Electrically Heated Thermostat Control

M62 engine equipped E38 and E39 vehicles utilize an electrically heated thermostat to raise the engine's operating temperature in the part load operating range to improve fuel economy.







Control of the heated thermostat is an output function of the M5.2 module. The map controlled thermostat operates under the following parameters:

- Engine load
- Engine speed
- Vehicle speed
- Coolant temperature
- Intake air temperature

During part load running, the operating temperature of the engine is raised to approximately 110 °C, based on all operating parameters.







When operating at higher loads the thermostat heater is switched ON. The added heat of the element causes the thermostat to open earlier than it would have from the water temperature alone.

The heater is also switched on with excessive temperatures (> 113 °C).