Quote:
Originally Posted by Jeffatpm
I read the transmission relearn algorithm process - turn the key to on and press the gas pedal all the way to hold the kick down switch for 25 seconds. Does the car make any noise and something to register it has changed over?
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This is a false rumor that has persisted across many BMW forums for years...but indeed is false and is just an example of something started by someone that didn't understand BMW technology that has been around since the 1994 model year when Adaptive Transmission Control (ATC) debuted.
In a nut-shell...it doesn't work (long term) as others mentioned because you're not really doing any "reset" or "clearing" of the transmission control module (TCM).
All it takes is a simple understanding of BMW's ATC (adaptive transmission control) and it all becomes clear. First, driver influenced adaptations (AGS) are NEVER stored in the TCM...they start new at every start up...this is WHY the tranny is adaptive for EVERY driver at EVERY start up.
The adaptive nature of ATC's driver influence...takes data from the position of the accelerator pedal and how fast/slow the pedal is pushed. Upon this data...the TCM will select one of 3 predetermined shift patterns:
- extreme economy (granny-toe) mode
- economy (normal) mode
- sport (adaptive sport mode is slightly less aggressive than the manually selected EXTREME sport mode)
The process that the rumored reset has you go thru is a waste of time and implies that you've done something special...when all you've done by turning the ignition on, pressing the accelerator pedal to the floor and holding it there for a few seconds, then starting the car...is tell ATC that you are driving aggressively....thus the adaptive sport mode (#3 above) is selected. You could have done the same thing by just starting the car and driving aggressively (which for some is an everyday occurence).
Again, that is why the setting never remains...because you haven't actually done a reset...you've just pretended to be an aggressive driver, thus ATC selects the adaptive sport mode...then when the ignition is turned off...nothing is stored because driver influenced adaptations are NEVER stored. The next time the car is started...it will take data anew dependent on if the driver is a granny, normal driver, or aggressive...and the appropriate driving mode will be selected.
You can see the text in the red box below explains that driver influenced adaptations are NOT stored: