GF00.20-P-0004SX Active Service System (ASSYST Plus), Function

GF00.20-P-0004SX Active Service System (ASSYST PLUS), Function
- MODEL 221.0 with ENGINE 156, 272, 273, 629, 642 up to Model Year 8
- MODEL 221.1 with ENGINE 156, 272, 273, 275, 629, 642 up to Model Year 8
- MODEL 216.3 with ENGINE 273, 275 up to Model Year 8

Shown on model 221.056 up to 31.8.06







The Active Service System PLUS (ASSYST PLUS) calculates the service date and determines further maintenance items. ASSYST PLUS uses measurements or values derived from measurements as well as data stored in its read-only memory to calculate the next service date for the vehicle. Both distance-related and time-related variables are taken into account. ASSYST PLUS can be configured, enabling it to be adapted to various vehicle uses. This is implemented in the central gateway control unit (N93). The central gateway control unit is connected via the central CAN, the chassis CAN and the drive train CAN to the following control units of the vehicle:
- Instrument cluster (A1)
- CDI control unit (N3/9), model 221 with engine 629 or with engine 642
- ME-SFI [ME] control unit (N3/10), model 216, model 221 except engine 629, except engine 642
- ESP control unit (N47-5)

Operation during the vehicle's first 250 km
ASSYST PLUS is primarily bound to the messages provided by the instrument cluster via the central CAN. The main odometer can be reset on the instrument cluster of the vehicle within the first 250 km. A reset on the instrument cluster is no longer possible after this limit of 250 km has been reached. ASSYST PLUS does not perform any maintenance item calculations until this distance has been reached. However, the travel distance of 250 km is taken into consideration in the calculation and evaluation of the maintenance items once when the main odometer reaches this threshold. ASSYST PLUS does not give this threshold further consideration. The following modules are integrated into the central gateway control unit:
- System diagnosis
- ASSYST PLUS

Data analysis
One or more service items and their intervals (travel distance, time, target date) are assigned to the basic items. All service events are stored in the history memory. They can be read out at any time using STAR DIAGNOSIS. The service calculation module calculates an optimum service scope from the data from all the integrated modules using an internal computation. This service scope takes the model designation, the date, the mileage, service-related special equipment (SA) and aftermarket installations into consideration.
Once the service date has been reached, the service indicator in the multifunction display of the instrument cluster is activated automatically via ASSYST PLUS.
The service scope can be displayed as the remaining distance or the remaining time in the multifunction display upon driver request or automatically when a warning threshold has been exceeded.

Technology and influencing factors
ASSYST PLUS takes the values of various variables into account to determine the service scope and interval. In addition to the evaluation factors, which depend on the real-life driving conditions, quality factors may also be used to determine the service scope and interval (remaining distance and remaining time).
Various measurements are needed for data recording purposes. The following data are read in via the central CAN:
- Vehicle speed
- Total odometer reading (km)
- Day cycle counter
- Date

The following data are read in via the chassis CAN:
Vehicle lateral acceleration
- Status of circuit 61
- Status of circuit 15 (indirect)
- Pedal value
- Engine speed
- Engine oil pressure
- Engine oil level
- Engine torque, static
- Engine torque, minimum and maximum
- Engine temperature
- Engine off time

ASSYST PLUS diagnosis is performed using STAR DIAGNOSIS. Access to this function takes place via the central gateway control unit.

Before the instrument cluster can be replaced, the trip odometer must be read out. Following this, the instrument cluster to be replaced can be replaced with a new one.

Before teaching in the key identification in the instrument cluster, the read-out trip odometer data must be written into the new instrument cluster.
Only then can the key identification teaching procedure be performed. If there is a fault in the instrument cluster or the EIS [EZS] control unit, no more service data are transferred. The last stored status of the service data is retained.

If a service confirmation has been erroneously performed on the instrument cluster or with the STAR DIAGNOSIS but no service has been carried out, this service confirmation must be reset as soon as possible within the following 250 km. Only the last confirmation can be undone.