GF00.20-P-0003RI Active Service System (ASSYST), Function

GF00.20-P-0003RI Active Service System (ASSYST), Function
- MODEL 230.4 as of model year 09/YoM 08 model refinement package

General function requirements
- Circuit 15 On

System in general
The Active Service System (ASSYST) determines each respective service date for the vehicle. As well as distance-dependent and time dependent variables, quality factors are also taken into consideration in the determination of the service scope and the service interval. These are shown on the left multifunction display (A1p13) and the right multifunction display (A1p15) in the instrument cluster (A1).

ASSYST consists of the following subfunctions:
- Function sequence for determining the remaining distance
- Function sequence for determining the remaining time
- Function sequence for service display
- Function sequence for service reset

Function sequence for determining the mileage
The warning threshold for the remaining distance is primarily decisive for the service warning if the remaining distance reaches the service warning threshold before the remaining time. The warning threshold is stored in the maintenance computer (ASSYST computer). When the remaining distance is being determined, the wheel speed detected by the left front rpm sensor (L6/1), the right front rpm sensor (L6/2), the left rear rpm sensor (L6/3) and the right rear rpm sensor (L6/4) is read in by the SBC control unit (A7/3n1) and relayed to the ESP, SPS [PML] and BAS control unit (N47-5). The ESP, SPS [PML] and BAS control unit relays the signals to the instrument cluster via the engine compartment CAN.
The instrument cluster calculates the travel distance from values received. The remaining distance to the next service is determined by the counter-check with the travel distance reading stored at the last service.

Function sequence Mileage weighting
The following driving conditions are taken into account for the weighting of the mileage:
- Cold starts
- Engine speeds
- Short-distance trips

The remaining distance and thus also the maintenance interval can be extended or shortened by the weighting.
In the process it is also taken into account whether the vehicle is actually being driven or whether the engine is being operated at idle. The current operating conditions of the vehicle are transmitted from the ME-SFI [ME] control unit (N3/10) via engine compartment CAN to the maintenance computer, which evaluates the data transmitted accordingly. The best evaluation is 0.6 km for each actual kilometer driven.

The mileage weighting takes place in the background and does not affect the actual maintenance interval, but can be read out using STAR DIAGNOSIS.
A fixed interval of one year or 25,000 km is stored in the instrument cluster software.

Function sequence for determining the remaining time
The remaining time warning threshold is primarily decisive for the service warning, if the remaining time is reached before the remaining distance. The warning threshold is stored in the instrument cluster and can be read out using STAR DIAGNOSIS.

Function sequence for service display
A distinction is made between Service A and Service B. This is indicated by the service symbol (wrench) in the left multifunction display.
The relevant text message appears in the right multifunction display.

The service scope appears in the left multifunction display as follows:
- Service A (one service symbol)
- Service B (two service symbols)

The following text messages can appear in the right multifunction display:
- Service A/B in XX days
- Service A/B in XXXX km or miles
- Perform Service A/B
- Service A/B exceeded by XX days
- Service A/B XXXX exceeded by km or miles

The service date is displayed at least 1000 km or 30 days before the next service is due in the basic setting. The service scope provides information on the scope of the service operations to be performed.

Function sequence for service reset
The service interval can be reset using the instrument illumination brightness control and reset button (A1r1).
To do this, the brightness control must be pressed for longer than t = 3 s with the service indicator displayed. The confirmation question as to whether the service interval is to be reset then appears in the right multifunction display.

If the brightness control is pressed again within t = 5 s, the service interval is reset and the new initial remaining distance value appears in the right multifunction display.