Operation CHARM: Car repair manuals for everyone.
Home >> BMW >> 2006 >> 325i Sedan (E90) L6-3.0L (N52) >> Repair and Diagnosis >> Transmission and Drivetrain >> Automatic Transmission/Transaxle >> Description and Operation >> Part 1

Part 1




24 01 03 (040)
6-speed automatic transmission
E53, E60, E61, E63, E64, E65, E66, E70, E81, E83, E85, E86, E87, E90, E91, E92, E93





Introduction
The 6-speed automatic transmissions were jointly developed by BMW and ZF (Zahnradfabrik Friedrichshafen).
> - E53, E83, E85, E86 [system overview ...]
> - E60, E61, E63, E64 before 09/2005 [system overview ...]
> - E60, E61 from 09/2005 until 03/2007 and



E63, E64 from 09/2005 until 09/2007 [system overview ...]
> - E60, E61 from 03/2007
[system overview ...]
> - E60, E61 from 06/2007 with sport automatic transmission and
E63, E64 from 09/2007 with sport automatic transmission [system overview ...]
> - E65, E66 [system overview ...]
> - E70 [system overview ...]
> - E81, E87, E90, E91, E92, E93 [system overview ...]
Depending on the model concerned, the automatic transmission is either standard or special equipment (option 205).
> - E60, E61 from 06/2007
From 06/2007, besides option 205 "Automatic transmission", option 2TB "Sport automatic transmission" is also available.
The special equipment "Sport automatic transmission" includes, amongst other features, gearshift paddles and a SPORT button.
> - E63, E64 from 09/2007
Option 205 "Automatic transmission" is discontinued.
On E63, E64 vehicles, only option 2TB "Sport automatic transmission" is available. Depending on the model concerned, the "sport automatic transmission" is either standard or special equipment.
The sport automatic transmission differs from the automatic transmission as follows:
- Gearshift paddles on steering wheel
- SPORT button in the selector lever trim
- Sport program also possible in selector lever position "D"
- Separate gear selector switch (GWS)
So as to be compatible with the engines with higher torques, the automatic transmissions are designed with different strengths. The automatic transmissions thus differ, e.g. through different torque converters.
Depending on the engine fitted, the following 6-speed automatic transmissions are fitted:
- GA6HP19Z (designed for maximum torque of 400 Nm)
- GA6HP19Z TU (designed for maximum torque of 400 Nm)
- GA6HP26Z (designed for maximum torque of 600 Nm)
- GA6HP26Z TU (designed for maximum torque of 650 Nm)
- GA6HP32Z (designed for maximum torque of 750 Nm)
(technical updates, e.g. of transmissions, are indicated with the letters "TU".)
The automatic transmission requires 5 multi-plate clutches to shift between the 6 gears: 3 input clutches and 2 brake clutches.
[system overview ...]

Electric steering lock discontinued:
On vehicles with automatic transmission, the electric steering lock is discontinued as follows:
- E90, E91, E92, E93 from 12/2006 (US version only)
- E60, E61 from 03/2007
- E63, E64 from 09/2007
- E70 from start of series production

Brief description of components
The automatic transmission consists of the following components:
- Mechatronics module
The automatic transmission is controlled by the mechatronics module. The mechatronics module is a combination of hydraulic unit and electronics module.
The hydraulic control unit is the hydraulic part of the transmission control system.
The electronics module contains the EGS control unit, the sensors and the electrical connections within the transmission. (EGS is the abbreviation for electronic transmission control)

- Selector lever, selector lever position display
> E53, E81, E83, E85, E86, E87, E90, E91, E92, E93
> E60, E61 until 03/2007
> E63, E64 until 09/2007
The selector lever has the following positions:
P - for Park
R - for Reverse
N - for Neutral
D - for Drive (= automatic mode)
M/S - M for manual mode = Steptronic, S for sport program = automatic mode with sporty map
The selector lever position display is located in the selector lever trim.

> E65, E66
The selector lever is located on the steering column.
The selector lever has the following positions:
P - for Park
R - for Reverse
N - for Neutral
D - for Drive (= automatic mode)
The selector lever position display is located in the instrument cluster.
- GWS: Gear selector switch
> E60, E61 from 03/2007
> E63, E64 from 09/2007
> E70
The gear selector switch is configured as a control unit in its own right. With the gear selector switch, the transmission is no longer actuated mechanically, but rather electronically.

