1991 ACURA NSX Service Repair Manual

Speedometer/Trip Meter/Odomete r
Troubleshooting
(From page 23-131 )
Connec t th e Tes t Harnes s (07LA J —PT3020A ) betwee n th e VS S an dthe engin e wir e harness .
Raise th e rea r o f th e car , an d sup -port i t wit h stands .
Back-prob e th e OR N wire , an d
connec t i t t o bod y groun d throug h
a voltmeter .
Pu t th e ca r i n neutra l wit h th e
ignitio n switc h O N (II) .
Slowl y rotat e on e whee l wit h th e
othe r whee l blocked .
Does voltag e puls e fro m 0 toabou t 5 or mor e V ?
Disconnec t th e 30- P connecto r a t
th e speedometer .
Back-probe th e OR N wire , an dconnec t i t t o bod y groun d throug h
a voltmeter .
Slowl y rotat e on e whee l wit h th e
othe r whee l blocked .
Does th e voltmete r indicat e
pulsin g voltage ?
WHT TES T HARNES SCLIP
TES T HARNES S07LAJ - PT3020 ARED TES T HARNES SCLIP
PROTECTIV ETAPE
VSSGR N TES T HARNES S CLI P
Replac e th e VS S (se e pag e
23-133 ).
Repai r ope n i n th e OR N wire ,
betwee n th e VS S an d th e
speedometer .
Replace th e speedometer .
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Vehicle Speed Sensor (VSS)

Replacement

1. Disconnect the 3-P connector from the vehicle speed

sensor (VSS).

3-P CONNECTOR

MOUNTING BOLTS

2. Remove the mounting bolts and the VSS, then take

out the VSS assembly.

NOTE: The VSS drive link is a very small part, be

careful not to lose it.

3. Install in the reverse order of removal.
COVER

VSS

DRIVE LINKProCarManuals.com

Fuel Gaug e
Gauge Tes t
1. Befor e testing , chec k th e No . 5 (1 5 A ) fus e i n th e
under-das h fus e box .
2 . Remov e th e rea r bulkhea d pane l behin d th e driver' s
seat , the n remov e th e acces s panel .
3 . Disconnec t th e 3- P connecto r fro m th e fue l gaug e
sendin g unit .
ACCES S PANE L
4. Connec t th e voltmete r positiv e prob e t o th e B
(YEL/WHT ) termina l an d th e negativ e prob e t o th e
C (BLK ) terminal , the n tur n th e ignitio n switc h O N
(II) . Ther e shoul d b e betwee n 5 an d 8 V .
• I f th e voltag e i s a s specified , g o t o ste p 5 .
• I f th e voltag e i s no t as specified , chec k for :
- A n ope n i n th e YEL , YEL/WH T o r BL K wire .
- Poo r groun d (G403) .
5 . Tur n th e ignitio n switc h OFF . Connec t a jumpe r wir e
betwee n th e B (YEL/WHT ) an d A (BLK ) terminals .
CAUTION : D o no t appl y batter y voltag e to th e ter -
minals ; i t wil l damag e th e fue l gauge .
6. Tur n th e ignitio n switc h O N (II) . Chec k tha t th e
pointe r o f th e fue l gaug e start s movin g towar d th e
"F " mark .
CAUTION : Tur n th e ignitio n switc h OF F befor e th e
pointe r reache s th e "F " mar k o n th e gaug e dial ; i f
yo u don't , yo u ma y caus e damag e to th e fue l gauge .
• I f th e pointe r o f th e fue l gaug e doe s no t mov e a t
all , replac e th e gauge .
• I f th e fue l gaug e i s OK , chec k th e sendin g unit .
23-13 4
3-P CONNECTO R
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Sending Unit Test

Do not smoke while working on the fuel

system. Keep open flame away from work area.

1. Remove the rear bulkhead panel behind the driver's

seat, then remove the access panel.

2. With the ignition switch OFF, disconnect the 3-P

connector from the fuel gauge sending unit.

3. Remove the five nuts, then take the fuel gauge send-

ing unit assembly out of the fuel tank.

FUEL GAUGE SENDING

UNIT ASSEMBLY

NUT
4. Measure the resistance between the A and B termi-

nals by moving the float to the heights listed for E

(EMPTY), 1/2 (HALF FULL) and F (FULL).

