Cruise control, general
Cruise control is operated with a switch on the direction indicator stalk. The switch is an integrated part of CIM (703), which sends the position of the switch as a bus message.
This bus message is used by ECM for the cruise control function. When the switch is put to "ON", the "CRUISE" lamp on MIU will come on. Pushing the "SET" button on the switch will store the current vehicle speed in ECM memory provided all the criteria for activating cruise control have been fulfilled.
ECM then reads from a table in which the nominal rolling resistance on a flat surface at different vehicle speeds is stored. This results in an engine torque request to maintain a constant speed.