Bus messages, TCM
For further information on the bus, see SYSTEM OVERVIEW, BUS AND DIAGNOSTICS COMMUNICATION, PETROL
The TCM uses the following information:
TCM USES INFORMATION
| Information | Unit | From | Description |
|---|---|---|---|
| Engine torque | Nm | Engine management system | The current air mass/combustion is converted into torque and given in Nm |
| Pedal position | % | Engine management system | The engine control module uses the highest requested values for air mass/combustion either from the pedal position or from the cruise control. The value is converted to a corresponding pedal position, unit %. |
| Kickdown | ON/OFF | Engine management system | When the voltage from pedal potentiometer 1 corresponds to the kickdown position (below 1.50 V), Kickdown ON will be sent. |
| Engine speed | rpm | Engine management system | Current engine speed, unit rpm. Additionally, the value is used to compare engine speed with the speed of the input shaft when Lockup is activated. |
| Brake lights | ON/OFF | TWICE | Brake lights, unit ON/OFF. |
| ENGINE JERK | ON/OFF | Engine management system | If engine surge has been detected by the engine management system a message is sent out on the bus and is used by TCM which then adapts the shifting points to avoid engine surge. |
| Reduced engine power | ON/OFF | Engine management system | Driving at high altitude (approx. 2,400 metres above sea level, pressure approx. 80 kPa) results in reduced engine power. TCM then uses a special shifting program which means that the engine is allowed to run at a higher rpm than normal. |
The TCM sends the following information:
TCM SENDS INFORMATION
| Information | Values | Used by | Description |
|---|---|---|---|
| Maximum permissible torque | Nm | Engine management system | The TCM sends the maximum permissible torque, unit Nm. The value is used in the mass air flow control circuit for torque limitation. |
| SPORT | ON/OFF | Engine management system, MIU | The TCM sends the sport position, unit ON/OFF. The value is used in the mass air flow control circuit to correct the pedal position's conversion into the requested air mass/combustion. The MIU causes the SPORT indicator lamp to light up. |
| Selector lever position | P, R, N, D, M, L Diesel: P, R, N, D, 3, 4, L |
Engine management system, MIU | TCM sends the selector lever position, unit P, R, N, D, M, and L. diesel: P, R, N, D, 3, 4, and L. The value uses the engine management system in the air mass control for idle speed control. MIU uses the value to light the appropriate segment in the selector lever display. |
| CHECK GEARBOX lamp | ON/OFF | MIU | ON is sent when on-board diagnostics reports that the lamp should be lit, unit ON/OFF. The value is used by MIU. |
| Text message TRANSMISSION OVERHEATING | Text message | SID | When the oil temperature in the transmission exceeds 155°C the information TRANSMISSION OVERHEATING is sent, unit ON/OFF. The SID unit will display this message. |
| Selected gear position | 1 - 5 | MIU | TCM sends out the message "Selected gear". This is used by MIU to display the current gear in position M. |