OBD2 Scanners

[MarkN]

Question about scan tools:

 

I realize our Reattas are much better than other cars of the era at diagnostic capabilities, but having an OBD2 scanner already, I was wondering if it can be used to “talk” to my ‘91? I know and adapter cable is needed, but has anyone tried this?

[2seater]

Probably not a definitive answer, but I have a Auto X-ray 35000 from circa 2005 that does both. It has several adapter cables as the connection is different. It does have some difficulty connecting to my 90 via the ALDL as it must shut off some of the dash to avoid interference but it does work. It cannot read anything the onboard diagnostics can’t but it does have a very limited recording capability so you can do a little review after an event. Slow, maybe one frame per second, but it is a tiny advantage. The one big issue with the slow frame rate is the data in each frame are not synched very well 

[Ronnie]

I didn't think OBD2 scanners would interface with any of the Reattas. Is the '91 an exception?

[Padgett]

No. Reatta (and GM from 1981 to 1994) use an  "Assembly Line Data Link" (ALDL) which is NOT OBD-II. Moates.net has what you need. For a hand held I like the OTC 2000 with a '93 Pathfinder cart. There is other stuff if you want to reprogram ( see http://www.tunercat.com ) but for all scanner operations the indash scanner in both Reattas and Allantes is just as good and can clear codes.

[RLTherio]

I have an old OTC 4000E in my collection of tools with the Pathfinder 97 cartridge. I am curious as to which is better, the OTC 4000 or the Reatta's on board diagnostic?

[Padgett]

Key is does the 4000 have the ALDL cable ? Suspect diagnostics are the same.

[Ronnie]

Can the OTC scanners read BCM codes? If not Reatta diagnostics is better.

[Padgett]

My OTC 2000 can read/clear/override everything the CRT can. For ABS it just says what wires to jumper.

Edited July 11, 2021 by Padgett

[MarkN]

Ronnie:

 

I don’t believe the 91’s are unique. As said above, the ALDL is not OBD2 but adapter cables can be bought for less than $20.

 

IIRC, the OBD1 GM reader merely connects two of the ALDL pins together, which initiates the flashing CEL sequences, if any. You could do the same thing with a simple jumper wire, but you have to know which pins to connect, of course.

[Ronnie]

10 hours ago, MarkN said:

I don’t believe the 91’s are unique. As said above, the ALDL is not OBD2 but adapter cables can be bought for less than $20.

Are you saying you can buy a cable to adapt an OBDII scanner to a Reatta ALDL?

[RLTherio]

Also in my collection of vintage tools is this GM ECM and ABS code reader. It's pretty much an expensive paper clip. Set the switch to "H" and count the flashes.

Edited July 12, 2021 by RLTherio

[Padgett]

I connect A to G (88) or A to H (89-91) and sound flashes for ABS only. Everything else I read on the display. Is described in the Factory Service Manual under "Computer Diagnostics" (section 8D).

 

For DIY hardware see moates.net under GM 1985-1995 an ALDL to USB adapter & cables is more like $80 and then you need software e.g. TunerPro RT ($40) More if you want to do your own programming. This is from my '93 GTP with DOHC-6.

[Ronnie]

1 hour ago, RLTherio said:

Also in my collection of vintage tools is this GM ECM and ABS code reader. It's pretty much an expensive paper clip. Set the switch to "H" and count the flashes.

Have you used it on your Reatta? It would be handy to check codes if the CRT ('88-'89) or the IPC went out on later models.

[RLTherio]

The 1990 that I am planning to buy is still at the used car dealer. It had a camshaft sensor error and the last update is they are replacing the ECM.

I knew about checking the codes while I test drove it and they agreed to fix it before I take it.

Edited July 12, 2021 by RLTherio

[Ronnie]

13 minutes ago, RLTherio said:

The 1990 that I am planning to buy is still at the used car dealer. It had a camshaft sensor error and the last update is they are replacing the ECM.

I knew about checking the codes while I test drove it and they agreed to fix it before I take it.

Could be the ECM but odds are this is the problem.

[MarkN]

22 hours ago, Ronnie said:

Are you saying you can buy a cable to adapt an OBDII scanner to a Reatta ALDL?

Amazon has an adapter cable from OBD 1 to 2, but not sure how it works. Thus, my start of this thread.

[Padgett]

Doesn't matter. GM ALDL scanners (and cables) are specific to that protocol and nothing else. If interested see ALDLSTUFF.ZIP. Ronnie, want me to send you a copy ?

 

 

OBD-II connector

 

 

ALDL Connector

 

ps "Uploaded Images - To insert images into post click the + sign." What + sign ? Have to click "insert".

 

 

 

[Ronnie]

1 hour ago, Padgett said:

If interested see ALDLSTUFF.ZIP. Ronnie, want me to send you a copy ?...

 

 ...ps "Uploaded Images - To insert images into post click the + sign." What + sign ? Have to click "insert".

Sure. I'd like to take a look at it.

 

The + sign was on the thumbnail for inserting photos into a post. Plus sign must have disappeared during an update to the forum software. I've changed the language file to say clicking the thumbnail is all that's needed to insert into your post.

 

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