How to reset BMW Steptronic?
Once again, reading the forums stumbled upon a tempo about the reset of the gearshift control adaptation. Today I decided to try it.
Instructions copied below, while writing about the results:
After resetting the first meters the car flew (although it touched a little to the gas), immediately stopped feeling the shifting, as if in the box 1 transmission instead of 5) Also, it was inconspicuous inclusion of the rear speed, there was a small push earlier, but now the car does not move, such same story and with the inclusion of D.
He also noticed the difference in the economizer values, compared the readings at the same speed and with the same engine speed, so here, before the adaptation, the economizer showed 10.5 liters, after 9 liters.
After reading the reviews on the forums of others who did the adaptation, everyone is equally delighted with the result.
There are a couple of comments with the statement that it is better not to adapt it. This will lead to an earlier death of the gearshift control, but this has not been confirmed by the facts.
So this article I do not call anyone to make a dump of adaptation, this is a personal matter for everyone, as they say at their own peril and risk).
How do I reset the BMW automatic transmission control module to factory settings?
Did you know that the automatic gearbox (automatic transmission) on BMW cars will eventually adapt to your driving style? If you drive by the principle of “pedal to the floor,” it will eventually become faster to switch gears up and down. And if your BMW moves smoothly around the city, the box will help you maintain this style.
What if I want to feel the car the way it was on the assembly line?
Hadn’t special coding/programming tools like CGDI BMW programmer?
Read in this manual how to reset the adaptation of the automatic transmission of BMW to the factory settings.
Difficulty level: Easy
Turn the ignition off.
Turns on the ignition, but do not start the engine.
All sensors and instruments must turn on.
If you run the key — turn it to the end without pressing the brake pedal.
(If you have the START / STOP button, press the START button once).
Press the accelerator pedal all the way to the floor (to hit Kick-down)
Keep the pedal depressed for at least 30 seconds.
Release the pedal.
Start the engine.
This procedure has reset the BMW automatic transmission to factory settings.
Now the gear box will re-adapt to your driving style.
Tips and Warnings:
* Be careful — after this reset, the behavior of the automatic gearbox is close to “sporty”
* If you bought a used BMW, better make this reset — the car will adjust to your driving style.
* In BMW, the automatic transmission can be reset every day.
-And if there are jerks at starting, this reset will help?
-The reset must help.
Usually jerks or smooth touching arise for those who prefer a dynamic style of riding. The box adapts to you, and when starting it feels that you are now a “start-up”.
After the reset, the automatic transmission will not have this “memory” and it will behave more naturally.
If it did not help, the service.
For cars with a mileage more than 150 thousand km. the reset of the adaptive values may result in an emergency breakdown of the automatic transmission.
Adaptive values are variable variables that are designed to correct work with the wear of transmission parts. For example, if the sensor indicates that the oil pressure in the automatic transmission has become below the permissible value, then the “box” itself adjusts the operating mode so that the pressure corresponds to the tolerances. After each correction, new data is written to the “brain” and with each new launch, new values of adaptive quantities are used.
Resetting the adaptive values is used only after repairing the automatic transmission or in case the automatic transmission is not working correctly. One of the reasons can really be the failure of adaptive values. Although often the problem lies in physical defects or damage to the transmission.
That’s what WDS says:
The adaptive gearbox control system selects the gear depending on the driver’s driving style and the driving situation at the moment.
The main arguments for using the adaptive control system of the gearbox are:
-Reduction of fuel consumption in a calm manner of driving
-Reduction of gear shift frequency
-Increase traffic safety on slippery roads
-Reduction of the number of necessary interventions in the management of the driver
The ECU applies pulses to the high and low gear shifts to the hydraulic gearbox control unit (solenoid valves, pressure regulator) and determines whether the torque converter lock-up clutch must be connected based on comfort and safety requirements. For this purpose, in a special computer program, it processes input values such as the crankshaft speed, the output shaft speed, the turbine speed, the injection signal, the throttle position (accelerator pedal position), the Kick-Down mode switch, the mode program movement, the position of the control lever of the automatic transmission and the temperature of the oil in the bath.
Place of installation of the computer — the control electronics compartment in the engine compartment.
Driver type evaluation
The following are the factors that are of decisive importance when dividing drivers into types. The result of evaluating the type of driver affects the choice of the gearshift program.
Estimation of the manner of dispersal
The acceleration pattern (forced or more relaxed) affects the selection of the gearshift program.
Estimate of sharp acceleration
After a quiet, economical program of the driving mode, when the accelerator pedal is pressed hard (sudden acceleration), the sports program of the gear shift is automatically called up, oriented to use the maximum engine power reserve. As a rule, this leads to a downshift.
Estimation of traffic conditions
When driving with a constant accelerator pedal position, an economical gearshift program is selected after a while and shifting to an increased gear occurs.
Estimation of the maximum acceleration mode
When the Kick-Down mode is activated, a sports program is immediately called up. After the Kick-Down mode is switched off, the sports shift program remains for a while.
