V50 T5 AWD L5-2.5L Turbo VIN 67 B5254T7 (2008)
Electrical faults
The communication circuits in the LIN control modules cannot detect electrical faults on the wire. However the master node continuously reads back the
last message it sent itself to check that it has been sent correctly over the LIN bus.
Should the master node discover that the message last read back is incorrect, for example if the signal wire has been short-circuited to voltage or ground,
the master node can set the diagnostic trouble code (DTC) denoting the message has not been sent correctly.
Communication failure
The master node on a LIN bus sends out messages at specific time intervals.
The master node on the LIN bus in question knows which type of response that a particular slave node shall send back for a specific message sent from
the master node. If the master mode does not receive this response, it can set the diagnostic trouble code for failed communication with the slave node in
question.
Faults discovered by slave nodes
Control modules that use LIN communication can have integrated diagnostics exactly as the control modules on CAN. However, it is the Master node to
which the slave node is connected that stores the diagnostic trouble codes for faults that the slave node discovers.
Information about discovered faults in the slave nodes is sent in the messages to the master node.
Each slave node on a LIN bus can be seen as an extension of the master node's own connections. In most cases it is also the master node that makes
evaluations whether the diagnostic trouble code (DTC) can be set or not.
Software downloading
The control modules used as slave nodes on Volvo's LIN buses are supplied preconfigured and with that programmed for a specific behavior.
Volvo does not use software downloading via LIN. However a new configuration file for a LIN bus can be downloaded to the master node that controls
communication on a LIN bus, on condition that the master mode is connected to the vehicle's CAN network.
Accordingly, new slave nodes can be added to an existing LIN bus.
