Looking for a scan tool that will read GM's "OBD 1.5"

Canadian Poncho · A Poncho Legend!

Looking for a scan tool that will read GM's "OBD 1.5"

Greaser · Canadian Poncho Superstar!

I used to read codes for my 1994 Suburban using the method this guy uses.

Accessing GM Codes.

https://www.troublecodes.net/gm/

https://buickforums.com/forums/threads/1994-buick-park-avenue-ultra-obd-1-5.21407/

JUN 10, 2011

#6

dcraig1000

Full Member

1) early 95's are usually a 12 pin configuration located under the steering wheel inside the car, if so you can stick a paperclip in holes A and B which when looking straight(from drivers position) at the 12 hole pin is the top right one and the next to top right.

2) 16 pin configuration is a paperclip in the 4 and 5th hole to get the flash codes

3) 16pin requiring the same code II as a 1996 car or later would require, this would be a late model 95 and the code II along with the computor brain should be under the hood.

all 3 of these scenarios are only possible on the 94's and once you figure out which one is yours the codes are easy to read, you will receive series of flashes from your check engine light the first series is the first number the second series of flashes is the second number.....ie 6 flashes then 4 flashes, would be error code 64

Canadian Poncho · A Poncho Legend!

That's how I've read codes on my truck. Here is the apparent pinout for my car:

You'll notice pin 4 and 5 are both grounds so shorting a paperclip there won't work. I spent a ton of time online trying to find a way to pull codes on this car without a scanner and the consensus is you can't.

timbuk · Canadian Poncho Superstar!

Looking for a scan tool that will read GM's

DonSSDD · Canadian Poncho Superstar!

Todd, can you get that same schematic for a 1993? Maybe then have some hint of what 4 and 5 pin were there and follow the same process on the 94?

DonSSDD · Canadian Poncho Superstar!

History of obd in wiki covers obd 1.5, says you need a scan tool.

en.m.wikipedia.org/wiki/On-board_diagnostics

DonSSDD · Canadian Poncho Superstar!

mechanics.stackexchange.com/questions/18245/live-scan-tool-for-obd-1-5-gm-transitional

Canadian Poncho · A Poncho Legend!

I read that link a couple of days ago. That Actron CP9145 is no longer available so I contacted Actron asking if they had a current model that works with OBD 1.5. They replied and said their 9690 is compatable. It's about $225 USD and according to Amazon reviews it's not a great scanner and often breaks.
I dropped it off for inspection last night and left a note asking the shop to try to scan it.

Canadian Poncho · A Poncho Legend!

Shop called- unable to scan. I suspected that would be the case. On the bright side it breezed through the safety inspection.

timbuk · Canadian Poncho Superstar!

if the check engine light is on u could check the usual culprits.... cat, tps, o2 hope for the best

Canadian Poncho · A Poncho Legend!

Yes. I'm also looking for a shop manual for this car.

Prefectca · Poncho Master!

I remember scanning those cars. If I remember correctly we used an old Snap-on mt2500 scanner

4SPEED427 · A Poncho Legend!

On those ones I can't recall if it clears the code when you unhook the battery for a minute. Have you tried that?

Canadian Poncho · A Poncho Legend!

I haven't yet. I just picked up the car from the shop. Safety inspection, oil change and wheel balance (I felt a slight vibration at 90kmh) all in for $96! Gotta love the local shop. As a bonus he loaned me his old Snap On Scanner. I think it's the MT2500 (I just tossed it in the trunk as we were in a hurry). It's the one in the briefcase with a bunch of cables and "keys". He said if it works for me he'd sell it to me cheap. He didn't have time to play around with it on my car and just tried his modern scanner. I'll be buying it either way as it will work on my 94 Chevy anyway.

4SPEED427 · A Poncho Legend!

I see a whole lot of "bonus" in your post!

JC2+2 · Poncho Master!

RE: Looking for a scan tool that will read GM's "OBD 1.5"

Canadian Poncho · A Poncho Legend!

Looking for a scan tool that will read GM's

Prefectca · Poncho Master!

Its been a long time since I used an mt2500 but the keys you mentioned should be for obd 2. Your car would need the correct GM cartridge and cable to fit the old style GM diagnostic connector.
Also I seem to remember that those era cars had problems with the mass airflow sensor. If the codes are cleared the car would stumble when first started, the check engine light would come on and then run fairly well, but with a drop in fuel economy and higher emissions.

Paul

DonSSDD · Canadian Poncho Superstar!

RE: Looking for a scan tool that will read GM's "OBD 1.5"

Canadian Poncho · A Poncho Legend!

Looking for a scan tool that will read GM's

Canadian Poncho · A Poncho Legend!

This Snap On scan tool did the trick. It came with the proper "key" for the plug. It had an OBD1 325 ESC failure code. This could mean a number of things but the number one choice was faulty MAF. I threw caution to the wind and ordered one up. Should be here Wednesday. I'm definitely buying this scan tool. Lots of great features for an oldie.

4SPEED427 · A Poncho Legend!

Shoot, I should have told you to tap the MAF with a screwdriver handle! I just remembered now that the guys could often find a bad one by doing that. It would stumble when tapped if it was bad.

Prefectca · Poncho Master!

RE: Looking for a scan tool that will read GM's "OBD 1.5"

4SPEED427 · A Poncho Legend!

Looking for a scan tool that will read GM's

Canadian Poncho · A Poncho Legend!

It's a consistent problem. Idle hunts a bit and she hesitates when pulling away. When I cleared the code the light returned right away.