1991 ACURA NSX Service Repair Manual

Wheel Sensor Signal Confirmation
NOTE: Us e th e AL B checke r (mod e 0 ) t o confir m pro -
pe r whee l senso r operation .
1 . Disconnec t th e 6- P inspectio n connecto r fro m th e
connecto r cove r locate d unde r th e glov e box , an d
connec t th e 6- P inspectio n connecto r t o th e AL B
checker .
07HAJ-SG0010 Bsee pag e 19- 2 fo r othe r applicabl e checkers .
2. Rais e th e ca r s o tha t al l fou r wheel s ar e of f th e
ground , an d suppor t i t o n safet y stand s (se e pag e
1-9 throug h 1-11 ).
3 . Tur n th e ignitio n switc h O N (II) .
4. Tur n th e Mod e Selecto r switc h t o "0" . 5
. Wit h th e transmissio n in neutral , rotat e eac h whee l
briskl y (on e revolutio n pe r second ) b y hand , an d
confir m tha t it s respectiv e monito r ligh t o n th e
checke r blink s a s th e whee l rotates .
NOTE:
• Rotatin g a whee l to o slowl y wil l produc e onl y a
wea k blin k o f it s monito r ligh t tha t ma y b e dif -
ficul t t o see .
• I n brigh t sunlight , th e monito r ligh t ma y b e dif -
ficul t t o see . Perfor m test s i n a shade d area .
• I n som e instances , i t ma y no t b e possibl e to spi n
th e rea r wheel s fas t enoug h t o ge t a monito r in -
dication , i f necessary , star t th e engin e an d slow -
l y accelerat e an d decelerat e th e rea r wheels .
Th e monito r light s shoul d blin k indicatin g a goo d
whee l senso r signal .
I f an y monito r ligh t fail s t o blink , chec k th e suspecte d
senso r an d pulser , it s ai r ga p an d it s wiring/connectors .
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Troubleshooting
Anti-lock Brak e Syste m (ABS ) Indicato r Ligh t
Temporar y Drivin g Conditions :
1. Th e AB S indicato r ligh t wil l com e o n an d th e AB S
contro l uni t memorize s th e diagnosti c troubl e cod e
(DTC ) unde r certai n conditions .
NOTE : Th e DT C explaine d o n page s 19-46 .
• Th e tire(s ) adhesio n is los t du e to excessiv e cor -
nerin g speed .
DTC: 5, 5-4 , 5-8 .
• Th e vehicl e lose s tractio n whe n startin g fro m a
stuc k conditio n o n a muddy , snowy , o r sand y
road.
DTC: 4-1 , 4-2 , 4-4 , 4-8 .
• Whe n th e parkin g brak e is applie d fo r mor e tha n
3 0 second s whil e th e vehicl e i s bein g driven .
DTC: 2.
• Th e vehicl e is drive n o n extremel y roug h road .
Th e AB S is OK , i f th e AB S indicato r ligh t goe s
of f afte r th e engin e i s restarted .
2 . I f yo u receiv e a customer' s repor t tha t th e AB S in -
dicato r ligh t sometime s come s on , chec k fo r a DTC .
