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How Does Cruise Control Work?

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73K views 28 replies 19 participants last post by  omodos  
#1 · (Edited)
Not sure if I have a problem on my Cruise Control or do not know how it works?

BMW E46 325i SPORT (2004) Auto

1. I click the I/O symbol on steering wheel (the green speedometer light shows up on my dash)
2. With my foot on the gas, I press the speedometer symbol on steering wheel
3. I take my foot off the gas.
4. Speed drops!

I can increase and decrease speed with +/- THAT WORKS but it doesn't stay at specified speed.

It works occasionally when I keep my finger pressed on the speedometer symbol buttom on steering wheel for a few seconds but not always?

HELP!
 
#2 ·
You have to hold the button for a few seconds. Holding it tells the cruise control you want to record whatever speed you're going at, so when later you drop below that speed (brake, have to turn, whatever), you can just press that same button again and the car will climb back up to the previously set speed.
 
#5 ·
Press I/O tu turn on
When you are at the speed you want, press + to SET.
The speedo button is only for going back to your SET speed.

Eg: Say you cruise at 60MPH. The cruise control will stop (but not turn off) if you tap the brakes (or clutch for manual trannies) or you press the I/O button while cruising. If you want to go back to 60MPH again, you simply press the Speedo Button and the cruise control takes you back to 60.

Hope that clear enough.:thumbsup:
 
#8 ·
press i/o tu turn on
when you are at the speed you want, press + to set.
The speedo button is only for going back to your set speed.

Eg: Say you cruise at 60mph. The cruise control will stop (but not turn off) if you tap the brakes (or clutch for manual trannies) or you press the i/o button while cruising. If you want to go back to 60mph again, you simply press the speedo button and the cruise control takes you back to 60.

Hope that clear enough.:thumbsup:
+1
 
#6 ·
Wow, thank you! I swear it doesn't tell you to press + in the BMW manual. Looking forward to 'cruising' tonight.

It will be quite surreal. My last car was a manual (left foot always busy on the clutch, left hand on the gear lever, right foot on the accelerator, right hand on the wheel) Now my left foot/hand are free and right foot free, right arm on the window, steer with my thighs)

.. until I have to turn or brake that is :eek:)
 
#15 ·
You can't set or resume the cruise control to anything below 20mph, however if you hold the decelerate button it will go slower. I cant remember how slow it will go, but I remember seeing the number 11 mph on my gps.

The cruise control probably goes plenty fast. Autobahn and all.



Pretty much everything newer than E46 had that.
 
#19 · (Edited)
The I/O (really 1 and 0, by the way) enables the Cruise.
The + button sets the speed at whatever speed you are going when you press it. If the system is already active, then this button will increase the speed until you let it go.
The button with the speedo symbol is the resume key, it brings the car back to the set wpeed after using the brakes or the clutch.

You drive along, minding your own business, and decide that the cruise control would be nice, you press the 1/0 button -- binary for on/off -- to turn the system on. Then you attain the desired speed and press the + button. Life is grand, the sun shines and the birds sing.

You need to slow for traffic ahead, so you hit the brakes. The cruise control turns off -- goes to sleep, really -- and you slow to whatever is necessary for the conditions. The conditions resume to the pre-slowing state and you speed up as is appropriate. You realize that all is well with the universe, the sun shines and the birds sing, so you press the button with the speedo symbol on it and tak your foot off of the gas pedal. The car remembers the speed it was previously going, and -- wait for it... -- resumes that speed.

Conversely, you are cruising along with the cruise control set, and the conditions change and you need to be going faster for a few moments, whatever. All you do is press the gas pedal to speed up. Do whatever needs to be done, then release the gas pedal and the car will slow to the speed it was already going. The Cruise is still doing 60, while you overrode it to 70, all you do is let off of the gas and the car will return to 60 without doing anything else.

You can also be cruising along with the Cruise Control actively setting your speed, and press the + button and the car will speed up, just like hitting the gas pedal. The difference here is that when you release the + button, the car will maintain the new speed.

The real question here is, how come this needs to be explained? Can't you figure out what the buttons do while pressing them as you drive?

Two things are always true, you can add speed at any time by pressing the gas pedal, and you can turn the system off -- put it into standby, actually -- by pressing the brake or the clutch. If the system is running, you can over ride the set speed by pressing the gas pedal. The car will return to the set speed when you release the gas pedal unless you use the brake or the clutch. If you use the brake or the clutch, the system will be disabled -- put to sleep, not turned off -- until you press the resume button. The car does not have the ability to push the pedals softly -- it will not resume the set speed casually -- so the resume mode will be full throttle accelleration until the previous speed is reached, and then the throttle will be reduced to maintain that speed.

Press the 1/0 button to turn the system off. The default is for the system to always be off, so if you have it on and set, then park the car the system will be off when you start it again. Some systems will turn off if the speed drops below about 30, but some will retain the previous set speed and allow you to resume as long as you have not actively set the system off by using the 1/0 button. (1 = ON, 0 = OFF)
 
#21 ·
The I/O (really 1 and 0, by the way) enables the Cruise.
... words...)
Great explanation, but missed one feature: The 1/0 button also is a "suspend" for the cruise control much in the way tapping the brakes is. Press it once and the car will coast. Press it a second time (or once while the system is suspended already because you hit the brakes or haven't set a speed yet) and the cruise control turns off. I'm pretty sure the system doesn't go anywhere near full throttle to resume speed though, it's simply far more aggressive than other companies set their cruise control.

A really convenient feature of our system that no other manufacturer's has that I've seen yet (I'm sure some do though) is that each tap of the + or - increases or decreases the speed by 1mph. If you're feeling all legal and are cruising at the speed limit of 65 and the limit increases to 70, just give that + button 5 taps and it'll take you up to 70 and hold there.