Table of ContentsElectronic Transmission ControlSubjectPagePurpose of the System . 4Transmission Versions and Control Systems . 6Transmission Identification . 8System Components . 10Transmission Control Module . 11Speed Sensing . 12Transmission Oil Temp Sensor . 13Kickdown Switch/Circuit . 14Brake Switch . 15Transmission Range Selector Switch . 16Transmission Program Switch . 17Steptronic Components . 18Magnetic Valves . 19Pressure Regulating Solenoids . 20Mechatronics Module . 21Instrument Cluster . 22Transmission Features and Principles of Operation . 24Adaptive Hydraulic Pressure Control .24Downshift Protection. 25Reverse Lockout . 25Engine Warm Up Cycle . 25ASC/DSC Shift Intervention . 25Torque Reduction . 25Emergency Program . 26A/C Compressor Load Sensing . 27Shift Lock . 27Torque Converter Clutch . 28Shift Solenoid Control . 30Pressure Regulation . 31Shift Programs .32Steptronic .34Initial Print Date: 1/15/03Revision Date:

Model: All with BMW Automatic TransmissionProduction: AllObjectives:After completion of this module you will be able to: Identify BMW EH Automatic Transmissions. Identify Electronic Transmission Control Components Understand Electronic Transmission Operation Diagnose Transmission related faults using the DISplus or GT-1 Understand service items and special tools.3Electronic Transmission Control

Purpose of the SystemElectronically controlled transmissions were introduced on BMW products in 1986 on 5 and7 series vehicles. Currently EH (Electro-hydraulic) transmissions are offered on almost everyproduction model (Except E46 M3 and E39 M5). EH transmissions offer the following benefits the to driver: Increased driving safety by reducing fatigue. All shifts are automatic as opposed tomanual transmissions which require more driver interaction. Increased fuel economy through use of lock up torque converter. Increased fuel economy through optimized shift points. Improved shift comfort by use of “Overlap Shift” technology (ZF). More available features through the use of CAN bus technology.4Electronic Transmission Control

The EH Control System is designed to work in conjunction with the engine electronics forprecise shift control. The TCM receives information on engine RPM, load and throttle position to provide optimum shift points to maximize fuel economy and driver comfort.The function of an EGS System is to: Monitor all operating conditions through input signals Continually assess operating conditions by processing input data and select theappropriate operating program for current conditions. Activate transmission system components and to communicate with other drivetraincontrol systems. Respond to driver selected driving program (Economy, Sport or Manual).In addition to providing shift control, the TCM also adapts to changing conditions within thetransmission by monitoring slip ratios and modifying line pressure. This increases the life ofthe transmission and reduces maintenance and adjustments. The TCM controls the operation of the Lock-Up Torque Converter which further increases economy.On current models, the TCM also has the capability of adapting to driver habits andresponds to changing environmental conditions. Items such as rate of throttle input andkickdown requests are monitored to select the most appropriate shift program.The EGS system is also required to maintain occupant safety, safeguard drivetrain damage,improve vehicle emissions and operate in failsafe mode when a malfunction occurs.5Electronic Transmission Control

