SEC1939

Interesting feature of E class cruise control. Press decel on cruise lever and car will brake fairly agressively down to about 25 mph. Wonder if this a unique function of the E class with SBC unit?

vettdvr

Don't know if it is unique. I found in mountains it accelerates going up hill and brakes going down to maintain speed w/in about +/- 2 mph.

I turn it off as I don't want to brake going down unless the speed begins to build then I prefer to downshift.

Using power to climb and brake on going down seems inefficient to me.

SEC1939

Agree on the hill decent. I have not tried any other car to see if this same thing happens. It is a nice feature

rsmith7

My 2007 E350 appears to apply the brakes when holding the cruise stick down for deceleration. On my 2002 C230, it does not do this *** aggressively as the E350.

I believe my 350 does not have SBC brakes.

infantry

i use this if i spot a cop, as for him not to see my brake lights to see that "im slowing down"

it uses engine braking basically giving less fuel to the motor and that brings your rpm's down.

so i spot the cop ill hammer on the decel stick and i slow it down to under 73 and no brake lights to basically help him saying, yea i was speeding, until i seen you!

Diesel Benz

Is your car a face lift 211? My understanding is that the face lift is using brakes for CC purposes when necessary but the pre-facelift would not do (even if the car with SBC brakes could easily do it).

If you slow down by reducing gears only, the brake lights would not light up. If you brake with CC on a facelift, at some point it would use brakes and then the brake lights light up even if you are not pressing the brake pedal (but you can feel the brake pedal moving on a facelift car).

Even on a pre-facelift the engine braking is quite strong (may depend on th engine too), can feel like the car was using brakes.

Polar Bear

My 2005 E320 applies the brakes and illuminates the brake lights, as does the W209 CLK without SBC.

vettdvr

??????? Does it use engine braking or wheel brakes going down hill. I notice it doesn't increase more than 2 mph and in the rockeys I would suspect more than engine braking is needed.

Diesel Benz

That was interesting, quite opposite to what I've read so far. The previous info must have been incorrect, a 2005 anyway must be a pre-facelift model.

SEC1939

My 2005 CDI brakes going down hill. Not an engine brake as teh RPM's do not seem to change. Not sure about the brake lights going on ? I do not think they would light since this a cruise control decel.

jkv11503

If it's just a gradual deceleration using the engine braking or wind resistance, 1 or 2 MPH for instance, the brakes will not be used and, therefore, the brake lights will not illuminate.

However, if the deceleration is more severe and requires automatic activation of the brakes, the brake lights will illuminate.

I recently noticed this little fact while driving on a very dark mountain road with my cruise control set. As I began my decent down the mountain the cruise control applied the brakes to maintain my set speed. Because it was so dark outside I could look at my driver's side mirror and see my brake lights illuminate the roadway each time the brakes were applied.

I was quite surprised because I, too, had thought that the brake lights were not used in conjunction with the cruise control. I decided to test it one step further by using the cruise control stick on my steering column to reduce my cruise control setting by 10 MPH at once. Sure enough, the brakes were applied and the brake lights came on.

So, if you're using your cruise control to slow down from 85 to 70 thinking that the cop won't see your brake lights, you might be in for a surprise.

SEC1939

Very interesting discovery. Wonder if other makes do this? I'll try it in the x5 nexttime out

chokaay

I'm pretty sure it's ILLEGAL for car manufacturers to allow their cars to brake WITHOUT lighting up the brake lights. Imagine how easy it would be to get rear-ended by using CC to brake from 90 to 65 in a few seconds when you're begin tailed by a car going the same speed! I'd imagine from a safety standpoint, brake lights are required to illuminate anytime the car's brakes are used.

lkchris

It does light the brake lights and it is NOT a function of SBC.

Don't know about W211 newer than our 2006, but our 2007 GL has a cruise control lever with 1 mph change and 5 mph change detents, and it's really easy to drop 10 mph in a hurry with just a couple taps. It's actually not exactly 5 mph unless you're currently running on a 0 or 5 speed, i.e. it drops or increases to the next 5 or 0 speed. That is, for example, it's 75 to 70 or 73 to 70 and same going up. You can obviously "preplan" how many taps it is to get back to the speed limit. (!)

Basa

I think it is across for all/most cars.

I have tried this w/ Nissan Quest minivans, seems the same approach.
With Toyota RAV4 also the same.

But in general - any car, if driving on steep grade (both up or down) for any length of time *steadily going up/down* more than 10 seconds it is better to temporarily override the cruise with pedal(s). Otherwise puts way too much pressure on the engine. This is in part b/c The cruise does not sense the up/down hill as quickly as your eye sees it, and reacts to it "late". In doing so, it tries to cut of too much gas & air, or supply too much specially in its initial reaction.

leovince2011

i have a problem with my cruise controll in my 270 cdi w209 2004 year.
it's not working. everything its work, the komand its ok. but the comand dont go in engine.