How do you retrieve computer codes from an OBD-I 1990 Cherokee?

There was such a thing as OBD-I scanners. Back in the days before OBD-II, they came with separate software for each car make, and of course, separate cables because they all used different terminals. Not sure if they still make them. Some high end OBD-II scanners can read them if you buy the adapter cables too. As far as Autozone, from what I've heard, they only do OBD-II vehicles.

If all you want to do is read the codes, there is one alternative that might work on your Jeep. Thexton still apparently makes a tool that has an LED light built into it, that you can use if you don't have a check engine light. I found an example of it here, just like the one I bought about 25 years ago;

http://www.metroblaze.com/store/index.php?c=2&n=15...

I'm not familiar with the seller, but at least you know what to look for this way, and also, like I said, I'm not sure if it will work with your Jeep, which might depend on which system you have.Could be a Chrysler setup, or could be a Renault sourced system called Renix.

I did find a pic of where the data link connector for 1990 Jeeps are supposed to be, which is where you would need to plug this tool in;

http://repairguide.autozone.com/znetrgs/repair_gui...

I used to work on some Renault Alliances way back in the day. They actually sold a pretty fair number of them. They had a different setup for probing the computer. 2 little rectangular boxes with pins, with a sawtooth pattern in between them. If you have those, then the Thexton tool won't work on that.

But one thing that all these OBD-I vehicles had in common, is you could also use an analog voltmeter to read them, if you know which terminals to probe.

Actually you can use a scanner with obd1 you just need the proper attachment (some of the better scanners have multiple attachments). I believe most were vehicle specific so it's going to be a pain to find someone with the proper attachment. I'm not sure if pepboys or autozone will have a scanner with the obd1 cable but that's the first place you can try. Otherwise you may have to find a mechanic that does work on older cars of your make (or the dealership).

autozone does free scans but wont concern themselves with obd 1 ,

only obd 2. locate the diagnostic plug, it will require a jumper wire like Gm and Ford you will need a haynes maunal to tell you what terminals to jump.

Turn the key on then off then on 3 times,leaving it on the third time.

The codes will flash through the check engine light.

I had asked the same question 4 times, and haven't gotten a good answer

i take mine to auto zone they check the codes for free and tell you what the codes are for...