I f a DT C is stored , refe r t o th e appropriat e trouble -
shootin g (se e pag e 19-46 ). I f n o DT C is stored ,
chec k th e syste m usin g th e AL B checke r t o confir m
whethe r ther e is an y troubl e in th e system . Se e pag e
19-41 .
3. Th e AB S indicato r ligh t wil l com e o n an d th e AB S
contro l uni t wil l stor e a DT C whe n ther e i s insuffi -
cien t batter y voltag e t o th e AB S contro l unit . A n
exampl e woul d b e whe n th e batter y is s o wea k tha t
th e ca r mus t b e jump-started . Afte r th e batter y i s
sufficientl y recharged , th e AB S indicato r ligh t wil l
wor k normall y afte r th e engin e i s stoppe d an d
restarted .
However , afte r rechargin g th e battery , th e DT C
mus t b e cleare d fro m th e AB S contro l unit' s
memor y b y disconnectin g th e AB S 2, 3 (20A ) fus e
fo r a t leas t thre e seconds . AB
S Indicato r Ligh t Circuit :
CAUTION : Us e onl y th e digita l multimete r t o
chec k th e system .
1. Th e indicato r ligh t doe s no t g o o n whe n th e ignitio n
switc h i s turne d on .
Chec k th e followin g items . I f the y ar e OK , chec k
th e AB S contro l uni t connectors .
I f no t loos e o r disconnected , instal l a ne w AB S con -
tro l uni t an d recheck :
• Blow n AB S indicato r ligh t bulb .
• Ope n circui t i n YE L wir e betwee n No . 5 (1 5 A )
fus e an d gaug e assembly .
• Ope n circui t i n BLU/WH T wir e betwee n gaug e
assembl y an d AB S contro l unit .
• Loos e componen t groundin g of the AB S contro l
uni t t o th e body .
2 . Th e AB S indicato r ligh t remain s O N afte r th e engin e
i s started , howeve r th e AB S indicato r ligh t doe s no t
blin k an y cod e o r sub-code . Chec k th e followin g
items :
• Loos e o r poo r connectio n of the wir e harnes s a t
th e AB S contro l unit .
• Fault y AB S 2, 3 (20A ) fuse .
• Ope n circui t i n WHT/BL K wir e betwee n AB S 2, 3
(20A ) fus e an d AB S contro l unit .
• Ope n circui t i n YEL/BL K wir e betwee n fus e No .
4 (1 5 A ) an d AB S contro l unit .
• Shor t circui t i n BLU/WH T wir e betwee n gaug e
assembl y an d AB S contro l unit .
• Ope n circui t i n WHT/BL U wir e betwee n alter -
nato r an d AB S contro l unit .
• Loos e componen t groundin g o f th e AB S contro l
uni t t o th e body .
I f th e proble m is no t found , substitut e a known-goo d
AB S contro l uni t an d rechec k whethe r th e AB S in -
dicato r ligh t remain s ON .
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Diagnostic Trouble Code (DTC):

