1997 ACURA NSX Service Repair Manual

Troubleshooting Precaution s
EPS Indicato r Ligh t
Unde r norma l conditions , th e EP S indicato r i n th e gaug e assembl y come s o n whe n th e ignitio n switc h is turne d t o th e O N
(II ) position , the n goe s of f afte r th e engin e i s started . Thi s indicate s tha t th e bul b an d it s circuit s ar e operatin g correctly . I f
ther e i s an y troubl e i n th e system , th e EP S indicato r turn s o n durin g driving , an d th e powe r steerin g assis t i s turne d off .
Whe n th e EP S indicato r come s on , th e contro l uni t memorize s th e DTC . I n thi s case , th e contro l uni t doe s no t activat e th e
EP S syste m afte r th e engin e start s agai n bu t i t keep s th e EP S indicato r on .
Whe n a proble m is detected , th e EP S indicato r come s on . Unde r som e conditio n th e indicato r stay s o n unti l th e ignitio n switc h
i s turne d OFF . Unde r othe r conditions , however , th e indicato r goe s of f automaticall y whe n th e syste m return s to normal .
Fo r DTC s 2 3 an d 31 , th e indicato r goe s of f automaticall y whe n th e syste m return s t o normal . Fo r al l othe r codes , th e indicato r
stay s in unti l th e ignitio n switc h is turne d OFF .
Fo r DTC s 2 4 an d 25 , th e EP S indicato r goe s of f whe n th e syste m is O K afte r th e ignitio n switc h is turne d fro m OF F to O N
(ID .
Diagnosti c Troubl e Cod e (DTC )
• Th e lowes t DT C is indicate d first .
• Th e DTC s continu e blinkin g unti l th e ignitio n switc h i s turne d off .
• Th e DTC s ar e erase d fro m th e contro l uni t whe n th e EP S contro l uni t VB U powe r suppl y o r connecto r i s disconnected .
• Th e EP S syste m ca n b e rese t an d th e contro l unit' s memor y ca n b e erase d b y disconnectin g th e CLOC K (7. 5 A ) fus e fo r
mor e tha n te n second s (excep t DTC s 2 4 an d 25) .
Self-diagnosis :
The CP U (centra l processin g unit ) control s th e followin g whe n it detect s a proble m durin g self-diagnosis :
1 . Turn s th e EP S indicato r O N to aler t th e driver .
2 . Powe r assis t stops , an d norma l manua l steerin g operatio n resume s (excep t DT C 33) .
3 . Th e EP S contro l uni t memorize s th e diagnosti c troubl e cod e (DTC) .
4 . Afte r th e DT C is store d in th e contro l unit , th e CP U stop s self-diagnosis .
Troubleshooting :
• Befor e startin g th e troubleshooting , clea r th e DT C b y disconnectin g th e CLOC K (7. 5 A ) fus e fo r te n second s o r more ,
an d test-driv e th e vehicle . Chec k tha t th e sympto m o f th e troubl e appear s again , an d the n troubleshoot . I f th e proble m
i s a n intermitten t problem , th e syste m doe s no t becom e activ e afte r th e engin e start s eve n thoug h th e proble m is
solved .
• Whe n bot h EP S indicato r an d A/ T "D " indicato r com e on , perfor m th e A/ T troubleshootin g first .
• Whe n th e customer' s reporte d proble m canno t b e verifie d i n th e car , as k th e custome r abou t th e condition s whe n th e
EP S indicato r cam e ON , the n test-driv e th e ca r unde r thos e conditions , i f possible . I f th e EP S indicato r doe s no t com e
O N durin g th e test , chec k fo r loos e connection s o r poo r contact s a t th e connector s b y wigglin g th e harness , etc .
• Th e connecto r termina l number s ar e viewe d fro m th e wir e sid e fo r th e femal e terminal s an d fro m th e termina l sid e fo r
th e mal e terminals .
• Afte r th e repair , test-driv e th e ca r an d chec k tha t th e EP S indicato r doe s no t com e O N agai n durin g th e test . (Refe r t o
th e Symptom-to-Syste m Char t fo r diagnosti c period. )
ProCarManuals.com

