MaxxECU online help

BMW DCT related links

•BMW DCT BIG HOWTO. <-- READ this guide, please, just do it before asking questions already covered.

•BMW DCT error codes.

•BMW DCT TCU firmware flashing.

•BMW DCT CAN protocol.

•BMW INPA diagnostic tool.

•DCT clutch relearn.

•DCT hardware identifier

•DCT hardware upgrade.

•BMW installation and wiring.

•DCT shifter emulation.

•DCT Realtime Data description.

•DCT shifting options.

•MTune - DCT Control.

•MTune - DCT Settings.

 

 

Note: It is recommended to have this protocol on a single bus, because of the high message load.

 

 

GEN1 DCT in a BMW E9x vehicle

The GEN1 DCT gearbox control can be wired to a BMW E9x, but ONLY if all CAN messages are available on the vehicle, that is needed, ONLY BMW E9x.

 

GEN1 DCT in a non BMW E9x vehicle <-- The recommended way

When setup as the above, all CAN messages needed to make the TCU happy, is transmitted, do not use this setting on a BMW E9x vehicle, since it will interfere with current messages on the bus from vehicle.

 

 

Required BMW E9x (GEN1) hardware

Note: any E9x DCT gearbox will most likely work, with their respective gear selector and buttons, but we will only support the E9x M3 version with our DCT harness for now.

Make sure the TCU firmware is correct for the connected accessories (shifter, buttons etc).

 

Required M4 (GEN2) hardware

 

Required inputs.

 

 

 

 

Additional input

•DCT clutchkick/burnout mode input. <-- Experimental usage (only for testing) <-- does not seem to work cause of some internal TCU limitation.

 

 

Available settings/functions.

•User table with custom torque value (Nm) to customize shift smoothness and also controlling the actual clutch pressures.

•Shiftcut, read about available DCT shifting options.

•Throttle blip Blip delay.

•Time after launch torque control.

•End gear ratio correction feature (but preferable change in the TCU firmware).

•Clutch slip engine cut feature to protect clutches in case of a slip event.

•Built-in warnings for up and down max shifting times.

 

 

Changelog

MTune 1.151

•0x332 message fix, to send correct revlimit floor and ceiling values.

 

MTune 1.150

•GEN1: Added brake pressure input to be transmitted, if available.

•GEN1: Added CAN forwarding of DCT messages between buses if GEN1 DCT control and BMW E9x (MSS60) not on the same bus.

 

MTune 1.149

•GEN1/GEN2 DCT: Internal filter for the transmitted torque values added.

•GEN1/GEN2 DCT: Internal filter for engine RPM optimized.

•GEN1/GEN2 DCT: Internal filter for wheel speed optimized.

•GEN1/GEN2 DCT: New DCT Setting added to limit transmitted torque (min/max), some GEN1 TCUs (M3) firmware does not like getting above 800Nm and sends the gearbox into N.

•GEN1/GEN2 DCT: Added parameter for the negative torque before reaching burnout RPM.

•GEN1/GEN2 DCT: Added clutchslip mode during launch.

•GEN1/GEN2 DCT: Added parameter/table for the positive torque during the actual burnout + option to move over to regular torque table.

•GEN2 DCT: Shift strategy change during up/down shifts for smoother operations.

•GEN1 DCT: Shift strategy change, min reported pedal position on gear 1.

 

MTune 1.148

•GEN2: Paddle signals ( Transmission UP shift and Transmission DOWN shift) can now be used with OE shifter.

•GEN1/GEN2: When control is activated, RealTime data value GEARBOX_OIL_TEMP and TRANSMISSION_TEMP is also updated from the TCU OIL TEMP.

•GEN1/GEN2: clutchkick update, internal timer added to try to kick the clutch better.

•GEN1: Fixed a bug where DCT torque was fixed during reverse (shift status was stuck).

•GEN1: Fixed a bug where blip was randomly activated on the reverse gear.

•GEN1: Fixed an issue where the reported pedal position during launch and BETA strategy was not fixed (used the table value).

 

MTune 1.147

•GEN2: Fixed a bug where the actual rev limiter was transmitted wrongly (overflow).

•GEN2: Front and rear wheels was mixed in transmission.

•GEN2: A detection of the xHP app, will not stop CAN communication.

 

MTune 1.146

•BETA support for the BMW M4 (GEN2) gearbox.

•GEN1 now uses the actual idle rpm target on outgoing CAN data (might improve the clutch relearn procedure).

•GEN1: Added a new improved shifting strategy.

•GEN1: DCT reported pedal angle table.

 

MTune 1.145

•New MTune button to reset TCU adaptations.

•Option to read OBD TCU data like clutch pressure, line pressure.

•Now transmits real rev limiter values in auto mode, and max in manual mode.

•Min/max allowed up/down shift warnings can now be disabled by entering "0".

•Internal speed filter added.

 

MTune 1.143

•DCT shifter emulation mode added including new digital input functions: DCT drivelogic UP and DCT drivelogic DOWN and DCT Mode Switch.

•Increased the maximum RPM for up shifting, should now be possible to shift up to 9000rpm.

•Fixed a bug which could cause NEUTRAL engagement over 8400rpm.

•Fixed a bug which could cause the slip cut protection not to work.

•Fixed a bug where a drivelogic mode change on some gearboxes was not captured in RT-data.

 

MTune 1.142

•Fixed a bug related to second gear ratio calculation (clutch slip).

•Fixed a bug where the DCT clutchkick/burnout mode input was constantly checked for vehicle speed to determine a burn mode or clutch kick mode when activated.

•Fixed a bug where random shiftcut events were missed.

 

MTune 1.140

•Recalculated driveshaft RPM.

•No error code on long upshifts from R to 1.

 

MTune 1.131

•Fixed a bug in where shift status was not correct when in Reverse gear.

 

MTune 1.129

•New Speed gear ratio correction setting added.

•Improved TCU speed Source (DYNO mode) to be able to shift without a speed sensor on the dyno.

•New blip delay function added.

•Adjusted internal torque calculation model.

•Adjusted torque calculation model during downshift, to try to easy up the downshift tuning.

•New and updated DCT Realtime Data values.

•Fixed a bug where some customer experienced disengage of clutches at higher gears and no pedal engagement, change of behavior to try to keep the current gear engaged.

•Fixed a bug which disengage clutch in Reverse gear.

•Fixed a bug where the CF18 DCT error code was present all the time.

•Fixed a bug which disengage clutch in Reverse gear.

 

MTune 1.128

•Initial suppoort for BMW DCT E9x (GEN1).

 

 

Not working/issues/TODO/Limitations

•Stock BMW DCT RPM shiftpoints for now (no auto set points in MaxxECU). Auto mode will work to drive the vehicle moderately, manual mode is to be used for more racing oriented driving.

•BMW M3 (GEN1) TCU is internally limited to ~15.5bar clutch pressure. If you intend to push 800Nm+, see: DCT hardware upgrade and BMW DCT TCU firmware flashing.

•DCT clutch relearn/adaption must be done using BMW INPA diagnostic tool or other OBD tool capable of doing these functions without stock ECM present.

 

Note: if you get weird shift operations or fault codes, please check and make sure there is no collisions on the bus you are using!