Functional description, see BMW Service Technology:
TIS -> Document -> SI Technology -> Enter SBT Number
SBT number:
The engine cooling works according to the crossflow principle with a horizontally split radiator. The electric fan is monitored and activated by the DME.
Two sensors report the coolant temperatures to the DME:
The two sensors are monitored by the DME; corresponding faults are entered in the fault code memory.
The coolant thermostat is of conventional design and it opens as of a coolant temperature of 79 °C. The thermostat is not activated by the DME. Via the course of the coolant temperature, the DME still recognises if the thermostat remains open due to a defect after a cold start.