Engine Oil Monitor Function

q


General
The oil level is constantly being monitored and the respective data passed on to the ASSYST computer by the oil sensor (oil level, temperature and quality 640).

Topping up with oil is automatically recognized and results in a bonus, which extends the service interval accordingly. Overfilling or low oil level will be displayed in the multifunction display (A1p13) of the instrument cluster (A1) together with the oil can symbol.

Display of oil warnings is accomplished:
- Automatically, earliest 60 sec. after engine start and with an oil temperature greater than 60 °C:
- In the event of over filling: The oil can symbol will appear together with the message "REDUCE OIL LEVEL!". In addition, a short acoustic sound is also generated.
- With a critically low oil level or poor oil condition (Water in oil): The oil can symbol will appear together with the message "ENGINE OIL, CAR TO WORKSHOP!". In addition, a short acoustic sound is also generated.
- With min. oil level: Oil can symbol together with the message "CHECK ENGINE OIL LEVEL!". In addition, a short acoustic sound is also generated.

- Automatically, 13 sec. after ignition ON:
- If the oil level has dropped to an oil level where it can damage the engine: the oil can symbol will appear together with the message in red lettering "ENGINE OIL, STOP, SWITCH ENGINE OFF! ". In addition, a short acoustic sound is also generated.

Oil quantity display
- Turn ignition switch to position "2".
- Operate the system selection button (S110s3) until the complete overview (total mileage and trip odometer) is displayed in the multifunction display (A1p13). (Only required, if the complete overview is not yet displayed.)
- Operate the forward and backward scrolling button (S110s1) until the message "ENGINE OIL, CAR MUST BE LEVEL" appears in the multifunction display (A1p13).
- If the car is not level, interrupt the measurement by stopping operation of these buttons within 3 sec.
- If the measurement is not interrupted after approx. 3 sec. the message "ENGINE OIL MEASURING IS RUNNING".
- Message in the event of faults in the measuring system:
- "ENGINE OIL LEVEL IN ORDER"
- "REDUCE ENGINE OIL LEVEL"
- "TOP UP OIL WITH 1.0 L OIL"
- "TOP UP OIL WITH 1.5 L OIL"
- "TOP UP OIL WITH 2.0 L OIL"
The quantity of oil to use for topping up is given in either liters (L) or quarts (Q).
- If the message "MEASUREMENT NOW NOT POSSIBLE", the waiting time has not been adhered to.


NOTE: The missing oil quantity message is not changed during the display. A change in the oil level can therefore not be observed directly at the display. The new oil level will only be displayed after the following conditions have been satisfied.


Waiting time
Oil level measuring is only possible after the engine has been switch OFF for a certain time.

If the driver attempts to interrogate the oil level with the engine RUNNING, the message "ENGINE OIL LEVEL NOT WITH ENGINE RUNNING".

The waiting time after the engine has been switched OFF depends on the engine oil temperature.

This is as follows
- up to 20 °C 30 min
- as of 60 °C 1 min
- With other temperatures the waiting time will vary accordingly.

Display of errors in the measuring system
In case of error of the measuring system, e.g. an error of the oil sensor (oil level, temperature and quality, B40), at the earliest 30 sec. after the error has occurred, the oil can symbol and the message "ENGINE OIL LEVEL, GO TO GARAGE!" will appear. For the diagnosis the injection system (N3) control module must also be read out with the Star diagnostic tool.

The instrument cluster (A1) receives the sensor data from the injection system (N3) control module via the CAN bus engine compartment

Oil change
The ASSYST must be reset after every oil change. Resetting will also reset the remaining mileage and remaining time. Resetting can be carried out via the instrument cluster (Al) or the Star diagnosis too!.

When resetting, the following data is stored:
- the actual km reading, rounded up to 100,
- topping up quantities in the last interval,
- outstanding remaining mileage,
- outstanding remaining time,
- results of the quality factors.
- in five data sets the data of the last five resets

This data can be read out with the Star diagnosis tool.
If, during the oil change, the specified quantity of oil is not used, the initial mileage (internal mileage) is reduced.


