'94 3800: OBD what?

[jarl]

I tried to get my '94 TS scanned for codes yesterday to no avail ("96 and up only" was the answer), and I'm looking into DIY interfaces. However, the information around is contradictory... Is the '94-'95 an ODB2 with an ODB1 connector, an ODB1 that gives ODB2 codes (what would this mean?), or none of the above?

Also, is there a single pinout for the '94-'95 3800 TS? The one on the service manual doesn't match what is in my car, so not even GM has the information straight:

Book (ODB1?):
FE..BA
.....M

My car (ODB1.5):
.....A
..KJ.M

The service manual also says that if you have the 12 pin connector you can jump B&A to read the codes, but -as found elsewhere in the forums- this is not accurate for these cars. So my last resort is making the cable myself (buying a scanner is not an option).

There are several circuits available online to make a serial cable for '94-'95 GM cars, but as far as I can tell all of them talk about a 16 pin connector. Is there any circuit that some of you any one of you have made that you could recommend? Software?

[nicke66]

Yes, there are interface circuits and software available!
94-95 3.8 use the old OBDI ALDL 8192 baud communication protocol as earlier models, but use the OBDII 4-digit faulty codes. It is not possible any more with 94-95 model to flash the codes.

You have to make an interface to get them! The data stream is in the M-pin, and there is ground in A-pin.

You can find circuits to build an interface and the best available software here:
http://www.pontiac-interface.de/
Use Google Language Tools to translate.

I have used the schedule from Meyer, but I guess all of them will work.

[Jrs3800]

The PCM you have in the 94-95 3800 vans are kind of stuck in the middle between OBD1 and OBD2... You have an OBD1 compliant PCM that uses the OBD1 Connector But uses the OBD2 Codes... You have to have a Scan Tool with the ability to read the 94-95 GM cars and or truck platforms.. 1993 was the last year for the Diagnostic flash feature in most GM models... 1994 + in most cases will not have the diagnostic pin in the connector...

My 95 Transport was set up like yours.. My 95 Bonneville is set up the same right down to the same exact PCM, but my 95 Bonneville does have the 16 Pin OBD2 connector...

You need a tool that can read this 94-95 set up... Not all tools can read them...

[tucsondirect]

MAN YOU ARE IN LUCK

i just finished connecting my 94/95 gm to the laptop

if it has an obd2 connector but under hood it says obd1 certified then you need to build a cable The only software i have had luck getting to work is EFILive V4 (i suppose ver. doesnt matter) if you could e-mail me pics of your connector to [email protected] i will see if i can help you out!

[danielsatur]

On an OBD I system, you can count the check engine light for codes!

[tucsondirect]

Originally Posted by danielsatur

On an OBD I system, you can count the check engine light for codes!

im sorry this is simply not correct for these years, you will actually blow the computer! Please be more informed before posting, these cars have the obd2 connector but are obd1 certified, an interface cable will be required DO NOT USE THE JUMPER TRICK!

[Jrs3800]

First things first... The 94-95 Vans with the 3800's are all OBD1 Compliant, they all used the ALDL 12 Pin OBD1 Connector, but used OBD2 codes..

Second, the Diagnostic Pin to flash codes is not present in the ALDL... 94-95 OBD1 will not flash codes..

[tucsondirect]

Originally Posted by Jrs3800

First things first... The 94-95 Vans with the 3800's are all OBD1 Compliant, they all used the ALDL 12 Pin OBD1 Connector, but used OBD2 codes..

Second, the Diagnostic Pin to flash codes is not present in the ALDL... 94-95 OBD1 will not flash codes..

this is not true i know this because i have a 94 3800 V6 that has an obd2 connector but the pinout is not odb2 cert. The commands to pull info are Obd1 However you may be correct as it may be possible to use some odb2 commmands, i have not tried yet and am in the process of gathering commands to send to the Car

so to sum it up it is OBD1 Cetified Has an obd2 connector, responds to obd1 commands but not all of them and it is possible that it MAY respond to SOME obd2 commands (im not sure as i havent been able to get a connection via an obd2 protocol) the baud rate is 1892

[Jrs3800]

You have a 94 U body van or a 94 C or H Body car?

The 94-95 C and H bodies will have the OBD2 16 pin connector... The only exception may be the very early 94 production...

all of the 3800 C, H and U bodies for 94-95 use the exact same PCM no matter what connector they have.. L27 EPROM is Different from the L36 EPROM and not just in programing..

I am slowly getting away from the 94-95 PCM's as the failure rate was high and almost never a complete failure.. My 95 TS is updated to OBD2 as well we are working on the wiring harness for my 95 Bonneville to convert to OBD2..

I don't think you will be able to get anything to function with the OBD2 commands..

Are you scanning the PCM as a 94-95? Little confused in what you are doing