Bus messages, TCM

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Bus messages, TCM

For further information on the bus, see System overview, bus and diagnostic communication, petrol

TCM uses the following information:

Information	Unit	From	Description
Engine torque	Nm	Trionic	Current airmass/combustion is converted to torque, unit Nm
Pedal position	%	Trionic	The engine control module uses the highest requested value for airmass/combustion either from pedal position or from cruise control. The value is converted to the corresponding pedal position, unit %.
Kick-Down	ON/OFF	Trionic	When voltage from pedal potentiometer 1 corresponds to the kick-down position (less than 1.50 V), Kick-down ON is sent.
Engine speed	rpm	Trionic	Current engine speed, unit RPM The value is also used to compare engine speed with the speed of the input shaft when Lock-up is activated.
Brake lights	ON/OFF	TWICE	Brake lights, unit ON/OFF.
ENGINE JERK	ON/OFF	Trionic	If T7 detects a misfire, a message is sent on the bus and used by TCM, which then adapts to more favourable shift timing.
Reduced engine output	ON/OFF	Trionic	Driving at high altitudes (approx. 2400 m above sea level, pressure approx. 80 kPa) results in reduced engine output. TCM then uses a special shift programme that allows the engine to reach higher engine speeds than normal.

TCM sends the following information:

Information	Values	Used by	Description
Max. permissible torque	Nm	Trionic	TCM sends max. permissible torque, unit Nm. This value is used in airmass regulation for torque limitation.
SPORT	ON/OFF	Trionic, MIU	TCM sends sport mode, unit ON/OFF. This value is used in airmass regulation to correct the pedal position conversion to the requested airmass/combustion. MIU lights the SPORT indicator lamp.
Selector lever position	P, R, N, D, 4, 3, L	Trionic, MIU	TCM sends selector lever position, unit P, R, N, D, 4, 3, L. Trionic uses this value in airmass regulation for idle speed control. MIU uses the value to light the relevant segment in the selector lever display.
CHECK GEARBOX lamp	ON/OFF	MIU	When onboard diagnostics report that the lamp must be lit, ON is sent, unit ON/OFF. This value is used by MIU.
WINTER lamp	ON/OFF	MIU	When the WINTER driving programme is selected, the information WINTER ON, unit ON/OFF, is sent. MIU lights the WINTER indicator lamp.
Text message "TRANSMISSION OVERHEATING"	Text message	SID	When the fluid temperature in the gearbox exceeds 155°C, the information TRANSMISSION OVERHEATING, unit ON/OFF, is sent. The SID unit shows this message on its display.