Scheme 28
Principles of Operation
Some modules must be programmed as part of the repair procedure. If this procedure is not followed the module will not function correctly and may set a number of DTCs, including B2477 or PI639, which indicate that some necessary data has not been programmed into the module.
Note. The vehicle must be stationary and level, with all accessories off, while configuring modules.
Modules that need programming should not be exchanged between vehicles. In most cases the parameter values or settings are unique to that vehicle, and if not set correctly, will cause concerns or faults.
Some programmable parameters, such as belt minder on/off, can be changed from the factory setting at the customer's request.
WDS will automatically attempt to retrieve the module configuration information from all modules, and from a backup location in the powertrain control module (PCM) when vehicle ID is carried out. If the module and the PCM do not contain correct information the diagnostic tool will either request "As Built" data or display a list of items that you will need to manually configure. The diagnostic tool will program the module based on the data you enter.
There are three different methods that are used for module programming
- Programmable module installation (PMI)
- Calibration update
- Programmable parameters
Some modules do not support all three methods.
Vehicle Identification (VID) Block
Some PCMs contain a memory area called a vehicle identification (VID) block. The VID block is used to store backup data for each programmable module, as well as, powertrain configuration information.
If the diagnostic tool cannot retrieve module option content information from the suspect module, the diagnostic tool will attempt to extract backup information from the PCM VID block.
The PCM VID block contains the factory settings for the configurable modules unless the PCM is flashed with a new calibration, in which case some PCM parameters may be modified.
As-Built Data Center
The As-Built Data Center maintains a record of the vehicle configuration in a database. The vehicle VIN is necessary to obtain this information. The As-Built Data Center records the applicable module configurations stored in each module before the vehicle leaves the factory. The As-Built Data Center will always reflect the original build of the vehicle as it left the factory. Only contact the As-Built Data Center when directed to do so by the diagnostic tool.