Engine oil information function - GF07.61-P-3026B

ENGINE 112.945 in MODEL 463.244 /245 /250 

ENGINE 113.962 in MODEL 463.247 /248 /249 /254 

Signal assignment oil sensor B40 

Task 

• The display in the instrument cluster warns the driver that the oil level is too low
• Detecting oil temperature
• Detecting the oil quality for indication of need-based oil change interval

Design/function 

The oil level, oil temperature and oil quality are detected by means of an oil sensor installed in the oil pan. The sensor operates in accordance with the capacitive measuring principle and features integrated electronics which analyze the three signals.

The information is constantly transmitted by means of a PWM signal to the engine control unit and via the CAN to the instrument cluster. Each information block consists of three successive square-wave signals, followed by a short pause. This is followed by a short pause. A measured variable is assigned to each square-wave signal (A, B, C). The quantisizing in each case is based on the on/off ratio of approx. 19 up to 81 %.

The oil quality is detected for the demand-based oil change interval display. The oil quality is detected on the basis of the capacitance of the engine oil (dielectrics), this being as much as 6 times greater in the case of poor oil quality.

The measuring range for the oil level is 80 mm (normal level ±40 mm), Measurement accuracy approx. ±3 mm.

Oil level and oil quality (capacitance of the engine oil) are independent of each other. The information is first of all compensated in the engine control module before it is transmitted over the CAN.

Faults at the oil sensor are detected by the engine control module and entered in the fault memory.

The voltage for the oil sensor (approx. 5 V) is supplied by the engine control module.