Does E53 4.8iS engine brake?
 

Today I was driving on a very hilly road with long strethes up and long stretches downhill. I was going about 45 MPH, the RPMs were at 2000-2200, when I tapped the brakes on the downhill. I did not need to slow down, as 45 MPH is not much of a speed, it was just a habit, to see if the brakes are functional before getting to the buttom of the hill and realizing that there are no brakes...lol...

Anyways, at that point, the RPMs shot up to 4000-4500 and the car visibly slowed dow, the RPMs held steady for a while, while the cars gears changed from "6" to probably "3" or something. The gear selector remained in "D" and nothing else was engaged, no brakes (other than that tap), no gas...

I was able to repeat this phenomenon on a couple more hills

So, am I facing an epic engine/transmission failure or is this some kind unknown to myself feature of the car engine transmission programming?

Thank you

This is what BMW called Adaptive Transmission Control.

so, this is normal??? wow!!! i need to read up on that feature... thank you

here what i found:
Downhill detection

Upshifts are suppressed when driving downhill without pressing the accelerator. If the driver presses the brake pedal, the transmission shifts down by one gear to provide extra assistance. This ensures the braking effect of the engine is utilised more effectively.

Adaptive transmission control

I believe the car is learning the style you drive.
When my daughter drives longer time the X also starts to change gear when I hit the brake downhill. After some time me as the driver that behaviour stops.

Great feature BTW. My Chevrolet Trans Sport always changed into the highest gear when driving down, Very annoying somehow.

Good luck

Helmuth

"Above average braking manoeuvres cause the system to change to the sports gearshift program with earlier downshifts."

Your brake "tap" probably made it think you needed to stop at a much faster rate than the downhill slope. Have a look at the consumption needle when going downhill also :)

He won't find a consumption needle on his 4.8is. ;)

I did not know that. Did they omit it to prevent scaring people?
In that case when I go downhill in my 4.4 the consumption needle shows zero

hahaha, i sure don't have the consumption needle there, they stuck the oil temperature gauge in that place - the instrument cluster is similar to the M cars, where the redline on the tach is illuminated and extinguishes as the engine reaches operational temps (or so they say), and the MPG gauge is swapped for the oil gauge, the lights are more of light orange as opposed to deep orange and the dials have silver rings around them...

a pic from last week's mileage flip to 26K: