WHICH CODE READER?

What type of code reader do I need for my 88 laredo? it is the 4.0 litre model whith automatic transmission. thankyou for your help

I don't think there's any consumer level code reader that will work with the pre-91 Renix system. It uses a serial output while running and does not store codes at all. There have been readers made for the expensive diagnostic systems sold by Snapon and the like, and Jeep dealers used to have a reader, but as far as I know, unless you're willing to shuck out some very big bucks for a professional rig, or unless you luck into an ex-dealership reader, you're out of luck.

5-90 keeps hoping to hack the Renix system to get the serial output, but I don't think he's cracked it yet.

Thank you Mattew, I appreciate your help. I have fixed the jeep for now, but it was the trial and error method. But it worked. have a good new year.
Olaf K.