Symptom-to-System Char t
Diagnosti c Troubl e Cod e (DTC )
• Initia l diagnosis : Performe d righ t afte r th e engin e start s unti l th e EP S indicato r goe s off .
• Regula r diagnosis : Continuousl y performe d (unde r som e conditions ) afte r th e EP S indicato r goe s of f unti l th e engin e stops .
• Individua l part/syste m diagnosis: Diagnoses a specifi c part/syste m unde r it s operatin g conditions .
• CPU : Centra l Processin g Unit .
17-25
ProCarManuals.com

Component Location s
SERVICE CHEC KCONNECTO R (2P ) RIGHT-REA
R WHEE L SENSO R
UNDER-HOO D
FUSE/RELA Y BO X
RIGHT-FRON TWHEEL SENSO R
LEFT-REA RWHEEL SENSO R
UNDER-DAS H FUS E BO X
AB S MODULATO R
CONTROL UNI T
GAUG E ASSEMBL Y
AB S INDICATO R
LEFT-FRON TWHEEL SENSO R
UNDER-HOO D FUSE/RELA Y BO X
ABS(30 A ) FUS E
IG S W (A )(50 A ) FUS E BRAK
E LIGHTS/HOR N
(2 0 A ) FUS E
UNDER-DAS H FUS E BO X
ABS 1 , 4(2 0 A ) FUS E
BACK-U P LIGHT S
(ISA ) FUS E
HEATE R CONTRO L
(15 A) FUSE
ProCarManuals.com

System Descriptio n
Features/Constructio n
When th e brak e peda l i s presse d durin g driving , th e wheel s ca n loc k befor e th e vehicl e come s t o a stop . I n suc h a n event ,
th e maneuverabilit y o f th e vehicl e i s reduce d i f th e fron t wheel s ar e locked , an d th e stabilit y o f th e vehicl e i s reduce d i f th e
rea r wheel s ar e locked , creatin g a n extremel y unstabl e condition . Th e AB S precisel y control s th e sli p rat e o f th e wheel s t o
ensur e maximu m gri p forc e fro m th e tires , an d i t thereb y ensure s maneuverabilit y an d stabilit y o f th e vehicle . Th e AB S
calculate s th e sli p rat e o f th e wheel s base d o n th e vehicl e spee d an d th e whee l speed , the n it control s th e brak e flui d pres -
sur e t o attai n th e targe t sli p rate .
WHEE L
SENSO R
ProCarManuals.com

*1: WithTC S
Terminal sid e o f femal e terminal s
ABS CONTRO L UNI T 25 P CONNECTO R
ABS Contro l Uni t Termina l Arrangemen t
ProCarManuals.com

