Cruise control subtle surging

Project Mangler · #1 10-26-2009, 12:55 PM

I have an 09 Clubman (non S), 6-speed with 600 miles on it. Last night I used the cruise control for the first time, and I noticed a very subtle, rhythmic surging while the CC was on. It's as if the car is alternately accelerating and decelerating every few seconds to maintain the set speed. It's very subtle, I don't think my wife noticed it, it doesn't register on the speedo or tach, but I can definitely feel it. This was on a pretty flat highway.

I own other cars with cruise and have never noticed this before, so I don't think it's me. And it only happens when the cruise is on, when my foot is controlling the speed all is normal.

Any ideas? I've searched the forums and found some threads that might be related, but seems to be very rare. And I'd rather not drive two hours to the dealer just for this.

Robin Casady · #2 10-26-2009, 02:03 PM

Turn on the digital speedometer on the tach and see if it registers a speed change.

What speed and rpm was this at? Does it happen at just one speed setting, or a range of speeds?

Have you tried it on other roads? You want to make sure it is isn't responding to subtle ups and downs in the road, or variations in the wind.

Project Mangler · #3 10-26-2009, 02:32 PM

Digital speedo was on, and it was definitely not a response to road conditions, it was a very constant, rhythmic accel/decel. It felt like it was gently accelerating, then cutting off just before it reached the next mph, then repeating the process. I was doing between 60 and 70, speed didn't affect it. I've used cruise on the same stretch of highway in other cars.

remip50 · #4 10-26-2009, 06:37 PM

I felt that in my 08 S too but I thought it was in my head. I'm happy to know that i'm not crazy. It's probably designed this way but i never bothered to ask my dealer.

Project Mangler · #5 10-27-2009, 05:30 PM

Quote:

Originally Posted by remip50

I felt that in my 08 S too but I thought it was in my head. I'm happy to know that i'm not crazy. It's probably designed this way but i never bothered to ask my dealer.

I found a poster in an old thread who said his stopped doing this after he used the cruise a dozen or so times. Has yours got better?