- SPORT button for Dynamic Driving Control
> E60, E61, E63, E64 with sport automatic transmission
Dynamic Driving Control (FDC) is activated with the SPORT button: Gearshift times are shortened and the shift characteristics are made more sporty. The engine responds more spontaneously to movements of the accelerator pedal. The steering and holding forces of the steering tuned for a sportier feel - for Servotronic or active front steering (AFS). AFS includes Servotronic.
> E70
On the E70 with the option "Adaptive Drive", only the damping characteristics are changed (normal or sport).
- Steering wheel with buttons for sport program and manual mode
> E65, E66
The steering wheel has a button for selecting the program. The following drive programs can be selected in a predefined sequence: Sport program, manual mode or automatic mode.
The steering wheel also houses the buttons for changing up and down in manual mode.
Program selection and control in manual mode are described in the Owner's Handbook.
- Gearshift paddles
Vehicles with gearshift paddles:
In addition to the sequential gear selection with the selector lever, the gears can also be selected using the 2 gearshift paddles on the steering wheel.
The shift pulse is transmitted electrically to the EGS control unit. With this gearshift method ("shift-by-wire") there is no mechanical linkage between the gearshift paddles and the transmission.
Pull one of the gearshift paddles briefly to change up a gear.
Press one of the gearshift paddles briefly to change down a gear.
- Instrument cluster display
The drive ranges and drive program are displayed in the instrument cluster, the signal required for this is sent from the electronic transmission control.
- CID: Central Information Display
> E60, E61, E63, E64, E70, E81, E85, E86, E87, E90, E91, E92, E93
The CID displays detailed information about the Check-Control messages in the instrument cluster.
The instrument cluster controls these messages on the K-CAN (body CAN).
In addition to the visual display, the Check Control also alerts the driver with acoustic signals. Depending on the importance of the associated message, a single or double gong with varying volume and tone will sound. The instrument cluster controls these warnings by means of the K-CAN. Acoustic warnings are emitted by the M-ASK (multi-audio system controller) or CCC (Car Communication Computer).
- CD: Control display
> E65, E66
The control display is the central display for the information and communication system.
The control display is used as an interface between the MOST and K-CAN data buses. (MOST = "Media Oriented System Transport"; K-CAN = body controller area network".)
Amongst other things, detailed information about the Check-Control messages in the instrument cluster are displayed on the control display.
The instrument cluster controls these messages on the K-CAN (body CAN).
The electronic transmission control requires signals from the following components (in alphabetical order):
- Brake light switch
The signal from the brake light switch is needed for the function of the selector lever lock and the adaptive transmission control.
- DME or DDE: Digital engine electronics or digital diesel electronics
The DME or DDE sends messages about the current operating status of the engine to the EGS (e.g. engine speed or torque).
The EGS reports the current operating status of the transmission back to the DME or DDE.
- DSC: Dynamic Stability Control
The DSC optimises both driving stability when pulling away or accelerating and traction. Within the limitations of the laws of physics, DSC compensates for driving conditions such as over/understeering. As part of this process, dynamic driving signals (e.g. wheel rotation speed, lateral acceleration) are sent to the DSC control unit. DSC transmits the processed signals regarding cornering, acceleration and winter detection to the EGS control unit.
- Accelerator pedal module
The signal from the accelerator pedal module is needed for the adaptive transmission control.
- JBE: Junction box electronics
> E70, E81, E87, E90, E91, E92, E93
The JBE is the data interface (= gateway) between the K-CAN and the PT-CAN. Signals from the F-CAN are simply looped through. (K-CAN = body CAN; PT-CAN = powertrain CAN; F-CAN = chassis CAN.)
The junction box consists of the JBE and the power distributor.
The power distributor provides power, amongst other things, for the gate pattern diagram and the EGS control unit.
- KGM: Body gateway module
> E60, E61, E63, E64 from 09/2005
From 09/2005, the vehicle electrical system has been modified. The body gateway module (KGM) supersedes the SGM.
The KGM is the data interface (= gateway) between the K-CAN and the PT-CAN. (K-CAN = body CAN; PT-CAN = powertrain CAN.) The diagnosis wire is connected to the KGM.
- SGM: Safety and gateway module
> E60, E61, E63, E64 up to 09/2005
> E65, E66
The SGM is the data interface (= gateway) between the K-CAN, byteflight and the PT-CAN. (K-CAN = body CAN; PT-CAN = powertrain CAN.) The diagnosis wire is connected to the SGM.

Continued in Part 2
pro multis · About Operation CHARM