My Cruise Control is OUT OF CONTROL!!!

Hello all, first time post here. I've looked on the site for this issue with no luck, so hopefully you can help me out.

My XJ is a 00' auto, 4.0, with about 150K miles. I tried to use my CC the other day (for the first time in a couple of years) and my Jeep went full throttle!! It wouldn't hold its speed, it kept accelerating. I turned CC off but it continued to accelerate. I turned the engine off, then back on, and it revved to redline.

I ended up disconnecting the CC cable from the throttle body, and the problem went away. I don't have any vacuum leaks (that I know of), no CELs, and the Jeep runs great other than that.

Any ideas? I'm leaning towards the CC module/servo, but would like to hear your opinions before I spend nearly $100 for a new part.

Thanks.

The CC module is vacuum operated. Vacuum leaks cause the engine to rev. I would start looking at the vacuum system for hose and hose fitting for damage, failed check valves, and leakage. If you really think the CC module needs replacing, I would try a junkyard part.

Thanks Tim, I'll look into vacuum leaks. I just left the throttle cable disconnected for now.

Did you make any progress, more than anything, sounds like one or both of the servo solenoids are stuck. The speed should not do anything until the CC is "on" and the "set" button is engaged. Once that happens the PCM tells the Vacuum sol to open and the Vent solenoid to close, and cycles the Vacuum sol on and off until enough vacuum is drawn to reach desired speed. Then the PCM closes the Vacuum sol and cycles the Vent sol to maintain speed.

I would check the plug to the servo, make sure the contacts are clean. If its not the contacts, get a servo from a yard(as Tim suggested), got mine from a yard for only $30, only three small screws to get it out.

Maybe check to see if the cable is stuck in the unit? pull on it a little and see if it frees itself. Might just need some lube.

I had a similar thing happen to me. Except mine was a plastic spring holder next to my throttle body that broke. The spring holds no tension and I've yet to find a correct name for it or a replacement part.