NOTE: (The procedure for resetting via the instrument cluster is described in the document "Operating method".)


Topping up recognition
- The Star diagnosis tool can be used to call off the last 10 topping up quantities and the respective km readings of the actual interval.
- A topping up recognition is normally indicated in the instrument cluster by an extension of the remaining mileage.

Adding oil is recognized only when the following conditions are fulfilled:
- the topping up quantity is at least 1 qt.
- after topping up of the oil at least 5 km must be driven under normal driving conditions and with an oil temperature of at least 60 °C.

There are, however, instances where the display of the remaining mileage still appears to be wrong after topping up of the oil; according to the display, no bonus or only a minor one will be awarded.

The reason for this is that the remaining mileage is always displayed only over the range of 15000 km to 30000 km (or 10000 miles to 20000 miles), but that internally the actual values are used for the calculations, although these values could well be outside this range.. These internal values can only be displayed with the Star diagnosis tool.

The following diagrams will therefore show some example, whereby the horizontal axis (x-) axis represents the service interval and the vertical (y-) axis the remaining mileage in km.

The ASSYST display in the instrument cluster always moves in the light range, whilst the internally calculated remaining mileage can also be found in the two darker areas. These internal values can only be displayed with the Star diagnosis tool.







Example 1:
During the oil change the specified quantity of oil was used.

The initial mileage therefore is 15000 km.

After 10000 km, and under normal driving conditions (a), the oil is topped up. The bonus (B1) is awarded and displayed. This means that, on call-up of the remaining mileage, a greater remaining mileage is displayed. (Provided the previously mentioned conditions for recognition of topping up have been satisfied) After a further 5000 km (b) the oil is topped up again. Here again a bonus (B2) is awarded and displayed.

If the oil is not topped up again and the same driving conditions apply, a service interval of 24000 km will be achieved. In this example the curve is completely in the light area of the diagram, so showing all oil refills in the extension of the remaining mileage.







Example 2:
During the oil change the specified quantity of oil was used.

Under very favorable driving conditions the oil is topped up after 10000 km (a).

Internally the bonus (B1) is awarded and the service interval is extended accordingly by a remaining mileage. As the curve, however, is in part in the shaded area, only that part of (B1) which is in the light area is initially displayed as extension of the remaining mileage. (Provided the previously mentioned conditions for recognition of topping up have been satisfied)

At 18000 km the oil is topped up again (b). Due to exceeding the max. service interval of 30000 km, the bonus (B2) does not show an extension. The complete service interval, is in this case, 30000 km.

If driving is continued from point b onwards under less favorable driving conditions, it is possible to achieve the max. service interval of 30000 km because of the internal bonus (B2).







Example 3:
During an oil change less oil than specified was used, the initial mileage was therefore less than 15000 km. The indicated remaining mileage is nevertheless 15000 Km.

If now, after 5000 km, the oil is topped up (a), the remaining mileage is not increased, as the curve is in the shaded area. However, the bonus (B1) is computed internally and shows that, under identical or better driving conditions, an extension of the service interval to slightly over 15000 km.


NOTE: The service interval of 15000 km will always be achieved, even with less internal value.







Example 4:
During the oil change the specified quantity of oil was used.

After 5000 km of unfavorable driving conditions the oil was topped up (a) and the topping up (Bonus B1) was recognized internally.

Now two cases must be considered:
- If the operating conditions remain the same (solid line), the remaining mileage displayed is not increased, because the curve remains in the shaded area.
The service interval in this case is nevertheless 15000 km, although the internal value is smaller. (The indicated remaining mileage is continuously in the light area.)
- If driving now continues under the same conditions (dotted line), the value of the internal remaining mileage moves slowly into the light area.
This enables the service interval to become greater than 15000 km