Electronic oil checking
The oil level is measured for the electronic oil level check. The 2nd capacitor in the upper part of the oil condition sensor registers the oil level with the engine running. The capacitor is at the same level as the oil level in the oil sump. As the oil level changes, the capacitance of the capacitor changes. The electronic evaluation unit creates a digital signal from this. The engine-management system employs this as the basis for calculating the engine's oil level. The electronic oil level check is displayed on the Central Information Display (CID) as well as in the instrument panel. On vehicles without CID, the oil level is only displayed in the instrument panel.
Display options in the instrument panel
| Item | Explanation |
|---|---|
| 1 | Oil level OK |
| 2 | Oil level at minimum |
| 3 | Oil level too high |
| 4 | Oil condition sensor has failed |
| 5 | Oil level is being determined |
Display options at the Central Information Display
| Item | Explanation |
|---|---|
| 1 | Oil level below minimum (display red) |
| 2 | Oil level at minimum (display orange) |
| 3 | Oil level OK: 1/4 (display green) |
| 4 | Oil level OK: 1/2 (display green) |
| 5 | Oil level OK: 3/4 (display green) |
| 6 | Oil level OK: Maximum (display green) |
| 7 | Oil level above maximum: overfilled (display orange) |
| 8 | No measured value present: oil level is being measured |
| 9 | Sufficient oil in the engine for short-term engine start (service function on oil change) |
Notes for Service department
General notes
Condensate that forms in the crankcase due to short distance driving can influence the permittivity. As water enters the engine oil and mixes with it, moisture also collects around the oil level sensor. When excessive moisture or water is present within the crankcase: Individual instances of incorrect oil level displays may occur, while a spurious warning indicating that the oil should be topped up is also possible. The diagnostic system can process this "spurious oil-level warning" with fault pattern selection in an operation that also assesses the permittivity of the oil. However, there is no direct display of the permittivity. Among the factors that affect the oil's permittivity are its viscosity and its age. This means that an accurate assessment of oil quality cannot be guaranteed under all conditions.
The display messages available for the electronic oil level check can be found in the Owner's Handbook.