BMW: DIAGNOSIS OF DME ME 9.2 MAP THERMOSTAT FAULT 2EF4/279B. THE SERVICE ENGINE SOON LIGHT ILLUMINATED. THE ENGINE DOES NOT OVERHEAT AND THE MAP THERMOSTAT OPERATES PROPERLY. POSSIBLE CAUSES ARE DETERIORATION OF COOLANT QUALITY; INCREASED CONTACT RESISTANCE BETWEEN THE THERMOSTAT TEMPERATURE SENSOR, THE ENGINE WIRING HARNESS AND THE DME CONNECTOR; INTERNAL DEFECT OF A MAP COOLING THERMOSTAT. *PE UPDATED 11/17/10. *PE