How do you pull codes from a 89 Renix

Okay, I have a dummy light in my xj 89 Renix, auto setup, and I can not figure out what my problem is. The check engine light is on, and it starts hard.. You have to feather the throttle during start up and for about 30 seconds after it 'starts' to get it to idle on its own. I tried cleaning all my electrical conectors but to no avail... How do you pull the trouble codes on these? Or what scanner do I need to read the real time data... And to make things better the local jeep dealer cant order me a FSM... ohy.. The idel seems to be odd as well.. once it runs under its own power it is running rich, which leads me to the coolant sensor...then the idle creeps up on me... which makes me think maybe map or IAC... any input?

Also check the TPS......they can cause all kinds of havoc!

When I plug in my Snap On scanner on my 87, it says no codes available. I am thinking the Renix system does not store codes in a way that can be easily read out, I can only get real time data, but I get all the inputs like IAT, MAP,TPS, O2 sensor and heater, open/closed loop, etc.
There is a Jeep/AMC scanner called out in the Renix FSM that supposedly can read them. It is called the DRB II.
Most of the sensors can be tested with a standard digital volt meter IAW the Renix FSM.
There is a company that handles most of the FSMs for all the dealers, but the name escapes me now...

Interesting did not know there was a tester for the Renix.

Start testing sensors would be your best and cheapest best. Light can come on just due to a little emission box under your steering wheel. Basically it is a timer box.

Evertrhing I have read says that Renix can't store codes. PM Ecomike or 5-90 they will know how to get that light off and if the codes are stored.

Most likely is your IAC is gummed up. Take it out, being careful of the "O" ring. Clean out the seat in the TB and clean up the piston stopper. Regular old spray oil works as good as anything else, for cleaning things up. Let a few drops of oil run down behind the piston/stopper, don't try to move the piston. I use a few drops of synthetic motor oil, seems to work out well. After a week or so put a few more drops back there. Repeat twice a year or so.
Pull out the MAT sensor and clean off the end with a toothbrush and some spray oil, careful it can be damaged.
Let us know how this works out and we can try something less likely if most of the trouble doesn't clear up.
I'm not a big fan of dumping stuff down the throttle body, as all that crap goes down through intake valves, into the cylinders and back out the exhaust valves, if your lucky. Iy your not lucky it can gum up a valve seats.

what dummy light and what check engine light?

is it the maintenance required light that is on? if so, that has nothing to do with your proplems. thats just a timer for the o2 sensor. it goes on after approx. 82,500 miles

renix doesnt store codes but the snapon 2500 can give you realtime data.

i would test the tps and cps, actually i would test all the sensors. if you go here, http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm if you are not familiar with the testing procedures