Evaluation of inhibition
Excessive pressure on the brake pedal causes a shift to the sports program and, thus, to earlier shifts to a lower gear.
Selection of the switching program
In addition to evaluating the type of driver for selecting one of the four gearshift programs, there are other functions. These programs are divided by the degree of growth from very comfortable and economical to very sporty.
Program selection key
With this key, the driver can intervene in the selection of programs. When you select the program S (sports), the sports program of the gear shift is switched on and used immediately. You can turn it off only by selecting program A (adaptive) after which adaptive functions are activated again. Program A is the starting position after each launch.
Recognition of movement in the mountain / traffic with a trailer
When driving on a steep slope or when the vehicle is heavily loaded, a gearshift program is called to focus on the full use of the engine’s power reserve. This prevents the pendulum switching.
Recognition of winter conditions
If even with a slight acceleration the driving wheels slip, a winter gearshift program is called up. At the same time, starting from the place takes place on the 2nd gear, and switching to higher gears occurs earlier than usual. In assessing this situation, sensors of the anti-lock system (ABS) are involved. Winter conditions are recognized by the difference between the angular velocities of the front and rear wheels. The winter program turns off automatically, as soon as the system receives a signal that the car has already been travelling for a few seconds on the road with a normal clutch coefficient with a sufficient driving torque.
In addition to the automatic transmission selection in accordance with the above-mentioned criteria for selecting a gearshift program, four special functions are involved in recognizing specific driving conditions.
Motion Detection Downhill
When driving downhill without pressing the accelerator pedal, switching to higher gear is not realized. If the driver presses the brake pedal, in addition to this, a reduced gear is engaged. Accordingly, in this case, it is additionally better to use engine braking.
Rapid deceleration detection
With a sudden drop of gas, the system prevents switching to increased gear. Due to this, in this situation (the rapid transition of the foot from the accelerator pedal to the brake pedal), the engine braking effect is best used. With the sporty manner of driving, the shift frequency due to this function is greatly reduced.
Recognition of the “Stop and Go” mode
In this situation, the reverse switching to the 1st gear is not performed. The car automatically starts in the 2nd gear. This increases the comfort of driving, reduces fuel consumption and reduces the likelihood of rolling away a stationary car. If the accelerator pedal is depressed more strongly, in order to use the full capacity, a downshift can occur.
Through the various interfaces of the AGS, the AGS receives the following information from the following nodes:
frequency of rotation of the output shaft, turbine speed, oil temperature in the gearbox
program selection key
Choice of the program by the driver
control lever for automatic transmission
gear selection, gearshift limit
enabling Kick-Down mode
Depressing the brake pedal
crankshaft speed, engine temperature, throttle opening angle
cruise control system GR
information on movement at a constant speed or on acceleration and braking
ABS / ASC
current wheel angular velocities
Through the outputs of the AGS control unit, the following nodes receive the following information:
Activation of solenoid valves and electronic pressure regulators
The instrument cluster control unit
current program of the driving mode, position of the automatic transmission control lever, if necessary. The message “Emergency control mode of the gearbox” is displayed on the text display of the instrument cluster.
Upon the request of the system for maintaining the set speed (GR) in the AGS, the system switches to a special program of the transmission for the movement at a given speed. This CAT program ensures the full use of the available engine power reserve in this mode. At the same time, however, the number of frequent, successive switching of neighboring transmissions decreases to a minimum. The time delay allows avoiding sudden switching.
Information between the GRU control unit and the transmission control unit is transmitted via the serial interface. About 25 bauds of information are transmitted over a single-wire line.
The gearshift program takes into account the following driving modes:
constant speed motion
emphasized comfort, i.e. with an insignificant level of speed
calculation for maximum tractive effort
calculation for maximum tractive effort
evasion from switching to higher gear to achieve optimal deceleration parameters
evasion from switching to higher gear to achieve optimal deceleration parameters
Instrument cluster interface
From the AGS ECU to the ECU (IKE) there is a serial data transmission line, through which the transmission control unit sends information to the ECU of the instrument cluster on the position of the control lever, the active program of the driving mode A – adaptive or S -sport) and, if necessary, the message “Emergency mode of management of a transmission”.
Kick-Down Mode Switch
The AGS control unit receives a signal to activate the Kick-Down mode via the wire and through the switch to ground. The switch must be adjusted in such a way that it is possible to move with a fully open throttle, i.e. when the accelerator pedal position is 100%, and only when the pedal is pressed even more, the Kick-Down mode is activated.
The switch of the lever of management gearshift control
The AGS ECU detects the position of the automatic transmission control lever via the gearbox switch. This switch converts the current position of the control lever to the code. This lever code is transmitted over four wires (L1-L4) to the AGS control unit.
