $30.

09-15-2009, 02:07 PM
most code readers will not work with 94-95 GM cars without the wires in terminals A and B. They require the ground terminal to be there to put the car in diagnosic mode. The "tool" provided is just a jumper in a fancy plastic case, and they come with a book (what you're actually paying for) to decipher the flashes of the CEL.

12-08-2009, 10:52 PM
I'm curious as to your final solution. Did you purchase a code reader? which one? how much?

I also own the same model vehicle and yesterday the service engine light came on although it went out again this morning just a mile before parking it at work. Thanks!

03-20-2011, 12:59 PM
ANY ONE???? I have this same issue

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