• Fou r Wh eel Speed Sen sor s/Tone Wh eel a ssem -
blies
• ABS wa r n in g in dica tor
• TCS (ASR) even t in dica t or
• TCS (ASR) wa rn ing in dica t or
• St eer in g An gle Sen sor
• La t er a l Acceler a t ion /Ya w Ra te Sen sor
• Br ake P ressu r e Sen sor
• ESP even t in dica t or
• Br ake F lu id Level swit ch
• Br ake Swit ch (BS)
• Br ake La m p Swit ch (BLS)
• TCS Swit ch (TCSS)
• K - ABS
• CAN C Bu s
• Fu ses, gr ounds, an d wir in g
3.7.1 ABS AND TCS (ASR) INDICATORS
Th is syst em is equ ipped wit h a n ABS wa r nin g
in dica t or, TCS (ASR) wa rn in g in dica t or, a nd TCS
(ASR) even t in dica t or to a ler t t he driver of a
ma lfu n ct ion /even t it h a s detect ed. Th e CAB ca n
requ est t he illu m in a tion of t he ABS wa r nin g in di-
cat or, TCS (ASR) wa rn in g in dica t or, a nd TCS (ASR)
even t in dica tor via CAN C BUS. Th e CAB con tr ols
th e ABS wa r n in g in dica tor by:
• Ligh t s tea dy du r in g a n in it ia l t est a t t h e begin -
nin g of a n ign it ion cycle t o fu n ction a s a bu lb
check
• Ligh t st ea dy wh en a syst em ma lfu nct ion exist s
(DTC)
• Ligh t st ea dy - If you ha ve n ot m et the speed
requ ir ed t o reset /r etest t h e ABS com pon ent s
Th e In st ru m en t Clu st er (IC) cont rols t he in dica-
tor s. Th e In st rum en t Clu st er t ra n sm it s a m essa ge
over t h e CAN C Bu s r ela t in g t o dia gn ost ics a nd
cur r en t la m p st a t us for t h e ABS a nd TCS (ASR)
in dica t or s. Th e CAB ca n con t rol the oper a tion of
TCS wa r nin g an d TCS even t in dica t or s by:
• Bot h ligh t st ea dy with engin e off a nd bot h go out
wit h en gin e r u n n in g
• TCS war n in g in dica tor ligh t s st ea dy wh en a TCS
ma lfu n ct ion exist s
• TCS even t in dica t or will fla sh wh en TCS is in an
act ive even t
3.7.2 CONTROLLER ANTILOCK BRAKE
(CAB)
Th e CAB is m ou nt ed dir ect ly t o t h e H ydr au lic
Con t r ol Un it (H CU ) t ha t inclu des a micr opr ocessor
an d t welve solen oids t h at cont r ol va lves th a t con -
tr ol br ake pr essu re du rin g a n tilock br akin g or t r a c-
tion con tr ol even t s. Th e CAB also h a s cir cuit s th a t
mon it or t h e followin g:
• Dou ble br a ke swit ch ou t pu ts ar e mon itor ed t o
deter m in e whet h er or n ot to pr epa re for possible
ABS br a k in g
• Wh eel Speed Sen sor s ar e mon it ored t o det er m in e
wh en a wh eel is ten din g to lock u p. Th e CAB will
opera t e t h e va lves in t h e H CU to con t rol br a k in g
pr essu re du r in g ABS br a kin g
• Det ect ABS system r ela t ed pr oblem s a n d t a ke
dia gn ost ic a ct ion
• Able t o execu te self-t est s a n d ou t pu t con t r ol com -
mands
Wh en equipped with E lectr on ic St a bilit y (E SP ),
th e CAB a lso mon it or s th e followin g:
• Th e ESP looks a t t h e St eer in g Angle Sen sor valu e
an d m onit ors t h e speed of t he i n ner an d ou ter
wh eels t o en su r e t h a t t h e va lu es a r e pla u sible.
Th e St eer in g An gle Sen sor also m on it or s t h e
speed th at th e steer in g wheel is tur ned.
• Th e La t era l Acceler a t ion /Ya w Ra te Sensor is con-
ta in ed in on e u nit . Th e sensor m ea su res side t o
side (la t er a l) motion a nd r ota t ion a l m ot ion (h ow
fast t h e veh icle is tu r nin g).
• Th e ESP u ses da t a from th e Br ake P ressu r e
Sensor t o an a lyze h ow h a rd an d fa st t h at t h e
driver wan ts to brake.
3.7.3 HYDRAULIC CONTROL UNIT (HCU)
Th e HCU on t he Bosch 5.7 ha s an in tegr al va lve
body for con t rollin g t h e fr on t a nd rea r br akes.
Wit h in t h e H CU ar e in let , ou t let , a n d shu t tle
valve s , to re leas e b rak e p re s s ure as re quire d to
avoid wh eel lock u p, keepin g t h e wh eels rollin g, a nd
ma in t a in opt imu m deceler a tion wit h st abilit y. Th e
Pu m p Mot or is a t ta ch ed t o t he H CU wh ich wor ks
wit h th e ABS an d TCS a nd is con t rolled by th e
CAB. Th e pr im a ry fu n ction is to pr ovide extr a
am ou nt of flu id wh en n eeded.
3.7.4 SWITCHES/SENSORS
BRAKE SWITCH (BS): Th is swit ch pr epa r es t h e
CAB for a possible a nt ilock even t. The CAB u ses an
out pu t st at e volt a ge fr om th e BS wh en t h e br a ke
peda l is eit h er r elea sed/depr essed. Th e Fu sed Ign i-
tion Swit ch Ou t pu t cir cu it su pplies 12 volt s t o th e
BS. A r elea sed br a ke peda l will close th e BS cir cu it
an d t he BS Ou tpu t cir cuit su pplies 12 volt s to t h e
CAB. Wh en t h e dr iver depresses t he br a ke pedal,
th e BS Ou tpu t cir cu it volt a ge dr ops t o 0 volt s a nd
th e CAB sen ses t he br ake peda l st a te. This t ells t he
CAB wh a t posit ion t h e br a ke peda l is cu r ren t ly in to
ma ke an ABS event possible. Wh en u sin g t h e
DRBII I" in In pu ts/Ou t pu ts, t he BS a nd BLS will
3
GEN ERAL I N FORM AT I ON
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