Position of the control lever of automatic transmission
L1 to L4 (0 = open, 1 = battery voltage)
L1 = 1, L2 = 1, L3 = 0, L4 = 1
L1 = 1, L2 = 0, L3 = 0, L4 = 0
L1 = 1, L2 = 1, L3 = 1, L4 = 0
L1 = 0, L2 = 0, L3 = 1, L4 = 0
L1 = 0, L2 = 0, L3 = 0, L4 = 1
L1 = 0, L2 = 0, L3 = 1, L4 = 1
L1 = 1, L2 = 0, L3 = 1, L4 = 1
The CAN (Controller Area Network) bus is a bus system in which all connected stations are equal, i.e. each control unit can send and receive signals. Simply put, connected control units can “communicate” with each other and exchange information via wires.
Due to the linear structure of the network, if one computer fails for the remaining control units, access to the bus system is completely preserved. The connection consists of two data transmission wires (CAN_L and CAN_H), shielded from interference by a screen (CAN_S).
Currently, this system connects AGS, ASC / DSC (only M62), and a digital electronic engine management system (DME) to each other. In the future, it is planned to connect other ECUs to it. The ECU of the AGS, ASC / DSC and DME systems communicate via the CAN bus with the following signals:
accelerator pedal position
Engine crankshaft speed
motion mode program
intervention in the engine
angular wheel speeds (M62 only)
Connected devices must have the same CAN level. The CAN level can be checked via the diagnostic interface. On the identification page of the corresponding control unit connected to the CAN bus, the CAN level (CAN index) is output.
The gauge of temperature of oil in a check point
The oil temperature in the gearbox is determined by a thermistor, soldered into the transmission harness. Depending on the temperature of the oil in the gearbox, the torque converter lock-up clutch is also interconnected.
Angular wheel speeds
The ASC / ABS control unit receives from ABS sensors, processes and transmits four wheel angular velocity signals. The signal frequency gives the AGS system control unit information about the angular speeds of the wheels. Evaluation of information makes it possible to recognize the passage of turns or winter traffic conditions.
With the program selector on the E38 series, two driving programs can be selected.
Motion mode program
Principle of operation
A = adaptive
The adaptive gearbox control system automatically selects the most optimal of the four existing switching programs. Each time the AGS ECU is started, the AGS program includes an adaptive program.
S = sportswear
When you manually select this program, the system directly switches to the long-term use of only the sports program.
Adaptive control system for switching over the field of characteristics
When driving with a trailer or over a mountainous area, the computer evaluates the change in the acceleration parameters of the car. For this mode, the ECU selects (adapts) a suitable switching program to avoid pendulum switching.
Control of the clutch of the converter lock-up
The torque converter lock-up clutch is activated depending on the position of the accelerator pedal, the speed of the output shaft of the gearbox, the program of the driving mode, the oil temperature in the gearbox, and the gear engaged (only on IV and V gear).
Adaptive pressure control system
An adaptive pressure control system improves the smoothness of the gear shift while driving. When switching to overdrive, adhesion time values are measured, which are then compared to the setpoint range. The averaged deviation value is stored. If the programmed limit value is exceeded, the pressure increases or decreases step by step (0.1 bar). Due to this, the deviations of the engine operation parameters are corrected, the difference in the thickness of the friction linings is compensated and the height adjustment is made.
Manual shifting system in automatic transmission (steptronic)
With the help of the steptronic system, you can manually operate the automatic transmission. The driver’s command is transmitted to the AGS AGU through three switches (per weight) in the manual channel: When the control lever is moved from the automatic channel to the manual channel, the “manual channel” switch is closed. By pressing the control lever in the forward or backward direction, the contacts “switching to increased” or “switching to reduced” are additionally closed.
After installing the new AGS, if contact 15 is ON, press the lever once in the direction of “downshift” or “shift to high” so that the computer recognizes the installed manual step change gear system.
Locking of switching from P / N (Shift-Lock on cars in Japan and the USA version until 09/1996, starting from 09 1996 — for all export versions)
Switching from positions “P” or “N” to “running” positions is possible only after signal processing:
Brake (brake light switch or brake light switch)
Engine crankshaft speed
The control lever of the automatic transmission is blocked if the signal of the brake system is not recognized on a stationary vehicle with the engine running. To be able to “swing” the car (eg, in winter), the inclusion occurs with a time delay of 0.5 seconds. The brake light switch is made in the form of a 12 V short-circuit, and the brake-light check switch is in the form of a contactor for the ground. To lock the automatic transmission control lever, an elevating solenoid is used at the control lever switch
If, in verifying the signals for plausibility, and wiring connections — for absence of short-circuits or breaks, the computer recognizes the presence of a malfunction, it logs messages about it in the fault memory. Switching to a reduced gear at high speed is not realized. At speeds above 8 km / h, the safety interlock prevents the reverse gear from being hydraulically engaged.
If the gearbox control unit fails or if errors that could lead to critical situations (eg unacceptable downshifting) occur, a mechanical emergency program is activated, i. The gearbox control unit is switched off and the fault indication is activated. With each new start, the entire safety system is self-diagnosed.
With the emergency control program, the car remains on the move with some restrictions (IV gear). Depending on the nature of the problem, various backup programs can be used.