ALDL connector?

Tiny
YASIRDAHHAM
  • MEMBER
  • 1995 PONTIAC GRAND AM
  • 2.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 240,000 MILES
I have an OBD 1 connector as a DLC for my car. It has only 3 wires (namely; A, B and M according to the terms used with this connector). No scanner could establish a communication with the PCM of my car via this connector, not even the simple connection of A and B was any useful. It looks like the data line is terminated somewhere inside the dashboard cavity or as it reaches the PCM itself if not a whole PCM is faulty, any idea where does these 3 wires go? I conducted a continuity test for two of these wires according to an advice that I received here on this website, the continuity test was positive, yet none of these wires has any voltage at all.
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Tuesday, August 3rd, 2021 AT 1:01 PM

59 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon,

The reason you cannot communicate is due to 1995 was a transition between OBD 1 and OBD 2.

You need a scan tool that reads OBD1 but has a cable that will communicate with the L terminal.

I had a snap-on scanner with the needed cable for communicating.

You need to call around to shops and see if anyone has that tool to read the system. The dealer most likely will not help as it is too old for them.

Roy
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Tuesday, August 3rd, 2021 AT 2:23 PM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
As Roy stated you have what many call unofficially an OBD 1.5 car. GM had a few of them in between 95 and early 96. The connector looks like an OBDI part but the system actually uses a hybrid of OBD I and II parts and protocols. They also used the OBD II connector the same way on a couple models. The common OBD II units won't read the data because it's in the wrong place and the wrong type and there is no jumper method to read the codes like the OBD I systems. The Snap-On MT2500 (Brick) with the correct cartridge will read them, as will the Tech II and the Tech 2000. The OTC Genisys will as well. Some dealers will have them setting on the shelf under 2 inches of dust while others will just wave you away. It depends on when they became GM dealerships and if the tool still works.
I would call around or if you wish to DIY look online for the above scan tools, the bricks and older Genisys units are all over the place, just be sure they have the software or the cartridge for your year. OH and while many of the new lower priced OBD II units claim to work with OBD I and have the adapters, very few actually work with the system you have.
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Tuesday, August 3rd, 2021 AT 3:43 PM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
Steve W : Sad news for someone as remote from the states as in Iraq! But I am very grateful to you for the important info that did hit me for the first time.
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Wednesday, August 4th, 2021 AT 12:19 AM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
ASEMASTER6371: Thank you dear Roy for the invaluable info, you guys are more than great.
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Wednesday, August 4th, 2021 AT 12:25 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You are welcome.

Always glad to help.

Roy
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Wednesday, August 4th, 2021 AT 2:26 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
If you use Ebay you can usually find them on there.
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Wednesday, August 4th, 2021 AT 8:10 AM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
Thank you dear Steve, I haven't been to Ebay but for this cause I will, even if through a friend who has a credit card, things are pretty primitive here with payment, no PayPal and no trusted bank to use a credit card but once I am in Istanbul mid August I will check from there because I have an account in their governmental bank.
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Wednesday, August 4th, 2021 AT 2:04 PM
Tiny
STEVE W.
  • MECHANIC
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Here are a couple of eBay item numbers to give you an idea of the type of scanner that would work. MT2500 - 334099128547 Genisys - 133831212299 or 164862732215
I have one of each. The Genisys is a bit easier to use as it uses built in software and no cartridges.
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Wednesday, August 4th, 2021 AT 2:25 PM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
Is this a good choice for this case of mine (from Ebay) https://www.ebay.com/itm/164886660950?hash=item266402c756:g:p MAAOSwK Fgr-OM ? The price is suitable as I can see: OTC Genisys Scanner for parts, Includes Cables, Manuals, Case - SPX Scan System
Popular Item 1 viewed per hour
Condition:For parts or not working
Price:US $120.00
P.S, it is the screenshot that is intended, the first attachment might refer to another model other than what I am inquiring about
Also: I didn't see any referring to OBD 1 on the Ebay page nor any mentioning of Pontiac. I count on your extensive skill here for the OBD 1 part , as for the (Pontiac) term missing here, is it this part included there that allows connecting the scanner to my DLC : Chrysler Cable (212635

