Chrysler Repair: 96 Jeep: code 19 ais circuit. What does it mean?, grand cherokee jeep, air flow rate

Question
Please explain what a code 19 - ais motor circuit is. I own a 1996 grand cherokee jeep with tramission problems. The reader stated a code 19

Answer
Hi Tova,
I am wondering about the code 19 readout because the ais is an engine actuator not a transmission component. Are you certain that the transmission controller was not queried by the code reader? If not, then a code 19 is actually  different for that controller entirely. In the Chrysler cars the trans controller code 19 means that there is a problem of communication between the trans controller and the engine controller which is handled by the "CCD data bus". That could be due to a problem in either controller or a problem with the wires. I would seek a more thorough readout with a Chrysler/Jeep readout unit for clarification and possible further delineation of what exactly is wrong in that communication. In light of there being transmission problems I would suspect the ais circuit is not involved at all. But if it were were is what it is about:
The automatic idle speed motor is a device on the throttle body that open or closes the by-pass air passageway so as to modify the idle speed. It consists of two coils of wire that cause the pintel that changes the air flow rate to move either in or out. The engine controller applies voltage to the coils and expects the rpm to change. I suspect that either one of the two coils is "open" or that the pintel is sticking due to crud build up as those might well be the reasons it would see a fault. You will find a 4 wire connector at the motor where typincally the outer pins are for one coil and the inner pins are the other coil. You could check the resistance of the two coils which should be similar. And if those are measureable (neither 0 nor infinite ohms) and similar, then I would remove the motor and clean its tip and the by-pass air passage which it controls. Finally it is possible that there is a break in one of the four wires between the controller and the plug-in. Unfortunately I don't specialize in Jeeps so I don't have the wiring diagrams to tell you which pin at the motor goes to which pin at the controller. But check the coil continuity and the motion of the pintel and clean the passageway. Then disconnect the battery for a few minutes which should erase the 19 code, and then drive if for a while and see if the 19 code returns or not.
But the first order of business is to find out which controller gave out the 19 code.
Roland