Condition Based Service - Overview: Other BMW 7 series E65/E66 facelift

Purpose of the System

The current Service Interval Indicator systems (SIA3 and SIA4) determine maintenance intervals based on fuel consumption, which is done to assess the need to change the engine oil. The main determining factor for the maintenance interval currently is the condition of the engine oil. Other maintenance needs, including the replacement of wear and tear items, are arranged to coincide with due engine oil changes.

On the E65/E66, BMW is measuring the need for maintenance of several critical components besides the engine oil, and independently of the engine oil. This would theoretically afford us the ability to bring a vehicle in for service whenever one of the measured components requires maintenance or replacement. However, customers would be inconvenienced because the maintenance intervals would be dramatically reduced.

Condition Based Service (CBS - further development of SIA) strikes a compromise between too frequent maintenance and too rigid intervals which call for the replacement of maintenance items that may still have substantial useful life left. The objective is to furnish economical maintenance by providing the ideal service for individual vehicles.

Sensor Based CBS Service Items

The trend in the vehicle service business is to lengthen service intervals and reduce replacement of maintenance items. Additional measures have been taken to keep the vehicles in a roadworthy and comfortable condition.

Usage dependent maintenance of select wear and tear items is detected by physical and virtual sensors. This means that, in cases where the wear is not measured directly, the service due date will be determined by using auxiliary variables such as mileage, vehicle performance, temperature, etc.

Sensors built into certain components and control module algorithms take even more detailed account of the various conditions of vehicle use. The remaining times for selected maintenance tasks as well as any dates for State and/or Emissions Inspections (determined by the state in which the vehicle is registered) are individually displayed.

CBS determines the current and future maintenance requirements. The current status of Service items determined by CBS are shown in the Control Display. This data can also be read from the vehicle key by using the Key Reader, as the vehicle's current service status is automatically saved in the ignition key every time the key is used to operate the vehicle.

Three sensors detect the following wear conditions

1. Engine oil (sensor)
2. Micro filter (virtual sensor)
3. Front and rear brake linings (sensor as reference point)

The instrument cluster collects the values from the wear detection control modules and manages the internally defined service schedule. Data exchange is carried out on the bus systems.

Internal Calculation Of CBS Service Items

For certain wear and tear items, sensors are not needed by the Condition Based Service. The wear items that are calculated and managed internally by the instrument cluster are

1. Brake fluid
2. Coolant
3. Spark plugs
4. Visual and functional checks (vehicle check)
5. Official State Safety and/or Emissions Inspections

The maintenance of these items is performed at fixed intervals. The residual wear or the remaining time to next service is calculated by the instrument cluster using the travel/time parameters of: mileage, current date and internal distance counter. When a service item is due, it is shown in the instrument cluster or the Control Display.

Note. The internal distance counter plays a particular role. Unlike the Time/Date, this counter cannot be set by the driver.

However, battery down times (battery cut off by the distribution switch) also stop the trip distance counter which leads to longer time based service intervals. This will disrupt the CBS volumes for engine oil, microfilter, brake fluid and coolant.

To correct this, the internal counter status must be reset by the DISplus/GT1. The wear dependent items internally calculated by the instrument cluster are stored in the instrument cluster and in the CAS control module (redundancy).

Note. The instrument cluster and the CAS must not be replaced simultaneously, otherwise all current oil maintenance schedule data will be lost.

Service Indications

Regarding CBS, there are three different service indicators

1. Service need display (SBA) in the instrument cluster (base of speedometer)
2. Check Control display in the instrument cluster (base of tachometer)
3. CBS indicator in the Control Display

Service Need Display (SBA)

The Service Need Display is the evolution of the SIA4 Service Interval display. When KL15 is "ON," the Service Need Display appears under the speedometer in the instrument cluster for 10 seconds in the place where the fuel tank level is normally displayed.

The first line corresponds to the mileage dependent service items. It specifies the mileage when the next service is due. If the mileage is exceeded (service overdue), it appears with a minus sign.

The second line corresponds to the time dependent service items and is displayed by a clock symbol. It specifies the weeks/months/years when the next service is due. If the service is overdue, it appears with a minus sign.

Scheme 35

The actual service item (with additional information) can be viewed in the Control Display.

Check Control Message

The CBS produces a Check Control message that indicates the brake lining wear at the front or rear axle. When the brake linings are worn, this is shown as follows

Scheme 36

1. The general brake warning lamp and the variable control lamp come on in the instrument cluster.
2. The variable control lamp shows the symbol of a car on a lifting platform.

A brief Check Control message appears: "Service, see Vehicle menu." For more detailed information, the user can access the Control Display.

CBS Indicator In The Control Display

The Control Display provides additional information on service and maintenance procedures by selecting the "OB data" menu.

After releasing the Controller or returning to the central position, the "On-board data" menu appears.

Scheme 37

Turn the Controller to the left until the bottom left button is highlighted (vehicle symbol).

Confirm your selection by pressing the Controller.

Scheme 38

The CBS menu appears with the service items.

The Control Display shows a list of selected service and maintenance procedures, as well as legally-mandated official inspections.

Scheme 39

Now you will see a service road in the Control Display. The service and maintenance procedures are displayed in different colors

Scheme 40

1. Green: No service is currently required
2. Yellow: Service deadline is approaching
3. Red: Service deadline has already passed

The service items highlighted in red with the highest priority appear in the bottom part of the display.

You can scroll through the list of service and maintenance procedures from top to bottom by turning the Controller from right to left. You can leave the list of service items by pressing the button with the Up arrow symbol.

The service and maintenance items are

1. Engine oil
2. Front brake pads
3. Rear brake pads
4. Ventilation system microfilter
5. Brake fluid
6. Coolant
7. Spark plugs
8. Vehicle check
9. State Inspection
10. Emissions Inspection

To display the service and maintenance item information in the Control Display, turn the Controller to select the item and confirm your selection by pressing the Controller.

For the "Spark plugs" service and maintenance item, for example, the following information appears

Scheme 41

1. Service due 9000 mls, Have your BMW Center replace the spark plugs.
2. Button with arrow symbol

You can exit this menu by pressing the button with the arrow symbol at the bottom left. The lowest menu automatically closes after a short time (timeout) if you do not touch the controller. In the same way, you can access the full text for each service item.

CBS Correction Tester Data

The CBS correction tester data allows "quick access" to create or change the basic data (stored in the tester) for the CBS handover inspection. When the CBS handover inspection is carried out, the changed data in the tester is automatically transferred to the vehicle.

The CBS correction tester data includes

Scheme 42

1. Change telephone numbers Mobile Service Customer Hotline Local Dealer
2. State Inspection presettings Display/activate State Inspection (interval) Display/deactivate State Inspection
3. Emission Inspection presettings Display/activate Emission Inspection (interval) Display/deactivate Emission Inspection

CBS Correction Vehicle Data

The CBS correction vehicle data allows "quick access" to correct (if improperly input) or change the basic data (stored in the vehicle) for the CBS reset. This includes decreasing the use percentage and number of resets when a reset was mistakenly performed. When the CBS reset is carried out, the changed data in the tester is automatically transferred to the vehicle.

Scheme 43

1. CBS correction vehicle data selection 1 Correction engine oil Correction microfilter Correction front brakes Correction rear brakes Correction vehicle check
2. CBS correction vehicle data selection 2 Correction spark plugs Correction brake fluid Correction coolant Correction Vehicle State Inspection Correction Emission Inspection
3. CBS correction vehicle data selection 3 Write telephone numbers Correction date of first registration
4. End