Content source: http://www.bimmerforums.co.uk
Conditional Based Service (CBS) is an evolution of BMW’s standard service indicator system (SIA) previously fitted across the model range. It was first introduced in 2002 when the ‘new’ 7’ series model was launched and is now a standard feature on most new models.
The concept of CBS was to create a flexible yet economical maintenance schedule for serviceable items fitted to a vehicle. Unlike its predecessor (SIA) which used fixed time and distance service schedules (days and m/km’s)the innovative CBS system goes one step further. This intelligent system constantly gathers information from modules and sensors fitted around the vehicle which allows flexible intervals to be created preventing unnecessary replacement of components which still have substantial service life left. In essence there is an aim to lengthen service intervals and maximise the use of serviceable components.
The type of CBS components supported on a particular model will vary depending on specification and enginetype. Items fall into 2 main groups:
1) Sensor based items
These items are monitored by physical and virtual sensors with some reference being made to variables such as vehicle mileage, driving styles and temperature. Items included in this group are:
2) Internally calculated items
Certain items monitored by the CBS system do not require physical sensors. These serviceable items still operate under fixed intervals with remaining service life calculated by the instrument cluster based on time and distance. Items included in this group are:
The instrument cluster gives advanced notification ofany pending service requirements via informationdisplayed on the LCD. This is displayed in the form on a ‘SERVICE’ warning followed by information relevant to the component requiring maintenance. BMW aim to give approximately four weeks advanced notificationof any maintenance requirements to prevent drivers accidently ‘running over’ service schedules.
Further information can be accessed via the i-Drive system. By navigating through the i-Drive menu into the ‘Service Menu’, it is possible to check the current state and remaining serviceable life of all CBS monitored components. Each item will be highlighted in either Green, Yellow or Red and display a percentage value indicating remaining serviceable life.
Inevitably this extra complexity demands more advanced reset procedures. The first noticeable requirement is the need to set the on-board time and date prior to making any resets. This is taken as the reference point for any ‘time dependant’ CBS items such as ‘Brake fluid’
It is possible to carry out the reset of CBS items manually by following specific procedures relevant to supported vehicles. These procedures will NOT work if:
By using suitable diagnostic equipment connected to the vehicle diagnostic connector it is possible to reset CBS service schedules at any time. By selecting the ‘CBS’ option, the diagnostic equipment will gather information regarding the current state of CBS items from their relevant modules on the CAN network.