1997 ACURA NSX Service Repair Manual

ECMSee sectio n 11
VEHICL E SPEE D SENSO R (VSS )
Test , pag e 23-13 1
ProCarManuals.com

Cruise Contro l
Descriptio n
The cruis e contro l syste m use s mechanicall y an d electri -
call y operate d device s t o maintai n vehicl e spee d a t a
settin g selecte d b y th e driver .
Th e EC M receive s comman d signals from th e cruis e con -
trol mai n switc h an d th e cruis e contro l set/resum e switch.
I t receive s informatio n abou t operatin g condition s fro m
th e brak e switch , vehicl e spee d senso r (VSS) , th e clutc h
switch (wit h manua l transmission) , o r th e A/ T gea r posi -
tio n switc h (wit h automati c transmission) . Th e EC M
send s operationa l signal s t o th e device s tha t regulat e th e
throttl e position . Th e throttl e positio n maintain s th e
selecte d vehicl e speed . Essentially , th e EC M compare s
th e actua l spee d of the vehicl e t o th e selecte d speed .
Then , i t use s th e resul t of tha t compariso n t o ope n o r
clos e th e throttle .
Th e brak e switc h release s th e system' s contro l o f th e
throttl e a t th e instan t th e drive r depresse s th e brak e
pedal . Th e switc h send s a n electroni c signa l t o th e EC M
whe n th e brak e peda l i s depressed ; th e EC M respond s
b y allowin g th e throttl e t o close . Th e clutc h switc h (man -
ual transmission ) o r th e A/ T gea r positio n switc h (auto -
mati c transmission ) send s a disengag e signa l t o th e
EC M tha t als o allow s th e throttl e t o close . Operation
:
Th e cruis e contro l syste m wil l se t an d automaticall y
maintai n an y spee d abov e 2 5 mp h (4 5 km/h) . T o set ,
mak e sur e tha t th e mai n switc h i s i n th e "ON " position .
Afte r reachin g th e desire d speed , pres s th e se t switch .
Th e EC M wil l receiv e a se t signa l and , i n turn , wil l actu -
at e th e throttl e valv e contro l motor . Whe n th e se t switc h
i s depresse d an d th e cruis e contro l syste m is on , th e
"cruis e control " O N indicato r i n th e gaug e assembl y wil l
ligh t up . Yo u ca n cance l th e cruis e contro l syste m b y
pushin g th e mai n switc h t o "OFF" . Thi s erase s th e se t
spee d fro m memory . I f th e syste m is disengage d tem -
poraril y b y th e brak e switch , clutc h switch , o r A/ T gea r
positio n switc h an d vehicl e spee d i s stil l abov e 2 5 mph ,
pres s th e resum e switch . Wit h th e resum e switc h
depresse d an d th e se t memor y retained , th e vehicl e
automaticall y return s t o th e previou s se t speed .
Fo r gradua l acceleratio n withou t depressin g th e acceler -
ato r pedal , pus h th e resum e switc h dow n an d hol d i t
ther e unti l th e desire d spee d i s reached . Thi s wil l sen d
a n acceleratio n signa l t o th e ECM . Whe n th e switc h i s
released , th e syste m wil l b e reprogramme d fo r th e ne w
speed . T o slo w down , depres s th e se t switch . Thi s wil l
sen d a deceleratio n signa l t o th e EC M causin g th e ca r t o
coas t unti l th e desire d spee d i s reached . Whe n th e
desire d spee d i s reached , releas e th e se t switch . Thi s
wil l reprogra m th e syste m fo r th e ne w speed .
ProCarManuals.com

Cruise Contro l
Troubleshootin g
NOTE:
Th e number s i n th e tabl e sho w th e troubleshootin g sequence .
Befor e troubleshooting :
— Chec k th e No . 5 (1 5 A ) fus e i n th e under-das h fus e box , an d th e No . 2 9 (5 0 A ) an d No . 4 5 (2 0 A ) fuse s i n th e under -
hoo d fuse/rela y box .
— Chec k tha t th e horn s sound .
— Mak e sur e tha t th e headlight s g o off .
ProCarManuals.com

Control Uni t Inpu t Tes t
SRS component s ar e locate d i n thi s area . Revie w th e
SR S componen t locations , precautions , an d procedure s
i n th e SR S sectio n 24 befor e performin g repair s o r ser -
vice .
Remov e th e bulkhea d panel , the n disconnec t th e con -
nector s fro m th e EC M an d mak e th e followin g tests .
Inspec t th e connecto r an d socke t terminal s t o b e sur e
the y ar e al l makin g goo d contact .
I f th e terminal s ar e bent , loose , o r corroded , repai r
the m a s necessary , an d recheck the system .
I f th e terminal s loo k OK , mak e th e followin g inpu t
test s a t th e connector .
— If an y tes t indicate s a problem , fin d an d correc t
th e cause , the n rechec k th e system .
— If al l th e inpu t test s prov e OK , th e EC M mus t b e
faulty ; replac e it .
ProCarManuals.com

