I thought I'd try a little experiment today and see what speed the cruise control would resume from. Having set it at 75 mph on the highway, I hit traffic that slowed us down to 20 mph. I hit the RES button and the old Jag took off like a bat out of hell - I had to hit the brakes real quick to avoid slamming into the guy in front of me!!

Previous cars I have had wouldn't resume if the difference in speed from the previous setting and current speed were more than 20 mph or so. Maybe I'll try to resume from 10 mph on the way home, just to see where the threshold is

 

lol, close call then?

 

The cruise control will not engage below 16 mph according to my 97 owners manual. It will be interesting to know if the resume works. Note there is a warning to not use resume if the shift lever is manually in 2nd or 3rd gear to avoid over revving.

 

Yes Jim, very close!

 

I tried it on the way home at 10 mph, and it didn't work. I'm still surprised that it resumes with such a large speed differential, but hey, it sure is fun with passengers on board!

 

Interesting, would sport mode make it take off even faster?

 

Cruise engagement overrides Sport mode, in other words, it shifts normally.

I like the cruise, it's much more gentle than a BMW.......The Germans floor the throttle if you're 2 mph below cruise speed.

 

Not from such a low speed but I've been impressed the way resume elegantly attains original speed (when it actually works)

Other cars I've owned are like 'you want to do that,I'll get you there as fast as I can"

 

As Rob mentioned, in Cruise Control mode, the Transmission Control Module overrides Sport Mode and all the other gear shift maps (Traction Mode, Hot Mode, Gradient Mode, etc.), employing a custom Cruise map "to minimize unwanted gearshifts and 'hunting' and is activated when cruising near to the set speed, or resuming."

See page 1272 of the X308 Workshop Manual pdf.

Cheers,

Don

 

Sounds like the wrong time and place to experiment.

 

Had a similar reaction from my mother when I hit the resume button from 50, was set at 70. The old XJR picked up her skirts and sprinted to 70, my mother, who was sat in the front passenger seat, told me I was too old to be a boy racer! When I told her it was the computer and not me she replied " who programed that? Stirling Moss? "
That maybe the reason that I can get better millage with my right foot than I can using cruise. The only time I use cruise now is through the 50MPH average speed check areas at alleged roadworks ( they appear to just be somewhere to store 50,000 traffic cones, and earn money off speeding fines as you never see anyone working on the road ) on the motorways.

 

Your mother knows who Stirling Moss is? Even my wife thinks it's expensive ground covering for the garden!