Introduction, Network
Introduction, network
Compared to the X70 the P2X has a more developed network which covers most functions in the car.
The electrical system is based on a network with a number of modules. The data is digitally transferred, between the modules, via the usual twinned cables (twisted pair).
The communication method is multiplex and the communication protocol is VOLCANO. (VOLCANO is a further development of CAN and operates with real time operation and prioritizing).
The power supply to the modules occurs in the normal way using the usual cables.
Transmitters (sensors, switches etc) are connected directly to the modules via the usual cables.
Controlled components are connected directly to the modules or via the usual cables. They are controlled by the modules directly or via the relay/ power stages etc.
The electrical system status is continuously monitored. In case of faults/problems, manual deselection of functions etc., the driver is informed via check/warning lamps and text messages in the display.
High and low speed sectors
The network consists of two sectors with different transfer rates.
- The engine compartment sector, which requires fast communication, has a transfer rate of 250 kbps.
- The passenger compartment sector, which does not require such fast communication, has a transfer rate of 125 kbps.
The connection of these two sectors is provided by the Central Electronic Module which converts the communication between the network sectors up or down.
Diagnostic information via the display in the combined instrument panel
The aim of this function is to increase the quality of repairs and reduce the lead times for fault-tracing/repair and verification after repairs both in the factory and at the dealership.
By using this function one can quickly discover, without connecting an external instrument, whether:
- the car is OK or not.
- which module/s the diagnostic trouble codes (DTCs) are stored in.
- which module/s have not gone through all their diagnostic functions.
For further fault-tracing (reading off codes etc.) VIDA must be connected to the car.
For the function to be initiated the car speed must be 0 km/h (0 mph). When the network is in transport position the function is initiated directly the ignition is switched on.
In normal position the function is initiated by:
- turning the ignition key to position II.
- hold the button ENTER (at the end of the left steering wheel stalk) pressed in at the same time as the switch for the rear fog lamps is pressed in twice within two seconds.
The function is automatically interrupted:
- when all messages are read off and acknowledged (press ENTER to acknowledge and scroll to the next message).
- if the start key is turned to position I or 0.
When the function is initiated the following occurs:
- Central Electrical Module requests status information from the master modules.
- if necessary the Central Electrical Module reads off the configuration to determine which modules are included. (requirement = reply missing from a module).
- Central Electrical Module reads information and sends a message to the DIM which displays it.
Diagnostic texts which can be displayed in the display
The current status is always displayed in the first row of the display - if the diagnostic trouble codes (DTCs) are stored. If a new diagnostic trouble code (DTC) is found there is a sound signal.
Additional information is displayed on the second row, for example XXX NOT CHECKED.
XXX in the table below = three character abbreviation for the affected module, for example Rear Electronic Module (REM).