Transmission Version and Control SystemsEach BMW Electro-hydraulic transmission has a corresponding control system. They aredesignated “GS” which stands for Transmission Control. This acronym is from the Germanwords Getriebe Steurung. Each transmission can have more than one control system, thisdepends upon application (model year, series etc.). Below is a listing of ZF control systemsused on BMW vehicles, Hydramatic control systems are shown on the opposing page.ZF Control SystemsTransmissionBMW ID #Manufacturer Model/YearIDControl System Engine4HP22 (EH)4HP22 (EH)86 535i86 635i86 735iGS 1.2XGS 1.2XGS 1.2XM30M30M304HP24 (EH)4HP24 (EH)88-9/91 750iL (E32)92-94 750iL (E32)90-94 850i/Ci (E31)GS 1.27GS 1.29GS 1.29M70M70M70A5S310Z5HP1893 530i/iT (E34)94 530i/iT (E34)95 M3 (E36)96-99 M3 (E36)GSGSGSGSM60M60S50 (US)S52A5S325Z5HP1900 323i/Ci/CiC (3/00-8/00)01 323iT (from 4/01)GS 8.60GS 8.60M52 TUM52 TU01-02 325i/Ci/CiC from 9/0000-01 330i/Ci/CiC from 6/0001- 525 from 3/0101- 530 from 3/0103 Z4 (E85) 2.5i and S560ZGA6HP26Z5HP245HP30GA6HP26ZGA6HP26Z6Electronic Transmission Control840Ci (E31) from 9/96540i (E39) 1/97-8/97740i/iL (1/97 - 4/97)740i/iL exindexindex50)50)50)60)M62M62M62M6298-03 540i98-01 740i/iL00- X5 4.4iGS 8.60.2 (CAN index 60)GS 8.60.2 (CAN index 60)GS 8.60.2M62, M62 TU 99-02M62, M62 TU 99-01M62TU93-94 740i/iL (E32)93 540i (E34)94-95 540i (E34)94-95 840Ci (E31)95 740i/iL (E38)GS 9.2GS 9.2GS 9.22GS 9.22GS 9.22M60M60M60M60M6095-01 750iL (E38)96-97 740i/iL ( -1/97)96 840Ci (E31)95-97 850CiGS 9.22.1GS 9.22.1GS 9.22.1GS 9.22.1M73/M73TUM62M62M7302- 745Li (E65/E66)03- 760Li (E66)GS 19GS 19N62N73

Hydramatic Control SystemsTransmissionBMW ID #Manufacturer Model/YearID #ControlSystemEngineA4S310R(THM-R1)4L30-E(A4S310R) 90-92 525i (E34)93-95 525i (E34)92 325i,is,ic (E36)93-95325i,is,ic (E36)92-95 318ti (E36)GSGSGSGSGS4. & GS 4.16M50M50 TUM50M50 TUM42A4S270R4L30-E(A4S270R) 96-9896-9896-9896-9896-9897-98328i (is,ic -97)318i (is,ic-97)318ti (E36/5)Z3 1.9 (E36/7)Z3 2.8528i M44M52M52A5S360R (GM5)5L40-E (A5S360R) 99-0099-0099-0099-00323i/Ci (7/98-3/00)328i/Ci (6/98-5/00)528i (E39) 9/99-8/00Z3 (E36/7) 2.3/2.8GS 20GS 20GS 20GS 20M52M52M52M525L40-E (A5S390R) 00-03 X5 3.0i (4/00 - )GS 325iT (8/00-3/01)GS -03 325xi/xiT & 330Xi (- GS 208/00)GS 525i/iT (9/00-3/01)GS 530i (9/00-3/01)GS -02 Z3 2.5/3.0 (6/00- )M54M54M54M54M54M54A5S390R (GM5)TUTUTUTUGS 20 TCM (Siemens)7Electronic Transmission Control

Transmission IdentificationBMW automatic transmission are manufactured by two suppliers for the US market: Zahnradfabrik Friedrichshafen: Commonly referred to as ZF. ZF manufactures bothmanual as well as automatic transmissions. GM Powertrain - Hydramatic: Hydramatic is a manufacturing division of GeneralMotors located in Strasbourg, France. Hydramatic supplies automatic transmissions to BMW for four and six-cylinder vehicles.BMW has developed an internal numbering system for their transmissions for orderingparts, information research and identification. Also, each transmission manufacturer usesan internal identification system. Here is a breakdown of these identification codes:BMW Identification Code BreakdownA5S 440ZA AutomaticS StandardNumber of GearsOverdrive RatioS Top Gear OverdriveD Top Gear Direct DriveMaximum Input Torque Rating in Nm.ManufacturerZ ZFR HydramaticG GetragZF Identification Code Breakdown5HP 24Number of GearsHP Hydraulic Planetary(automatic)ZF Internal DesignationHydramatic Transmissions have internal designations , however they are not used often.The internal code for the A4S310/270R is 4L30-E and the A5S360/390R is 5L40-E.8Electronic Transmission Control

