BMW 325Ci Owner's Manual page 192

Tire Pressure C ontrol*
1 9 2 n
T his syst e m re g ularly c h e c k s tire pre s -
s ure a n d m o nitors all fo ur tire s e v e n
w hile drivin g, s o y o u d o n ot h a v e to.
B e hin d th e v alv e st e m in e v ery w h e el,
th ere is a n e xt e n d e d -life ele ctro nic c hip
th at c o ntain s a pre ss ure s e n s or, a
tra n s mitt er a n d a b att ery. T h e pre ss ure
is m e a s ure d in e xtre m ely s h ort tim e
int erv als a n d th e n tra n s mitt e d b y a
ra dio sig n al. If a n irre g ularity is
d e t e ct e d , th e tra n s missio n rat e is
in cre a s e d .
L o c at e d n e ar e a c h w h e el a n d
e m b e d d e d in th e v e hicle b o d y is a n
a nt e n n a th at re c eiv e s sig n als fro m th e
w h e el. A c e ntral ele ctro nic s syst e m
e v alu at e s th e q u a dru ple sig n als a n d
for w ard s a n y c h a n g e s.
T h e R D C pro vid e s a n im p orta nt c o ntri-
b utio n to drivin g s afe ty .
Self- diagnostics
A ll of th e im p orta nt ele ctric al a n d ele c -
tro nic syste m s in th e ve hicle are te ste d
re g ularly a n d a uto m atic ally – th e driver
d o e s n ot h ave to p erform a ny e xtra
o p eratio n s or a dju stm e nts.
Th e in dic ator la m p s c o m e o n brie fly
after th e ig nitio n h a s b e e n turn e d o n, for
e xa m ple.
W hile yo u are drivin g, th e fu n ctio n al
statu s of th e a ctu ator m otors (for th e
w in d s hield w ip ers, p o w er w in d o w s,
s e ats, e tc.) is c o n sta ntly b ein g a n aly z e d
by ele ctric al m e a s ure m e nts in th e relays.
In th e s a m e m a n n er, th e ele ctric al
re sista n c e of th e airb a g ig nitio n g e n era -
tors a n d all of th e re m ainin g airb a g
c o m p o n e nts is m e a s ure d at all tim e s. A ny
fa ult in this syste m w o uld b e d e te cte d
im m e diately by a c urre nt flu ctu atio n th at
w o uld n e c e s s arily a c c o m p a ny it. Th e fa ult
w o uld b e in dic ate d im m e diately by th e
airb a g w arnin g la m p.
E ve n after yo u s h ut off th e e n gin e, th e
overall fu n ctio n al statu s of yo ur ve hicle is
m o nitore d . F or e xa m ple, all of th e fla p s of
th e h e atin g a n d ve ntilatio n syste m travel
to th e n e are st limit p o sitio n. This a ctio n
e n s ure s th at th e syste m w ill b e a ble to
provid e d efro stin g, re g ardle ss of oth er
circ u m sta n c e s, e. g. if a m alfu n ctio n in th e
air c o n ditio n er/ a uto m atic clim ate c o ntrol
*
syste m s h o uld o c c ur d urin g th e nig ht
w hile th e ve hicle is p ark e d .
A c alibratio n cycle ru n s every te nth tim e
th e e n gin e is s h ut off. D urin g this cycle,
th e a ctu ator m otors of all th e h e atin g a n d
ve ntilatio n fla p s travel to th eir limit sto p s
in b oth dire ctio n s. Th e limit p o sitio n s a n d
th e re turn travel p ath s are c h e c k e d in this
m a n n er in ord er to e n s ure th at a p pro -
priate a dju stm e nts for th e o p eratin g
ele m e nts c a n b e m a d e at a ny tim e.
Yo u w ill h e ar th e s o u n d s of th e air fla p s a s
th e air c o n ditio n er/ a uto m atic clim ate
*
c o ntrol c arrie s o ut its s elf- dia g n o stic
fu n ctio n s after th e ig nitio n h a s b e e n s h ut
off. A ll of th e oth er s elf- dia g n o stic s fu n c -
tio n s o p erate sile ntly in th e b a c k gro u n d .
A ny p o ssible fa ults d e te cte d d urin g th e s e
s elf- dia g n o stic s c a n b e re a d o ut a n d
c orre cte d by yo ur B M W c e nter d urin g th e
n e xt re g ularly s c h e d ule d m aint e n a n c e .