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Wednesday, August 4th, 2021 AT 2:53 PM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
That is the type of scanner, however you need the cable to connect to the early GM units. The software in them covers OBDI - OBD 1.5 and OBD II as long as you have the correct cable. The correct connector is in the image attached OTC 212653. Then there is the adapter harness that goes between the tool and the cable OTC 3305-72, that is used with all the cables with the round connection on them. That is the second image. You can still buy those cables new.
Look around on there and see what you can find. There are usually a few of them for sale as people decide they don't need them anymore. They are not super fast but they work and if you visit their site at OTC you can still get most of the parts and cables.
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Wednesday, August 4th, 2021 AT 5:08 PM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
This is great! A friend of mine living in the states sent this stuff to me, any idea or comparison between this and that? I am in need of some scanner that doesn't has what you called as cartridge yet it is ready to deal with my engine (no provision of having a software to download for Pontiac): https://www.otctools.com/products/obd-i-code-scanner-gm-0?fbclid=IwAR0sE1l2nAr2Fd06_9LBJRbzzH3rpfK87fTr_gnfJVMEm3r94EEMJDkNERI
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Thursday, August 5th, 2021 AT 12:51 AM
Tiny
ASEMASTER6371
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Check the description. It looks like 84 and 95 will not work with this code reader.

Roy
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Thursday, August 5th, 2021 AT 2:38 AM
Tiny
STEVE W.
  • MECHANIC
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I don't believe it will work on your 95 because of the odd computer in your vehicle. Those generally worked with the earlier system where you could simply short out two pins to make the check engine light flash the codes. That ability doesn't exist on your car.
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Thursday, August 5th, 2021 AT 3:21 AM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
Then I would better stick to the OTC Genisys unit you recommended? Seems like my friend in the states needs too much of your knowledge dear Steve.
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Thursday, August 5th, 2021 AT 4:37 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
I would opt for a tool that will work on your vehicle. In this case it's difficult due to the system used. Unlike the earlier OBD I cars where a simple paper clip jumper would cause the light to flash, or the true OBD II vehicles where even the cheapest plug in code reader will work the ones in between like yours require a real scan tool to read and display the data. It makes it harder for the do it yourself folks to work on them because of that. Instead of a free clip or a $20.00 plug in tool you need a tool that is much more expensive and does far more than most people ever use. The up side is that because it is a true scan tool it has a lot more in it than just reading the codes and can show you testing data and much more.

The scan tools I mentioned both will work on your car. There are a couple others as well but those are not as easy to find as the Snap On and the Genisys units are.
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Thursday, August 5th, 2021 AT 5:38 AM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
A great friend (American just like you) is now contacting the seller to see if it ships to Iraq, otherwise he will arrange for another destination to ship to in Istanbul where I will be available next month. I have no words to repay your help dear Steve.
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Thursday, August 5th, 2021 AT 3:55 PM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
Get used to the tool and you might find yourself helping out others with US cars over there. I have a friend in the Ukraine that does that, he is one of the "go to" guys if you have a US import there.
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Thursday, August 5th, 2021 AT 5:48 PM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
You are most right.
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Friday, August 6th, 2021 AT 3:25 AM
Tiny
YASIRDAHHAM
  • MEMBER
  • 186 POSTS
Dear Sirs who had helped me with this issue (Roy - ASEMASTER6371, Steve and Colby): What do (VIN M) and ( VIN D) in the DLC diagram you sent earlier to me refer to? And is the Energy Reserve Module that is missing from my car( only that dangling 3-wire connector is there inside the dashboard mass- 2nd attachment here) a crucial part for the DLC connector to work or is it just about the Airbag only, i.E. Something that is not essential for the DLC-scanner communication to be there? This is because the Genesys scanner is supposed to be shipped to me in a few days time and I want to make sure that the missing Energy Reserve Module won't prohibit using the scanner, with due thanks to you and to Steve and Colby.
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Friday, August 6th, 2021 AT 4:59 AM
Tiny
ASEMASTER6371
  • MECHANIC
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The M and D refer to the 8th digit in the VIN number identifying what engine would be in your car.

I attached the chart identifying the engine according to the letters.

Roy
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Friday, August 6th, 2021 AT 5:07 AM

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