Howdy!

I tried this search once before and came up with a paperclip -- but I've yet to ask about it on the forums and am guessing someone can give me a reality check here.

Today I watched two old gm service videos on youtube. One was about transmission diagnostics and the other was about driveability diagnostics.

I started to think about how sweet it would be to have a scanner. After some searching, I saw two things that seem like they could work to provide a lot of good information -- or at least significantly more than my handy paperclip.

Do y'all know about the Snap On MT2500 and if it would help with diagnostics on a 1990 LeSabre? There is cartridge for domestic vehicles (including GM "thru 1999") associated with the MT2500. Would this tool also return information for trans solenoids and such?

The other thing that I saw, which doesn't seem to be widely available is the Expertec Tech I Scanner.

Thanks for your help/advice here!

Luke Skywalker before he see'* the diagnostics video:

transmission diagnostics video:

I am not familiar with the use of 2 way scanners, however I believe the only portion of the transmission the ECM can control on the 1990 MY is the TCC solenoid. I believe there are switches that indicate to the ECM what gear it'* in, but it wasn't controlling it until the 4T-60E, which started in later model years.

How about one way scanners for the 1990 that returns more info than the paperclip, info such as idle rate and other "live data" from the motor sensors?

If a scanner will read OBD 1 live data, it should be able to pull it. I expect the mentioned Snap-On should be able to do it to with the proper modules.

I use an Actron CP9145, coupled with the ALDL cable, and it works great for me. I can scan live data, read codes, and even handle the nightmare of OBD1.5. OBD2 can get a little funky on it, but I rarely use it for that.

It really depends on what the issue is, but it'* a great tool to help diagnose.

I am just not sure what you can do with a 2 way on OBD 1, vs just the standard scanner, or even if you can command anything but live data.

Thank you.

As far as I can tell, I've only three pins A,B,and M on the 12 port ALDL. Not sure if this info is helpful here, I believe it was referenced in the maintenance manual...I'll have to double check it.

Have you used the actron scanners on pre 1991 cars?

It seems like there was no true standard for the 1990s and maybe it is kinda hit or miss with the scan tools. I've searched a couple of boards -- going way back and I can't seem to find anything definitive.

Yeah, unlikely to get any info from the trans -- In the video below, at 5:40/5:45 the mechanic introduces a slide rule ...

I used my actron on the 1990 Olds 88 I had for a pit, and I could read data on it just fine.

Thank you.
For the CP9145, am I correct in saying that I'll need an additional part, which is the 12pin to 16pin adapter? I've ordered the scanner already...

You will need kit CP9127 which includes the cable and power feed.

Thank you so much for your help. I'll let you know how it goes.