1. Stop the engine.

2. Disconnect the service check connector from the connector cover located under the glove box.

Connect the two terminals of the service check connector with a jumper wire.

3. Turn the ignition switch on, but do not start the engine.

4. Record the blinking frequency of the ABS indicator light.

The blinking frequency indicates the diagnostic trouble code (DTC).

CAUTION: Before starting the engine, disconnect the jumper wire from the service check connector, or else the

Malfunction Indicator Lamp (MIL) will stay on with the engine running.

NOTE:

• The ABS control unit can indicate three DTCs (one, two or three problems).

• If the ABS indicator light does not light, see Troubleshooting of ABS Indicator Light Circuit page 19-44.

• If you miscount the blinking frequency, turn the ignition switch off, then turn on to blink the ABS indicator light

again.

• After the repair is completed, disconnect the ABS 2,3 (20A) fuse for at least three seconds to erase the ABS

control unit's memory. Then turn the ignition key on again and recheck.

• The memory is erased if the connector is disconnected from the ABS control unit or the ABS control unit is re-

moved from the body.

• After recording the main and sub-code (if applicable), refer to the Symptom-to-System Chart.ProCarManuals.com

Troubleshooting
Symptom-to-Syste m Char t
19-47
19-5 0
19-7 1
19-71
19-5 1
19-5 2
19-5 3 19-7
1
19-5 7
19-5
5
19-5 9
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Hydraulic Syste m
Hydrauli c Connection s
CAUTION: D o no t spil l brak e flui d o n th e car ; i t ma y damag e th e paint ; i f brak e flui d doe s contac t th e paint , was h it of f
immediatel y wit h water .
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Hydraulic Syste m
Relievin g Accumulator/Lin e Pressur e
1. Drai n th e brak e flui d fro m th e maste r cylinde r an d modulato r reservoi r thoroughly .
2. Remov e th e re d ca p fro m th e bleede r o n th e to p o f th e powe r unit .
3. Instal l th e specia l too l o n th e bleede r screw , an d tur n it ou t slowl y 90 ° t o collec t high-pressur e flui d int o reservoir .
Turn th e specia l too l ou t on e complet e tur n t o drai n th e brak e flui d thoroughly .
4 . Retighte n th e bleede r scre w an d discar d th e fluid .
5 . Reinstal l th e re d cap .
BLEEDE R T-WRENC H07HAA-SG0010 0or07HAA-SG0010 1
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Modulator/Solenoid Uni t
Index/Torqu e
CAUTION:
• D o no t damag e th e brak e pipe s whe n removin g th e spar e tir e an d modulator/solenoi d unit .
• D o no t spil l brak e flui d o n th e car ; i t ma y damag e th e paint ; i f brak e flui d doe s contac t th e paint , was h it of f immediate -
l y wit h water .
MODULATOR/SOLENOI D UNI TSolenoi d Lea k Test ,page 19-6 4Solenoi d Flushing ,page 19-6 5
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Modulator/Solenoid Uni t
Solenoi d Lea k Tes t
1. Disconnec t th e 6- P inspectio n connecto r (PNK )
fro m th e connecto r cove r locate d unde r th e glov e
box, an d connec t th e 6- P inspectio n connecto r t o
th e AL B checker .
CONNECTO RCOVER
ALB CHECKE R07HAJ-SG0010BSe e pag e 19-2 fo r othe rapplicabl e checkers .
6-P INSPECTIO NCONNECTO R
CAUTION: Plac e th e vehicl e o n leve l groun d wit h
th e wheel s blocked . Pu t th e transmissio n in neutra l
for manua l transmissio n models , o r i n fo r auto -
mati c transmissio n models .
2. Remov e th e modulato r reservoi r filter , the n fil l th e
modulato r reservoi r t o th e MA X leve l line .
NOTE : D o no t reus e aerate d brak e flui d tha t ha s
bee n ble d fro m th e powe r unit .
3. Blee d high-pressur e flui d fro m th e maintenanc e
bleeder with the specia l tool .
BLEEDE R T-WRENC H07HAA-SG0010 1or07HA A-SG0010 0
SOLENOI D UNI T
ACCUMULATOR /PRESSURE SWITC HPOWERUNIT
MAINTENANC EBLEEDER8 x 1.2 5 mm9 N- m (0. 9 kg-m ,6.5 Ib-ft )
4. Star t th e engin e an d releas e th e parkin g brake .
5 . Tur n th e Mod e Selecto r t o 1 , an d pres s th e Star t
Tes t button .
6 . Whil e th e pum p i s running , plac e you r finge r ove r
th e to p o f th e solenoi d retur n tub e in th e modulato r
reservoir.
SOLENOI D RETUR NTUBEFeel fo r brak efluid here .
• I f yo u ca n fee l brak e flui d comin g fro m th e retur n
tube , on e o f th e solenoid s i s leaking . G o t o ste p
7.
• I f yo u can' t fee l brak e flui d comin g fro m th e
retur n tube , th e solenoid s ar e OK .
Reinstal l th e modulato r reservoi r filte r an d refil l
th e reservoi r t o th e MA X leve l line .
7 . Blee d high-pressur e flui d fro m th e maintenanc e
bleede r wit h th e specia l tool .
8 . Repea t step s 5 throug h 7 at mode s 2 to 5 wit h th e
AL B checker .
• I f th e solenoi d leakag e ha s stopped , reinstal l th e
modulato r reservoi r filte r an d refil l th e reservoi r
t o th e MA X leve l line .
• I f yo u ca n fee l brak e flui d comin g fro m th e retur n
tube , on e o f th e solenoid s i s leaking . G o t o
Solenoi d Flushing .
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