Oil Level Sensor

Oil Level Sensor







The oil level sensor is a PULS (Packaged Ultrasonic Level Sensor) sensor. The advantage of this sensor is that it can detect both a minimum and maximum oil level as well as overfills. It works according to the principle of ultrasonic measurement.







The ultrasonic sensor is a continually operating sensor system for recording the engine oil level. The determined fill-level data is supplied via a pulse-width modulated signal. The displayed oil level is calculated from a long-term mean value. The mean value is calculated on 100 km and 3600 measured values. When the mean value has been calculated, the last mean value is stored and mean value calculation starts all over again.

Oil Level Sensor System Diagram










Only measured values that were formed within certain temperature, engine speed, vehicle speed and lateral acceleration thresholds (enabling signal from DME) are used for calculating mean values. The last mean value is always displayed in the Oil menu. An oil level is always displayed. Exception: No oil level is displayed for approx. 6 miles (10 km) after the hood has been opened, but the message "Display after short drive only" is displayed.

Mean value calculation is restarted after the hood has been opened. The oil level can be displayed if at least 360 measured values are used to calculate the mean value over a distance of at least 6 miles (10 km).

The warning message for max/min oil level is formed based on the long-term mean value. There are two minimum thresholds: Minimum oil level reached (yellow warning, appears only when terminal 15 is off), Oil level below minimum (yellow warning, also appears while driving). No oil level warnings are displayed after the hood has been opened and until such a time as the long-term mean value has been calculated again.