Audi A5 - Page 32

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Convenience system central control unit
The prerequisite for locking of the steering column
by the electrical steering column lock control unit
J764 is the presence of supply voltage across both
ELV enable lines. To this end, both the onboard
power supply control unit J519 and the conven-
ience system central control unit J393 connect ter-
minal 30 to the corresponding discrete lines for the
duration of locking.
If a "terminal 15" request is issued to the conven-
ience system central control unit J393, then a check
must be made to ensure that steering column has
been successfully unlocked before terminal 15 is
connected.
This happens as follows:
– On receiving a "terminal 15" request, the conven-
ience system control unit J393 queries the elec-
trical steering column lock control unit J764 by a
LIN bus message.
– If the steering column has been successfully
unlocked, control unit J393 is notified via the dis-
crete line "enable terminal 15".
The enable line remains active throughout the
period in which the ELV is unlocked.
– After issuing an enable command, the conven-
ience system central control unit J393 activates
the terminal 15 relay
System overview
393_021
Onboard power
supply control unit
J519
Terminal 30 Terminal 30 Terminal 30
Electrical
steering column
lock control unit
J764
Convenience system
central control unit
J393
Convenience CAN bus
Enable ELV
Enable
Ter m in a l 15
LIN bus
5A
Enable ELV