Active Service System (Assyst Plus), Function - GF00.20-P-0004RD

Model 172.4

Function requirements, general

Terminal 15 ON

The electronic ignition lock control unit (N73) transmits the status of circuit 15 via interior CAN (CAN B) to the instrument cluster (A1).

Active Service System PLUS (ASSYST PLUS), general

ASSYST PLUS calculates when the vehicle is due for a service. This is done either after a precisely defined kilometer reading or after a certain time interval, depending on which limit is reached first. It also provides the driver or the service personnel with an overview of the scope of service operations for the vehicle.

The calculation is performed in ASSYST PLUS, which is integrated into the instrument cluster as a software solution. The ASSYST PLUS takes into account the time and distance-dependent additional operations in accordance with the vehicle equipment. The service scope and the point in time the inspection is due is shown in the multifunction display (A1p13) of the instrument cluster.

ASSYST PLUS comprises the following subfunctions:

Function sequence for determining the remaining distance
Function sequence for determining the remaining time
Function sequence for evaluating the data
Function sequence for service indicator
Function sequence for service interval reset

Function sequence for determining the remaining distance

The remaining distance is calculated from the difference of the defined kilometer reading and the distance already traveled. The distance traveled is defined via the wheel speeds.

The Electronic Stability Program control unit (N30/4) transmits information about the wheel speeds as of 01.03.2016 via chassis CAN 1 (CAN E1), front SAM control unit with fuse and relay module (N10/1) and chassis CAN 2 (CAN E2) and up to 29.02.2016 via chassis CAN (CAN E) to the instrument cluster.

The remaining distance to the next service is determined by means of the comparison to the travel distance reading that was reset and stored at the last service. The remaining distance is the primary decisive factor for the service indicator if the remaining distance is reached before the remaining time.

Function sequence for determining the remaining time

The remaining time is determined by ASSYST PLUS. The remaining time to the next service is determined by means of comparing with the point in time that was reset and stored at the last service. The remaining time is the primary decisive factor for the service indicator if the remaining time is reached before the remaining distance.

Function sequence for evaluating the data

Apart from the evaluation factors which depend on the real driving conditions, the ASSYST PLUS also takes into consideration quality factors for determining the service scope and intervals. To do so, the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends the following information as of 01.03.2016 via chassis CAN 1, front SAM control unit and chassis CAN 2 and up to 29.02.2016 via chassis CAN to the instrument cluster:

Engine speed
Engine oil level
Engine torque

Function sequence for service indicator

The following notes with service code can be shown in the multifunction display:

Service XX in XX days
Next service X
in XXXXX km or in XXXXX miles
Carry out service XX

In the event that the service date was exceeded, the following messages are shown:

Service XX has been due for XX days
Service XX has been due for XXXX km/miles

The service due is displayed to the specific day. The two-digit service code provides information on the scope of the operations to be carried out. The service scope is shown as a service code (e.g. "A1").

The letter denotes the service scope, and the following digit or letter provides the workshop with information about additional operations.

This enables the workshop to already provide the customer with the most precise specifications possible on the time expenditure and expense of the due inspection when the appointment is made.

Function sequence for service interval reset

Pressing the O K button (S110s6) in the left multifunction steering wheel button group (S110), service can be reset. The steering wheel electronics (N135) directly reads in the signals from the multifunction steering wheel button group and sends these via the steering LIN (LIN E1) to the steering column tube module control unit (N80). The steering column tube module control unit sends this as of 01.03.2016 via chassis CAN 1, front SAM control unit and chassis CAN 2 and up to 29.02.2016 via chassis CAN to the instrument cluster. The multifunction display shows the message "Next service". "Reset the maintenance interval" appears in multifunction display if O. K. button is pressed for longer than t = 3 s. The service interval is reset.

Should an exchange of the instrument cluster become necessary, the current service data must be entered manually. The following data is required for this:

Current kilometer reading/mileage reading
Current date
Kilometer reading/mileage reading when last oil change took place (from service booklet)
Date of the last oil change (from service booklet)
Calculation data of the ASSYST PLUS

Overview of system components, instrument cluster (IC) component description

GF54.30-P-9996RD