Transmission ID Tag LocationIn order to identify BMW transmissions there are identification tags located externally on thetransmission case. The tag contains information such as Manufacturer, Serial number,transmission type etc. This information is needed when ordering parts, referencing bulletinsand calling for technical assistance. ZF - Tag is Located on 1. Right hand side (passenger side)of transmission case.(5HP30 and 5HP18)2. Left hand side (drivers side) oftransmission case.(6HP26Z, 5HP24 and all 4HP)3. Rear under output shaft. (5HP19)ID Tag Location 5HP19ID Tag Location 5HP24 Typical ZF TagGM - Located on left hand side(drivers side) of transmissioncase.GM ID Tag (GM 5)Hydramatic ID Tag Location (GM5)9Electronic Transmission Control


Transmission Control ModuleThe TCM receives inputs, processes information and actuates the output elements to provide optimal shift points. The TCM is programmed for maximum shift comfort and fueleconomy. The TCM on most BMW vehicles is located in the E-Box next to the ECM (DME).Always refer to the proper ETM for TCM location.There are several types of TCM housings: 35 Pin TCM (TCU) - used on the 4HP transmissions 55 Pin TCM - used on the A4S310R (THM-R1) 88 Pin TCM - used on all others up to 98 134 Pin TCM - used on all BMW transmission from the 99 model year.(Note- the 134 pin TCM was introduced on the 98 Models equipped with theA5S440Z).The 134 Pin TCM is also referred to as SKE (Standard Shell Construction). The SKE housing uses 5 separate connectors. On transmission applications only three connectors 1, 3and 4) are used. Connectors 2 and 5 are blank and are NOT used. The connectors are bluein color to avoid confusion with the ECM (DME) connectors which are black.!34 Pin control modules are supplied by Bosch for ZF transmissions and Siemens forHydramatic transmissions. Bosch and Siemens control modules are NOT interchangeable.134 Pin TCMwith SKE housingConnectors55 Pin TCM1234588 Pin TCM11Electronic Transmission Control

Turbine Speed SensorThe Turbine Speed Sensor is used to provide input (turbine) shaft speed information to theTCM (EGS). The input shaft speed signal is used in conjunction with the output shaft speedsignal to determine gear range and slip time information for processing in the TCM. Not allBMW transmissions use a turbine speed sensor. Some TCM’s use the TD (engine speed)signal to determine input shaft speed. All transmissions with the exception of the A5S325Zuse an inductive type sensor which generates an AC analog signal. The A5S325Z currentlyuses a Hall Effect Turbine Speed Sensor which will send a digital square wave signal to theTCM.4HP22/24 (EH), A4S310/270R: These transmissions do not use a Turbine Speed Sensor.The TD signal is used to determine input shaft speed. The TD signal is an output signal ofthe DME control unit.A5S310Z, A5S325Z, A5S440Z, A5S560Z, A5S360/390R: These transmission use a turbine speed sensor. The TD signal is also used with the turbine speed signal to allow theTCM to monitor Torque Converter Clutch operation. The TCM can control torque converter clutch slippage and also monitor for faults.Output Shaft Speed SensorThe Output Shaft Speed Sensor is used to provide output shaft speed information to theTCM. The output shaft speed signal is used in conjunction with the turbine speed signal toprovide the TCM with information on gear ranges and slip times.All BMW electronic transmissions have an output shaft speed sensor. The output shaftspeed sensor is an inductive type which will generate an AC analog signal to the TCM. Thefrequency and amplitude of the signal will increase as output shaft speed increases. Theexact location of the output shaft speed sensor varies by transmission model.OutputSpeed SignalTypical Speed Sensor SignalTurbine Speed SignalTCMDME12Electronic Transmission ControlGETRIEBESTEUERUNG

Transmission Oil Temp SensorThe TCM is provided with transmission oil temperature informati