*1: WithTCSProCarManuals.com

Troubleshooting Precaution s
ABS Indicato r
1. I f th e syste m is OK , th e AB S indicato r come s o n fo r tw o second s (initia l tur n on ) afte r turnin g th e ignitio n switc h O N (II) ,
the n th e AB S indicato r goe s off . Afte r tha t time , th e AB S indicato r come s o n agai n afte r startin g th e engine , the n th e
AB S indicato r goe s of f tw o second s afte r th e ignitio n switc h retur n t o O N (II) . Thi s occur s becaus e th e AB S contro l uni t
activate s b y th e powe r sourc e circui t tha t i s connecte d onl y whe n th e ignitio n switc h is O N (II) .
2 . I f a proble m occurs , th e Centra l Processin g Uni t (CPU ) diagnose s th e proble m are a an d th e proble m condition , the n th e
CP U memorize s th e Diagnosti c Troubl e Cod e (DTC ) an d turn s o n th e AB S indicator . I f th e syste m is OK , th e AB S indicato r
doe s no t com e o n excep t whe n th e ignitio n switc h is initiall y turne d on .
3 . I f th e proble m is detecte d intermittentl y o r continuously , th e AB S indicato r indicatio n patter n i s differen t a s describe d
below .
• DT C 61 o r 62 :
The AB S indicato r come s o n whe n a proble m is detecte d in ever y tim e th e syste m is activated , an d th e AB S indicato r
goe s of f whe n th e syste m return s t o normal .
• DT C 11 , 13 , 15 , 17 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 54 , 7 1 o r 81 :
The AB S indicato r come s o n whe n a proble m is detecte d in ever y tim e th e syste m is activated , an d th e AB S indicato r
continue s o n unti l th e ignitio n switc h is turne d OF F regardles s o f th e syste m return s t o norma l o r not .
• DT C 12 , 14 , 16 , 18 , 21 , 22 , 23 , 24 , 41 , 42 , 43 , 44 , 51 , 5 2 o r 53 :
The AB S indicato r come s o n whe n a proble m is detected , an d th e AB S indicato r continue s o n unti l th e ignitio n switc h
i s turne d OFF . Th e AB S indicato r goe s of f whe n th e syste m is activate d th e nex t time .
4 . Th e AB S indicato r come s o n whe n th e AB S contro l uni t detect s a proble m in th e system . However , eve n thoug h th e
syste m is operatin g properly , th e AB S indicato r wil l com e on , unde r th e followin g conditions . T o determin e th e actua l
caus e o f problem , questio n th e custome r abou t th e problem , takin g thes e condition s int o consideration .
• Onl y driv e whee l (o r wheels ) rotat e
• On e driv e whee l i s stuc k
• Vehicl e spi n
• AB S continuou s operat e fo r a lon g tim e
• Signa l disturbanc e
Diagnosti c Troubl e Cod e (DTC )
1 . I f a proble m occur s i n th e system , th e Centra l Processin g Uni t (CPU ) diagnose s th e proble m are a an d th e proble m
condition , the n th e CP U memorize s th e Diagnosti c Troubl e Cod e (DTC ) int o th e EEPRO M (non-volatil e memory) .
2 . Th e DT C clearin g i s possibl e onl y whe n performin g th e specifie d procedures , an d th e DT C is no t cleare d unde r th e
followin g conditions .
• Turnin g th e ignitio n switc h of f o r disconnectin g th e batter y termina l
• Th e syste m return s t o norma l
3 . Th e memor y ca n hol d an y numbe r o f DTCs . However , whe n th e sam e DT C is detecte d mor e tha n once , th e late r on e is
writte n ove r th e previou s one . Therefore , whe n th e sam e proble m is detecte d repeatedly , i t i s memorize d a s on e DTC .
4 . Th e DTC s ar e indicate d in th e orde r o f ascendin g number , no t i n th e orde r the y occur .
5 . Perfor m th e specifie d procedure s t o indicat e th e DTCs .
Self-diagnosi s
1. Self-diagnosi s can b e classified into tw o categories .
• Initia l diagnosis : Performe d righ t afte r th e engin e start s an d unti l th e AB S indicato r goe s off .
• Regula r diagnosis : Performe d righ t afte r th e initia l diagnosi s an d unti l th e ignitio n switc h i s turne d off .
2 . Whe n a proble m is detecte d b y self-diagnosis , th e syste m
• Turn s th e AB S indicato r O N
• Memorize s th e DT C
• Stop s AB S contro l
ProCarManuals.com

Kickback

1. The motor operates when the ABS is functioning, and the fluid in the reservoir is forced out to the master cylinder,

causing kickback at the brake pedal.

Pump Motor

1. The pump motor operates when the ABS is functioning.

2. The ABS control unit checks the pump motor operation during initial diagnosis when the vehicle is started. You may

hear the motor operate at this time, but it is normal.

Brake Fluid Replacement/Air Bleeding

1. Brake fluid replacement and air bleeding procedures are the same as vehicles without ABS. To ease bleeding, start

with the front wheels.

Troubleshooting

1. The troubleshooting flowcharts procedures assume that the cause of the problem is still present and the ABS indicator

is still on. Following the flowchart when the ABS indicator does not come on can result in incorrect diagnosis.

2. Question the customer about the conditions when the problem occurred, and try to reproduce the same conditions

for troubleshooting.

Find out when the ABS indicator came on, such as during initial diagnosis, during ABS control, after ABS control,

when vehicle speed was at a certain speed, etc.

3. When the ABS indicator does not come on during the test-drive, but troubleshooting is performed based on the DTC,

check for loose connectors, poor contact at the terminals, etc. before you start troubleshooting.

4. After troubleshooting, erase the DTC and test-drive the vehicle. Be sure the ABS indicator does not come on.

5. The connector illustrations show the female terminals with a single outline and the male terminals with a double outline.

ABS Function Test

To simulate ABS operation and activate the solenoid valves and pump, use the Honda PGM Tester.

Connect the PGM Tester to the 16P Data Link Connector (DLC). When the System Select menu is displayed, select the ABS

Test Mode menu and follow the tester's prompts.ProCarManuals.com