(Bottom of the fuel tank)

5. If unable to obtain the above readings, replace the

fuel gauge sending unit.ProCarManuals.com

Engine Coolan t Temperatur e (ECT ) Gaug e
ECT Gaug e Tes t
1. Befor e testing , chec k th e No . 5 (1 5 A ) fus e i n th e
under-das h fus e box .
2 . Mak e sur e th e ignitio n switc h i s OFF , the n discon -
nec t th e YEL/GR N wir e fro m th e EC T sendin g uni t
an d groun d i t wit h a jumpe r wire .
YEL/GR NWIRE
ECT SENDIN G
UNI T
3. Tur n th e ignitio n switc h O N (II) .
Chec k tha t th e pointe r o f th e EC T gaug e start s mov -
in g towar d th e "H " mark .
CAUTION : Tur n th e ignitio n switc h OF F befor e th e
pointe r reache s th e "H " mar k o n th e gaug e dial ; i f
yo u don't , yo u ma y damag e th e gauge .
• I f th e pointe r o f th e gaug e doe s no t swin g a t all ,
chec k for :
— A n ope n in th e YE L o r YEL/GR N wire .
— Replac e th e EC T gaug e if th e fus e an d wirin g
is OK .
• I f th e EC T gaug e is OK , chec k th e sendin g unit .
ECT Sendin g Uni t Tes t
1. Disconnec t the YEL/GR N wire fro m the sendin g unit,
and wit h th e engin e cold , us e a n ohmmete r t o meas -
ure resistanc e betwee n th e positiv e termina l an d th e
engin e (ground) .
2 . Chec k th e temperatur e o f th e coolant .
3 . Ru n th e engine , an d measur e th e chang e i n resis -
tanc e wit h th e engin e a t operatin g temperatur e
(radiato r fa n come s on) .
4 . I f th e reading s yo u ge t ar e substantiall y differen t
fro m th e specification s above , replac e th e EC T send -
ing unit .
YEL/GR NWIRE
POSITIV E
• TERMINA L
EC T SENDIN G
UNI T
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Engine Oi l Pressur e Gaug e
Gauge Tes t
1. Befor e testing , chec k th e No . 5 (1 5 A ) fus e i n th e
under-das h fus e box .
2 . Mak e sur e th e ignitio n switc h i s OFF , the n discon -
nec t th e 2- P connecto r fro m th e engin e oi l pressur e
sending unit , an d groun d it wit h a jumpe r wire .
BLU/WH T WIR E
ENGIN E OI L PRESSUR EGAUGE SENDIN G UNI T
3. Tur n th e ignitio n switc h O N (II) .
Chec k tha t th e pointe r o f th e engin e oi l pressur e
gaug e start s movin g towar d th e "8 " mark .
CAUTION : Tur n th e ignitio n switc h OF F befor e th e
pointe r reache s th e "8 " mar k o n th e gaug e dial ; i f
yo u don't , yo u ma y caus e damag e t o th e gauge .
• I f th e pointe r o f th e gaug e doe s no t mov e a t all ,
chec k for :
- A n ope n i n th e YE L o r BLU/WH T wire .
— Replac e th e engin e oi l pressur e gaug e i f th e
wirin g is OK .
• I f th e engin e oi l pressur e gaug e i s OK , g o o n t o
ste p 4 .
4 . Chec k th e engin e oi l pressur e (se e sectio n 8 ).
• I f th e engin e oi l pressur e i s OK , replac e th e en -
gin e oi l pressur e sendin g unit .
Engin e Oi l Pressur e
Warnin g Syste m
Engine Oi l Pressur e Switc h Tes t
1. Rais e th e car , an d plac e safet y stand s in th e prope r
location s (se e sectio n 1 ).
2 . Remov e th e righ t rea r tire .
3 . Remov e th e YEL/RE D wir e fro m th e engin e oi l pres -
sur e switch .
ENGINE OI L PRESSUR E SWITC H
CRANKSHAF TPULLEY
4. Chec k continuit y betwee n th e positiv e termina l an d
engin e (ground ) wit h th e engin e off .
• I f ther e i s n o continuity , th e switc h i s OK .
• I f ther e i s continuity , d o no t replac e th e switch ;
firs t chec k othe r possibl e cause s i n ste p 6 .
6 . Mak e sur e engin e oi l leve l i s OK , the n chec k engine
oi l pressur e (se e sectio n 8 ).
• I f engin e oi l pressur e is OK , replac e th e engin e oi l
