General Information

General
The "Active Service System" (ASSYST) draws the driver's attention to a scheduled service and the attendant scope of service work (A/B).

ASSYST is a requirement-oriented engine-oil maintenance system. Next to its purely time and distance criteria, various factors are taken into account when calculating requirement-oriented service intervals.

On the one hand, these are quality factors, which are coded with the Star Diagnosis tool, and on the other hand, assessment factors, which take driving conditions and by inference effective wear into account.

In a favorable assessment (few cold starts, vehicle driven mainly in middle engine-speed range) the service interval is larger than for an unfavorable assessment.

Display
Displays are shown on the multifunction display (A1p13) of the instrument cluster (A1).

The service interval is displayed when the driver requests it or when a warning threshold is overstepped automatically as a remaining distance or time in the text fields (1,3) together with the service symbol (2) in the multifunction display (A1p13) (Fig.1).

Engine-oil monitoring
In the event of too little or too much oil the text fields (1,3) display information about the oil level (Fig. 2) on the multifunction display (A1p13). This is backed up by a displayed oil can symbol (2).

Beyond this the system recognizes when oil has been refilled. If the oil is topped up, a bonus is given which may extend the service interval.

Depending on the assessment and bonuses the service interval for gasoline engines lies between 15000 to 30000 kilometers or 10000 to 20000 miles, for diesel engines between 20000 and 40000 km.

Technology and influencing variables
In order to calculate a requirement-oriented service interval the ASSYST system requires the values of various variables, which are used to calculate both the service interval and scope of the service work (A or B).

Alongside assessment factors, which are dependent on real-life driving conditions, the calculation of the requirement-oriented service interval (remaining distance and time) refers to quality factors.

Variables
- Assessment factors (dependent on real-life driving conditions):
- Load moment
- Speed
- Oil level
- Engine-oil temperature
- Oil correction factor (serves as comparison value for determining nil level)
- Coolant temperature

The instrument duster (A1) is sent this information via the CAN engine compartment from the injection system control module (N3).

Far the oil level, engine-oil temperature and oil correction factor data, the injection system control module (N3) reads out the data from the oil sensor (oil level, temperature and quality B40).

- Quality factors (Set to default values at factory). They can be called up via the Star Diagnosis tool should the situation require it, and be altered. They exert an influence on the start mileage.):
- Engine version factor (gasoline/diesel)
- Country factor (Mileage is coded according to specific country.)

- Mileage:
In order to calculate the mileage, the ASSYST system is sent the four wheel speed sensor signals from the traction system control module (N47) via the CAN engine compartment.

- Time
ASSYST receives its time data from a timer integrated into the instrument cluster (A1).


NOTE: The majority of documents contain illustrations with information shown on the multifunction display (A1p13). Displays are always for the Models 208, 210, 215 and 220. The displays for Model 203 varies very slightly.







Service display example


NOTE: Further displays are available in other documents, in particular, in the "Active Service System (ASSYST) Mercedes-Benz Driver Information Service" document.







Engine-oil display example


NOTE: Further displays are available in other documents, in particular, in the "Active Service System (ASSYST) Mercedes-Benz Driver Information Service" document.


NOTE: Diagnosis
The ASSYST diagnosis is conducted with the Star Diagnosis tool. This is accessed via the instrument cluster (A1). During diagnosis the injection system control module (N3) is also taken into account.


NOTE: Inadvertent oil change reset
If an oil change reset is entered on the instrument cluster (Al) or via the Star diagnosis tool, but no oil change was actually made, the oil reset must be canceled. A menu is available in the Star Diagnosis tool for this purpose.


NOTE: Replacing the instrument cluster (A1)
If the instrument cluster (A1) needs to be replaced, the codes and data records must be transferred to the new instrument cluster.

NOTE: Replacing the oil sensor (oil level, temperature and quality B40)
Should complaints arise after replacing the oil sensor (oil level, temperature and quality B40) it may be necessary to reset (recalibrate) the oil minimum level indicator. This must always be done when the "CHECK ENGINE OIL LEVEL!" display appears, but the oil level is OK according to the dipstick reading. Calibration is done by menu with the Star diagnosis tool.