Z Series E85 Z4 3.0Si (N52) ROADST
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TCU: Telematics control unit
The emergency call is transmitted via the TCU. The TCU is connected to the crash safety module by the
instrumentation bus (I-bus).
Mechanical components of the safety system:
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Belt force limiters on seat belts
The seat belts are the primary restraint system for all occupants.
To minimise the load on the chest area of the front passengers in the event of a severe head-on collision, the
front seat belts are fitted with belt force limiters as standard. The belt force limiters ensure that the belt strap can
give by ay defined amount if the load exceeds a certain level. The risk of injury due to the belt force acting on the
body is therefore reduced.
System functions
The following safety system functions are described:
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Self-test
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Impact detection
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Triggering of safety system
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Data storage in the case of safety system triggering
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Message to other control units
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Visual and audible seat belt warning
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Emergency call
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Monitoring of battery cable
Self-test
In addition to all the inputs and outputs, the crash safety module also monitors the internal components (self-
test). Possible fault codes are stored in the crash safety module. In the event of a system fault or a component
fault, the airbag warning lamp lights up.
The crash safety module performs a self test after the ignition is switched on. During this time, the airbag
indicator lamp will light up (approximately 3 to 5 seconds). The airbag indicator lamp goes out when the safety
system is operational.
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The airbag indicator lamp come on if the crash safety module receives no CAN message from the
instrument cluster.
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The airbag warning lamp remains on if the crash safety module detects an existing fault or one that has
been stored during the self-test or while the vehicle is in motion.
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If the safety system detects a fault, operability of the safety system is partially maintained, subject to the
following preconditions:
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If a fault is detected in a power circuit of the safety system, only the affected circuit is deactivated. The
other airbags and belt tensioners remain operational.
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If there is a fault in the airbag warning lamp circuit, the lamp does not light up during the self-test. If
there is no other fault, the safety system remains fully operational.
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The entire safety system is deactivated if there is an internal fault in the crash safety module or in the power
supply. (The airbag and seat belt indicator lamps light up, check control symbol in the LCD)
Impact detection
The crash safety module can detect an impact from any angle (360
°
).
SBT Crash safety (ACSM) E60, E61, E63, E64, E70, E85, E93
BMW AG - TIS
18.02.2013 04:36
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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