Volkswagen Passat '97, User Manual

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ABS/EDL
ABS/EDL control unit J104
Features of control unit:
- Redundant computer concept with
separate watchdog,
- Self-diagnosis capability,
- 26-pin connector contact.
Redundant computer concept
In this case, redundant stands for a computer
concept with several backups.
In the control unit there are two computers
which work with the same program
independently and check one another.
The two computers are, in turn, monitored by
a third computer which assumes the task of
controlling the solenoid valve relays.
This third computer is known as the watchdog.
If it detects a fault, it stores the fault message
in a read-only memory and can be read out
during the self-diagnosis. The fault is indicated
by the ABS warning lamp.
SSP 192/064
ABS/EDL control unit