Cruise Contro l
Control Uni t Inpu t Tes t (cont'd )
WireTes t conditio n Test: Desire d resul t Possible caus e if resul t i s no t obtaine d
BLKUnde r al l condition sCheck fo r continuit y t o ground :
Ther e shoul d b e continuity . •
Poo r groun d (G101 )
• A n ope n i n th e wir e
YEL/BL KIgnition switc h O N (II )Chec k fo r voltag e t o ground :
Ther e shoul d b e batter y voltage . •
Blow n No . 1 8 (2 0 A ) fus e
• A n ope n i n th e wir e
LTGR N
Ignition switc h O N (II )
an d contro l switc h O N Chec
k fo r voltag e t o ground :
Ther e shoul d b e batter y voltage . •
Blow n No . 5 (1 5 A ) fus e
• Fault y contro l switc h
• A n ope n i n th e wir e
LT GRN /
BLKRESUM E butto n pushe d
LT GRN /
RED
SET butto n pushe d
Groun d eac h terminal :
Horn s shoul d soun d a s th e switc h i s
pushed . •
Blow n No . 4 5 (2 0 A ) fus e
• Fault y SET/RESUM E switc h
• Fault y cabl e ree l
• A n ope n i n th e wir e
BLU/OR N
M/T: Clutc h peda l
release d
A/T: Shif t leve r i n
o r
Chec k fo r continuit y t o ground :
Ther e shoul d b e continuity . •
Fault y o r misadjuste d clutc h switc h
(M/T)
• Fault y A/ T gea r positio n switc h (A/T )
• Poo r groun d (G401 , G402 , G403 )
• A n ope n i n th e wir e
ORN
Ignitio n switc h O N (II )
an d mai n switc h ON ;
raise th e rea r o f th e car ,
and rotat e on e whee l
slowly . Chec
k fo r voltag e betwee n th e
YEL/RE D an d BL K terminals :
Ther e shoul d b e 0 - 5 V or mor e -
0 - 5 V or mor e repeatedly . •
Fault y vehicl e spee d senso r (VSS )
• A n ope n i n th e wir e
GRY
Ignitio n switc h O N (II) ,
mai n switc h ON ; brak e
peda l pushed , the n
release d
Check fo r voltag e t o ground :
Ther e shoul d b e 0 V wit h th e peda l
pushe d an d batter y voltag e wit h th e
peda l released . •
Fault y brak e switc h
• A n ope n i n th e wir e
GRN/WH T
Brake peda l pushed ,
the n release d Chec
k fo r voltag e t o ground :
Ther e shoul d b e batter y voltag e wit h
th e peda l pushed , an d 0 V wit h th e
peda l released . •
Fault y brak e switc h
• A n ope n i n th e wir e
Ignitio n switc h O N (II )
BLU/BL K
Attach t o ground : Th e indicato r ligh t
i n th e gaug e assembl y shoul d com e
on.
• Blow n bul b
• Blow n No . 5 (1 5 A ) fus e
• Fault y dimmin g circui t i n th e gaug e
assembl y
• A n ope n i n th e wir e
ProCarManuals.com

Main Switc h Replacemen t
SRS component s ar e locate d i n thi s area . Revie w th e
SR S componen t locations , precautions , an d procedure s
i n th e SR S sectio n 24 befor e performin g repair s o r ser -
vice .
1. Remov e th e dashboar d lowe r cover , an d disconnec t
th e connectors .
2 . Remov e th e dashboar d lowe r pad .
DASHBOAR D LOWE R
COVE R
DASHBOARD LOWE R
PAD
3. Remov e the tilt cover .
TILT COVE R
4. Remov e th e steerin g colum n covers .
NOTE : B e carefu l no t t o damag e th e steerin g col -
um n covers .
UPPER COVE R
LOWE R COVE R
(cont'd)
ProCarManuals.com

Main Switch Replacement (cont'd)
Cruise Control

5. Disconnect the 20P, 4P and 5P connectors from the

floor wire harness.

CAUTION: Be careful not to damage the SRS wire

harness.

6. Remove the six screws, then remove the windshield

wiper-cruise control switch assembly.

7. If necessary, replace the cruise control switch bulbs.ProCarManuals.com

Cruise Contro l
Main Switc h Tes t
1. Remov e th e dashboar d lowe r cove r (se e page
23-307 ).
2 . I f necessary , remov e th e dashboar d lowe r pad .
3 . Disconnec t th e 20 P connector , an d chec k fo r conti -
nuit y betwee n th e terminals , i n eac h switc h posi -
tion , accordin g t o th e table .
ProCarManuals.com