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How do I read OBD-1 codes =16 pin connector


jerryls
07-27-2005, 12:34 PM
I've read all sorts of threads on this, but have not found an answer. I have a 94 3.8L VIN-L series. It has a 16 pin connector, but only pins 4,5,8,914 and 16 are used. I have an OBD-II reader that gives me an error when I try to scan the codes. Where can I get definition of this interim OBD operation
Thanks,

93buicklesabrelmtd
07-27-2005, 09:34 PM
I've read all sorts of threads on this, but have not found an answer. I have a 94 3.8L VIN-L series. It has a 16 pin connector, but only pins 4,5,8,914 and 16 are used. I have an OBD-II reader that gives me an error when I try to scan the codes. Where can I get definition of this interim OBD operation
Thanks,

This says its from 1985-1994
http://www.geocities.com/dann8785/serviceenginesoon.html

This is what my 93 ODB1 looks like
http://autorepair.about.com/library/ts/obd-i/bl-dtcs-31a.htm


If you know what wire each #number stands for then I would..

Try to find the Ground teminal whatever # or letter it is.
Then try to find the Diagnostics terminal (same way), then jump those.
See what happens.... This may work...

HotZ28
07-27-2005, 11:12 PM
http://www.automotiveforums.com/vbulletin/showthread.php?t=307153
New Info: 1995 non-OBD-II 16-pin

jerryls
07-28-2005, 02:37 PM
This says its from 1985-1994
http://www.geocities.com/dann8785/serviceenginesoon.html

This is what my 93 ODB1 looks like
http://autorepair.about.com/library/ts/obd-i/bl-dtcs-31a.htm


If you know what wire each #number stands for then I would..

Try to find the Ground teminal whatever # or letter it is.
Then try to find the Diagnostics terminal (same way), then jump those.
See what happens.... This may work...

Thanks, These are good sites, but both assume a 12 pin connector with a means of diagnostic pin to short. The 16 pin OBD-1 doesnt seem to allow any jumpering to have any lights blink.
I think I would have to read the serial data line.

jerryls
07-28-2005, 02:44 PM
http://www.automotiveforums.com/vbulletin/showthread.php?t=307153
New Info: 1995 non-OBD-II 16-pin

Thanks,
I read through this site and see the pin definitions of the 16 pin 94 Lesabre version. I think I can write a simple program to read the serial bits into a laptop. I dont know if it's worth trying to decipher it without some definition of what's transmitted. There may be all sorts of preamble bytes transmitted prior to the codes. If GM lists it somewhere, then I would write the program and put it on this forum.

padriver
07-28-2005, 03:16 PM
Thanks,
I read through this site and see the pin definitions of the 16 pin 94 Lesabre version. I think I can write a simple program to read the serial bits into a laptop. I dont know if it's worth trying to decipher it without some definition of what's transmitted. There may be all sorts of preamble bytes transmitted prior to the codes. If GM lists it somewhere, then I would write the program and put it on this forum.

Here's some information that should help you:

http://pweb.de.uu.net/pr-meyer.h/binaries/ALDLstreams.zip

The archive contains lots of data stream formats and protocols. For your car, check out data stream A221 specification.

HotZ28
07-28-2005, 03:57 PM
In 1995 GM changed to OBD 1.5. Some late 1994 models are also OBD 1.5. For these (OBD 1.5, 16 pin ALDL) short terminals 5 & 6.

Turn key on, but do not start engine. Find and Short terminals with a paper clip. The check engine light will begin to flash. The ECM (computer) will display a "code 12" by flashing the "service engine soon" light, indicating that the system is operating. A code 12 is simply one flash, followed by a brief pause, then two flashes in quick succession. This code will be flashed 3 times. If no other codes are stored, code 12 will flash until the diagnostic terminal ground is removed. After flashing code 12 3 times, the ECM will display any stored trouble codes. Each code will be flashed 3 times, then code 12 will be flashed again, indicating that the display of any stored trouble codes has been completed.

:cheers:

amplifier28
07-31-2005, 02:49 PM
Hey "hotz28"

How can we short terminals 5 & 6 if terminal 6 does not exist and is not used in a 1995 Buick LaSabre?

HotZ28
07-31-2005, 07:43 PM
OK, so you have the bastard. Short pins 4&9 and see what happens.

jerryls
08-01-2005, 11:32 AM
Here's some information that should help you:

http://pweb.de.uu.net/pr-meyer.h/binaries/ALDLstreams.zip

The archive contains lots of data stream formats and protocols. For your car, check out data stream A221 specification.

It looks like there are modes that the ECM can be put in. I don't see an input pin for the scanner to select a mode. Possibly the serial pin(9) is bidirectional? Else the ECM just spits out all the information in a loop? Do you know where this may be further defined?
Thanks

padriver
08-01-2005, 11:54 AM
Yes, there are different operating modes. Pin 9 is indeed bidirectional and used for getting the data as well as switching between modes.

Here are some links to schematics of interfaces:

http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm
http://pweb.de.uu.net/pr-meyer.h/aldl.htm

If you google for ALDL 8192 you should find quite a few sites with further information. Some time ago, I started a similar project, but I haven't finished it yet because my car started to give me trouble and I needed quick diagnosis, so I decided to buy a scan tool.

jerryls
08-01-2005, 12:57 PM
Yes, there are different operating modes. Pin 9 is indeed bidirectional and used for getting the data as well as switching between modes.

Here are some links to schematics of interfaces:

http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm
http://pweb.de.uu.net/pr-meyer.h/aldl.htm

If you google for ALDL 8192 you should find quite a few sites with further information. Some time ago, I started a similar project, but I haven't finished it yet because my car started to give me trouble and I needed quick diagnosis, so I decided to buy a scan tool.

Thanks,
This is all very good information. I looks like a lot of work has been done before on this. It's alot of effort to read an interim code. The OBD-II readers can be purchased for <$100.00 and work on all cars after 96, so maybe I'll bite the bullit and just take the car to a dealer, and have them read the codes.

HotZ28
08-01-2005, 03:52 PM
Take it Auto Zone and see if they can do it. If not Auto Zone, surely some of the auto parts stores can scan it for free!! My scanner will do it!!

mcqueary
08-01-2005, 06:19 PM
Hi HotZ28. So what kind of scanner do you have that reads OBD-I codes from the 16-pin OBD-II connector on a 1995 Buick Lesabre? I have tried two different generic OBD-II scanners, my own and one at a shop, and they both report bad data link. Are you using the GM Tech I or Tech II scanner? Thanks, Tom.

HotZ28
08-01-2005, 08:57 PM
I still have an old Snap-On MT-2500 scanner that I bought used several years ago. I also had to get the OBD II connector with a special key for OBD I readouts. I forgot the key number, but a Snap-On dealer should have the info needed.

I currently use the Genisys Kit with Pathfinder 2003, Asian Import 2003 and ABS/Airbag 2002 Software.

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