Hi,

I have an automatic transmission xD 2009, and also a question...

When using the cruise control, is it normal for the set speed to increase as you go downhill even if the slope isn't that steep?

For example, If I set the cruise control at 25mph, even on a low slope it will start to increase up to 35-40mph (I'm assuming with the weight of the car). The cruise control does not turn off on it's own, but it will eventually come back to 25mph once the road gets flatter... unless, of course I brake to help it slow down faster then I have to reset it.

I've only noticed this when setting the cruise control at slower speeds (25-35mph)... I don't recall having this issue when setting it in freeways (at 50-65pmh)

Ever since I got my XD for some reason I thought this was normal... but recently I temporarily exchanged cars with a friend who has a Yaris 2009 with a manual transmission to learn to drive a stick and I immediately noticed that her car doesn't do that (the speed will stay set no matter what).

Now, is it because they're different transmissions? Is it normal, or should I call my dealer and let them know about this?

Please help.

Thanks in advance, btw.

S

 

You may want to check your manual, but some cars have a minimum speed you should be at before you use cruise... it might work below that speed, but maybe not the way it should. This could be part of.

Purely speculation anyway... I haven't checked the xD's manual.

EDIT: Just checked the g/f's xD owner's manual... says the minimum is 25mph.

 

So if the minimum speed 25mph, and is not working at that speed... should I contact my dealer? or is the minimum speed more like a it 'may or may not work' gray area? Is it normal for a scion XD to not work at that speed?

 

because all the cruise control does is maintain throttle input to maintain the speed you set it at. it does not apply brakes whatsoever.

then manual tranmissions and cruise control, the car will use the throttle to speed up the car, but when you're rolling down a slope, the car is still in gear and naturally begins engine braking, which slows the car down, and cruise control will keep it from slowing down too much.

so remember, all cruise control does is apply appropriate throttle input for you to keep from falling under your set speed. it does not do anything to keep you from over shooting it when rolling down a slop by applying brakes or anything.

 

Oh, I get it.... Thank you both for your help and information!!

 

cruise will downshift to try to keep you at 3 MPH over your set, but as stated, it doesn't apply brakes.

 

driving a stick at 25 mph you must be in a lower gear - 3 maybe. Being in that gear would give you more engine braking than an auto in drive.While the auto would coast down hill picking up speed the manual would be slowing you down with engine braking.

 

Minimum cruise control speed is 35mph. That is what it is on most cars. Your car will speed up when going downhill in an automatic unless you downshift into 2nd gear.