History

History







- In earlier cars each control module handled a particular specific function. Cars with a trip computer required an extra control module to run the trip computer functions. If a problem arose in a control module it was replaced, regardless of whether the fault was a hardware or a software fault.
- As the number of variants and amount of functionality increased, it became both impractical and uneconomic to have one control module per function as before. A new type of electrical system was required. The new electrical system uses distributed functionality, CAN communication and re-programmable control modules.
- Distributed functionality means that a function need not be connected to a particular control module. A single function can be divided between several different control modules.
- An example of this is the lock and alarm system on the S80. The lock and alarm system function is distributed between the central electronic module (CEM), upper electronic module (UEM), driver information module(DIM), driver door module (DDM), passenger door module (PDM) and rear electronic module (REM).
- The controller area network (CAN) is a high speed digital network, which permits the control units in the car to transmit a large amount of information in a very short time.
- Re-programmable control units permit programming of increased functionality, without needing to replace the control module. This decreases the repair costs for the customer.
- Software downloading has a number of advantages:
- To obtain a new function, for example to add a trip computer to a car without a trip computer, a new control stalk is installed and a new car configuration file is downloaded into the central electronic module (CEM). The other control modules in the car use the car configuration file to function in a particular way. The software in the driver information module (DIM), for example, reads off whether the trip computer information is to be displayed or not depending on the car's level of equipment
- Fewer control module variants. A good example is the engine control module (ECM). There are 60 different engine variants, which previously required 60 different replacement parts to be stored in the replacement parts stocks. When downloading software, three different hardware packages manage all the variants
- Market adaptation. The application file for the driver information module (DIM) can be the same for all markets. But other market files can be downloaded, to separate different market requirements
- Language. The language in the combined instrument panel can be changed by downloading different language files to the driver information module (DIM)
- This allows faster introduction of improved functionality
- Time saving when working with a particular type of fault. Previously it was necessary to replace a control module. Now a software upgrade can now be downloaded instead.

NOTE All data is overwritten during a software download. This includes diagnostic trouble codes (DTCs) and frozen values which were stored.

Market, language and local configuration files
- The market, language and local configuration files are different types of data files which contain parameters which guide the software.
- The language file contains information about how the different text messages should be displayed in the text display in the combined instrument panel. There is a language file for each language. This file downloads to the driver information module (DIM).
- The market file contains information about when the service reminder indicator (SRI) should light and all the other market specific settings, such as units in the trip computer and temperature gauges. A number of market parameters, such as trip computers and service reminder indicator (SRI), can also be modified to the customer's requirements. This is carried out via VADIS/VIDA vehicle communication.
- Other market settings, such as fog lamps, cannot be reset because of legal requirements.

NOTE: Customer parameters are only programmed locally in one control module. Certain parameters have already been reprogrammed at the factory.