I am a large user of my CC . In fact I use it every time I drive whether in the village or town or on the highways. I use it anywhere from 40MPH and up. The other day while driving around I hit a fair size bump and the car jumped out of CC. This is only the second time it happened and considering the condition of various roads I have to assume this bump was greater the the normal pot holes in the area. So for those who use their CC have you had similar experiences and have they been few or greater then normal. By the way neither my Lexus or Chevy pickup have done this .

 

I use mine frequently, never had it fall out of a locked speed. Perhaps the impact jarred the brake pedal slightly?

 

I have never had any of my V8 Jags drop out of CC on rough roads. When they go into limp mode (XK8, XJ8, and XJR) they will drop out but not for rough roads. The XJS's would drop out of CC for no particular reason, but that is just another V12 quirk. My Xterra will drop out of CC when going up a steep hill or over rough roads.

 

It's normal for cars to disable cruise control if there is wheel slippage detected (driving over deep puddles, ice, bump). The differential senses wheel slippage, and has to shut off cruise control.

In some older cars that didn't do this, it was entirely possible for one wheel to just start spinning wildly, while the other (with traction) was going at its normal speed. This caused unpredictable loss of stability.

 

I haven't had the XKR do it, but I've had other cars do it. I always figured it was because the bump was strong enough to make the ECU think there was a collision.

 

I use my CC most of the time when unless the traffic is just too tight. My wife says I drive with my fingers instead of my feet. I wish my XKR had the ACC.

 

I've seen CC drop out with bad enough roads that caused TC (which is in effect braking), with several cars (jag & non-jag) so it seems normal.