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

GF00.20-P-0004RT Active Service System (ASSYST PLUS), Function
- MODEL 251.1 /0 up to Model Year 8

General information
The calculation of the service date is determined via ASSYST. Other maintenance items are carried out by ASSYST PLUS.
ASSYST PLUS determines, from measured values or variables determined there from 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 and evaluated. 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 engine compartment CAN (CAN-C) and interior compartment CAN (CAN-B) to the control units in the vehicle and to the instrument cluster (A1). 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 modules, such as ASSYST.
ASSYST only takes into account the oil change intervals; ASSYST PLUS covers all vehicle maintenance requirements. ASSYST PLUS is implemented as a module in parallel with ASSYST.

Operating characteristics during the first 250 km or 150 miles of the vehicle
ASSYST PLUS is primarily associated with the CAN messages provided by the instrument cluster. The main odometer can be reset on the instrument cluster within the vehicle's first 250 km or 150 miles. An instrument cluster reset is no longer possible after the 250 km or 150 miles limit has been reached. ASSYST PLUS does not perform any maintenance item calculations until this distance has been reached.

However, the driven travel distance of 250 km or 150 miles 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:
- System diagnosis
- ASSYST
- ASSYST PLUS

Data analysis
The assessment of the engine oil is determined via the oil sensor (oil level, temperature and quality) (B40) using ASSYST (only engine 113.971).
Individual or a number of stored service items with their intervals (km and/or time, target date) are assigned to the basic items.
All service events are stored in the history memory and can be read out at any time via 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 and retrofitted installations into consideration.
If the service date has been reached, the service display in the instrument cluster is activated automatically via ASSYST PLUS.

Display
The displays are shown in the multifunction display (A1p13) in the instrument cluster. The following instructions can be displayed with service codes:
- Service X in X days
- Service X in X km or miles
- Carry out Service X

The service date is displayed at least 1000 km or 500 miles or 30 days before the next service is performed. The service indicator consists of the word "Service" followed by the appropriate service code and "+" if necessary (optional).
The service code includes the time taken and is classified from A to H:
- Code A: service scope of up to 1 hr.
- Code B: service scope of up to 2 hrs.
- Code H: service scope of up to 8 hrs.

The service interval can also be displayed in the multifunction display upon driver request or automatically as the remaining distance when a value exceeds a warning threshold.

Engine oil monitoring (only engine 113.971)
In the multifunction display the oil starvation or the oil overfilling is displayed as a service 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 assessment of the engine oil quality, the service interval for gasoline engines is 15,000 to 40,000 km or 10,000 to 20,000 miles.

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). For the recording of data, various measured values are required which are put together as follows.

The following data from the CAN-B is required:
- Connection status of circuit 15 (indirect)
- Vehicle speed
- Total odometer reading (km)
- Day cycle counter
- Date
- Circuit 61

The following data from the CAN-C is required:
- Pedal value
- Engine speed
- Cylinder shutoff
- Oil pressure
- Oil temperature
- Oil level
- Oil grade (only engine 113.971)
- 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) to obtain the oil level and the engine oil temperature.

These are input by ASSYST in the central gateway control unit and are used for calculating the service times (only engine 113.971).

ASSYST PLUS diagnosis is performed using STAR DIAGNOSIS. Access to this function takes place via the central gateway control unit, which is connected to CAN diagnosis (CAN-D).

The next service date is calculated via ASSYST PLUS in the central gateway control unit and shown in the multifunction display.

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

Before teaching the key ID in the instrument cluster, the read-out trip odometer must be written to the new instrument cluster. Only then can the key ID teach-in procedure be performed.
In the event of an error in the instrument cluster or in the electronic ignition switch control unit (N73) no more service data will be transmitted and these will remain at the last updated status.

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