ECM Controlled Function
WARNING: This page does not describe the selected car, but rather 41 other vehicles, including the 2003 BMW M5, 2003 BMW M3, 2003 BMW 540i, 2003 BMW 530i, and 2003 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.
The map controlled heater in the thermostat will switch ON under the following conditions:
- Load signal "ti" > 5.8 ms
- Engine temperature "tm" > 113°C
- Intake air temp > 52°C
- Vehicle speed > 110 MPH
When the heating element is switched ON, the thermostat is heated higher than the temperature of the coolant.
The thermostat opens sooner causing additional coolant to circulate through the radiator which brings the temperature down.
The temperature of the coolant at the inlet side of the water pump will drop to approximately 85°C and the temperature at the outlet side of the water pump will drop to approximately 103°C.
NOTE:
- If the coolant temperature is below 85°C, the heater will not switch on for any condition.
- The display characteristics of the temperature gauge in the instrument cluster have been calibrated to the higher engine temperatures.