pressur e switch .
• I f oi l pressur e i s low , remove , inspect , and , i f
necessary , replac e th e oi l pum p (se e sectio n 8 ).
YEL/RE DWIRE
POSITIV E TERMINA L
OIL FILTE R
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Brake Warnin g Syste m
Parking Brak e Switc h Tes t
1. Remov e th e cente r console , an d disconnec t th e con -
necto r fro m th e switch .
2. Chec k continuit y betwee n th e positiv e termina l an d
bod y groun d wit h th e brak e leve r u p an d down .
• Ther e shoul d b e n o continuit y wit h th e brak e leve r
down .
• Ther e shoul d b e continuit y wit h th e brak e leve r
up.
DOW N
BRAK E LEVE R
POSITIV E TERMINA L
BODY GROUN D
NOTE: (Canada )
I f th e parkin g brak e switc h i s OK , bu t th e brak e
warnin g syste m doe s no t work , mak e th e inpu t
test fo r th e daytim e runnin g light s contro l uni t
(see pag e 23-180 ).
Brak e Flui d Leve l Switc h Tes t
1. Remov e th e reservoi r cap . Chec k tha t th e floa t
move s u p an d dow n freely ; i f i t doesn't , replac e th e
reservoi r ca p assembly .
RESERVOI R CA P
FLOAT
Has a built-i nmagne t
Switch contact s close dwhen floa t drops .
Switc h contact s open , a t
prope r flui d level .
2. Chec k fo r continuit y betwee n th e terminal s wit h th e
floa t u p an d down .
There shoul d b e continuit y wit h th e floa t dow n an d
no continuit y wit h th e floa t up ; i f continuit y is incor -
rect, replac e th e reservoi r ca p assembly .
UP POSITIO N
DOWN POSITIO N
UP
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Seat Bel t Reminde r Syste m
Seat Bel t Switc h Tes t
1. Slid e th e driver' s sea t al l th e wa y forward , the n dis -
connec t th e 2- P connecto r fro m th e sea t bel t switch .
2 . Chec k continuit y betwee n th e A an d B terminal s wit h
th e driver' s sea t bel t buckle d an d unbuckled .
• Ther e shoul d b e n o continuit y wit h th e driver' s
sea t bel t buckled .
• Ther e shoul d b e continuit y wit h th e sea t bel t un -
buckled .
CENTERBUCKL E
DRIVER' S SEA T
View fro m wir e sid e
Low Fue l Indicato r
Indicator Ligh t Tes t
1. Par k th e ca r o n leve l ground .
D o no t smok e whil e workin g o n th e
fue l system . Kee p ope n flam e awa y fro m th e wor k
area. Drai n fue l onl y int o a n approve d container .
2. Remov e th e drai n bol t fro m th e fue l tank , an d drai n
th e fue l int o a n approve d container .
The n instal l th e drai n bol t wit h a ne w washer .
3. Ad d les s tha n 1 1 (2. 9 U.S . Gal , 2. 4 Imp . Gal ) o f
fue l an d tur n th e ignitio n switc h on . Th e lo w fue l in -
dicato r ligh t shoul d com e o n withi n fou r minutes .
• I f i t does , g o t o ste p 4 .
• I f i t doesn't , g o t o ste p 5 .
4. Ad d 4 o f fue l (1. 1 U.S . Gal , 0.8 8 Imp . Gal) . Th e
ligh t shoul d g o of f withi n fou r minutes .
5 . I f th e ligh t di d no t com e o n i n ste p 3 , remov e th e
rea r bulkhea d pane l behin d th e driver' s seat , the n re -
mov e th e acces s panel , an d disconnec t th e 3- P con -
necto r fro m th e fue l gaug e sendin g unit . Connec t th e
A (BLK ) termina l t o th e C (YEL/BLU ) termina l wit h
a jumpe r wire .
• I f th e ligh t come s on , th e proble m is eithe r th e
sendin g uni t o r it s ground .
• I f th e ligh t doe s no t com e on , th e proble m is a n
ope n in th e C (YEL/BLU ) wir e to th e gaug e assem -
bly , o r n o powe r t o th e gauge , o r a ba d bulb .
ACCES SPANEL
3-P CONNECTO R
B (YEL/WHT )
A (BLK)C (YEL/BLU )
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