Active service system (ASSYST PLUS), function - GF00.20-P-0004SK: Notes

MODELS 171.4 with ENGINE 271.944 up to 31.5.05, 113.989 

General information 

The active service system PLUS (ASSYST PLUS) calculates when the service is due and determines further maintenance items. ASSYST PLUS determines, from measured values or variables determined therefrom as well as from data stored in its read-only memory, the next service date due for the vehicle in question. 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 (N93) is connected to the vehicle's control units and the instrument cluster (A1) via the Controller Area Network bus class B (interior) (CAN-B) and the Controller Area Network bus class C (engine compartment) (CAN-C).

During configuration of the maintenance algorithm, it is determined whether the required data are acquired solely by the system or data are taken from other functions such as the calculation of the brake lining wear. ASSYST PLUS takes the entire vehicle maintenance into account. The brake algorithm is also implemented in ASSYST PLUS in addition to the maintenance algorithm and from the brake data determines the instantaneous remaining distance for the vehicle brake.

Operation during the vehicle's first 250 km 

ASSYST PLUS is primarily linked to the messages prepared by the instrument cluster (A1) via the Controller Area Network (data bus/ CAN Bus) (CAN). The main odometer can be reset on the instrument cluster (A1) within the vehicle's first 250 km. An instrument cluster (A1) reset is no longer possible after the 250 km limit 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 threshold is reached. This main odometer threshold is not taken into consideration again by ASSYST PLUS.

The following modules are integrated into the central gateway control unit (N93):

• System diagnosis
• ASSYST PLUS
• Target date for main inspection/emissions inspection

Data analysis 

The engine oil evaluation is performed by the oil sensor (oil level, temperature and quality) (B40) via ASSYST PLUS. 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 have arrived, the service indicator in the upper multifunction display (A1p13) of the instrument cluster (A1) is activated automatically via ASSYST PLUS.

Display 

It is displayed in the upper multifunction display (A1p13) in the instrument cluster (A1). The following instructions can be displayed with service codes:

• Service X in XXX days
• Service X in XXXXX km or miles
• Carry out Service X

A "+" after the service indicator identifies the degree of wear of the brake linings. The brake lining thickness must be checked on the service date. The display of the service date appears no sooner than 1000 km or 30 days before the next service date. The service indicator shows the term "Service" followed by the particular service code and "+" (optional) if necessary.

The service code refers to the time taken for the work and is classified from A to H:

• Code A indicates a service scope of up to 1 hr.
• Code B indicates a service scope of up to 2 hrs.
• Code H indicates a service scope of up to 8 hrs.

The service interval can also be displayed in the upper multifunction display (A1p13) upon driver request or automatically as the remaining distance when a warning threshold is exceeded.

Engine oil monitoring 

In the upper multifunction display (A1p13), the oil starvation or the oil overfilling is displayed as an oil can symbol with text. In addition, it is possible to detect oil replenishments. If oil is replenished, a bonus is issued which may extend the service interval. Depending on the evaluation of the engine oil quality, the service interval on gasoline and diesel engines is 15, 000 to 40, 000 kilometers.

The information on the engine oil quality can be taken into account when determining the service interval. In order to do this, STAR DIAGNOSIS has to be connected and appropriate changes made in the "General Maintenance" and "Confirm Overall Maintenance" menu items.

Technology and influencing factors 

ASSYST PLUS needs the values of various influential parameters to calculate the requirement-based service interval. In addition to the evaluation factors, which depend on the real-life driving conditions, quality factors may also be used to determine the monitored service interval (remaining distance and remaining time). Various measurements are needed for data recording purposes.

The following data from the CAN-B is required:

• Circuit 15 (indirect)
• Vehicle speed
• Total odometer reading (km)
• Trip odometer
• Date
• Terminal W alternator (engine speed) (Circuit W)

The following data from the CAN-C is required:

• Pedal value
• Engine speed
• Oil pressure
• Oil temperature
• Oil level
• Oil quality
• Engine torque, static
• Engine torque, maximum
• Engine torque, minimum
• Engine temperature
• Engine off time
• Vehicle lateral acceleration

The ME control unit (N3/10) reads in the data from the oil sensor (oil level, temperature and quality) (B40) to obtain the oil level and the engine oil temperature. These are read in by the ASSYST PLUS in the central gateway control unit (N93) and used to calculate the service date.

ASSYST PLUS diagnosis is performed using STAR DIAGNOSIS. Entry to this function takes place via the central gateway control unit (N93).

In addition to calculating the next service date, the indication for the next main vehicle inspection date and the exhaust emissions inspection date are calculated and displayed in the upper multifunction display (A1p13) using ASSYST PLUS in the central gateway control unit (N93).

Before the instrument cluster (A1) can be replaced, the trip odometer must be read out. Following this, the instrument cluster (A1) to be replaced can be replaced with a new one.

Before teaching the key identification in the instrument cluster (A1) the read-out trip odometer must be written to the new instrument cluster (A1). Only then can the key identification teaching procedure be performed. If there is a fault in the instrument cluster (A1) or the EIS control unit (N73), no more service data are transferred. The last up-to-date service data that were stored are retained.

If a service has been erroneously confirmed on the instrument cluster (A1) or with the STAR DIAGNOSIS but no service has actually been carried out, this service confirmation must be reset immediately. Only the last confirmation can be reset.

Active service system (ASSYST PLUS), operating instructions		GF00.20-P-0004-01SK
Active Service System (ASSYST PLUS), driver information	Service indicators	GF00.20-P-0004-02SK
	Oil warnings	GF00.20-P-0004-02SKA
	Maintenance indicators	GF00.20-P-0004-02SKB
Display service scope, function		GF00.20-P-2010SK
Read out service memory, function		GF00.20-P-2012SK
Remaining distance, function		GF00.20-P-2007SK
Remaining time, function		GF00.20-P-2008SK
Engine oil monitoring, function		GF00.20-P-2009SK