sensor ACURA NSX 1997 Service Owners Manual

Evaporator Temperature Sensor
Removal
Give th e evaporato r temperatur e senso r a quarte r turn ,
then pul l ou t t o remov e it .
EVAPORATO RTEMPERATUR E SENSO R
Test
Compar e th e resistanc e readin g betwee n th e terminal s
of th e evaporato r temperatur e senso r wit h specificatio n
shown i n th e followin g graph : I t shoul d b e withi n
specification .
NOTE : Di p th e senso r i n ic e water , an d measur e th e
resistance . The n pou r ho t wate r o n th e sensor , an d
chec k fo r chang e i n resistance .
CAUTION : Th e senso r use s a thermisto r whic h
ca n b e damage d if hig h curren t i s applie d t o it
durin g testing . Therefore , us e a circui t teste r
tha t put s ou t a measurin g curren t o f 1 m A o r
less .
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11. Disconnec t th e connector s fro m al l th e contro l
motors an d sensor s attache d t o th e heater -
evaporato r unit .
1 2 . Remov e th e tw o mountin g bolt s an d tw o nuts , the n
remov e th e heater-evaporato r uni t throug h th e
passenge r door .
CORROSIO N RESISTAN TBOLTHEATER-EVAPORATO R UNIT
NUT S29 N- m (3. 0 kgf-m ,
2 2 Ibf-ft )
6 x 1. 0 m m9.8 N- m (1. 0 kgf-m , 7. 2 Ibf-ft )
13. Instal l th e heater-evaporato r uni t i n th e revers e
orde r of removal , and :
• I f you'r e installin g a ne w evaporator , ad d
refrigeran t oi l (ND-OI L 8 ) se e pag e 22-69 ).
• Replac e O-ring s wit h ne w one s a t eac h fitting ,
and appl y refrigeran t oi l t o them .
NOTE : B e sur e t o us e th e righ t O-ring s fo r
R-134 a t o avoi d leakage .
14. Fil l th e radiato r an d reservoi r tan k wit h th e prope r
engine coolan t mixture . Blee d th e ai r fro m th e cool -
in g syste m (se e sectio n 10 ).
CAUTION : Follo w th e sequenc e describe d in th e ai r
blee d procedure . I f you don't , yo u ma y leav e ai r i n
th e syste m whic h coul d damag e th e engine .
15. I f necessary , adjus t th e heate r valv e cable :
• Se t th e ai r mi x contro l moto r a t COO L positio n
(se e pag e 22-57 ).
• Connec t th e en d o f th e heate r valv e cabl e t o th e
heate r valv e arm .
• Gentl y slid e th e cabl e oute r housin g bac k fro m
the en d enoug h to tak e u p an y slac k in th e cable ,
but no t enoug h t o mak e th e othe r en d mov e th e
ar m o n th e ai r mi x contro l motor . The n sna p th e
clam p dow n ove r th e cabl e housing .
CLAMP
HEATE R VALV EARM
HEATE R VALV ECABLE
16. Tur n th e blowe r on , an d mak e sur e tha t ther e is n o
air leakage .
1 7 . Charg e th e syste m (se e pag e 22-91 ), an d tes t per -
formanc e (se e pag e 22-70 ).
SR S UNI T
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Description ——————————————————\
——————————————————\
———
Ignition Timin g Control :
Th e programme d ignitio n use d i n thi s engin e provide s optimu m contro l o f ignitio n timing . A microcompute r determine s
th e timin g i n respons e t o engin e spee d an d manifol d vacuu m pressure . Th e inpu t signal s ar e transmitte d b y th e crank -
shaf t position/cylinde r positio n (CKP/CYP ) sensor , throttl e positio n (TP ) sensor , EC T sensor , an d MA P sensor . Thi s sys -
tem , no t dependen t o n a governo r o r vacuu m diaphragm , i s capabl e o f settin g lea d angle s wit h complicate d characteristic s
whic h canno t b e provide d b y conventiona l governor s o r diaphragms .
Basi c Contro l
Determinatio n of ignitio n timing/curren t duration :
Th e EC M ha s store d withi n i t th e optimu m basi c ignitio n timin g fo r operatin g condition s base d upo n engin e spee d an d in -
tak e manifol d pressure . Wit h compensatio n b y signal s fro m sensors , th e syste m determine s optimu m timin g fo r ambien t
condition s an d send s voltag e pulse s t o th e ICM .
Compensatio n o f Ignitio n Timing :
Compensatio n Ite m
Idlin g
Compensatio n a t warm-u p
Engin e coolan t
temperatur e compensatio nRelate
d Senso r an d Informatio n
CKP/CY P sensor , MA P senso r
Engin e coolan t temperatur e
(ECT) senso r
ECT senso r Descriptio
n
Ignitio n timin g i s controlle d t o th e targe t spee d
wit h compensatio n accordin g t o th e idlin g speed .
La g angl e i s adjuste d accordin g t o warm-u p con -
dition s t o brin g abou t a goo d balanc e betwee n
operatin g performanc e an d exhaus t ga s level .
Compensatio n fo r lea d angl e a t low coolan t
temperatur e an d la g angl e a t hig h coolan t
temperature .
Contro l a t Star t
Ignitio n timin g is fixe d a t 5 ° BTD C fo r cranking . Th e crankin g is detecte d b y th e CY P senso r (crankin g rpm ) an d starte r signal .
Misfirin g Detectio n
A s par t o f th e OB D II misfirin g detectio n system , eac h o f th e ignitio n coil s ha s a built-i n spar k plu g voltag e sensor . Thi s
senso r detect s th e lon g duratio n hig h voltag e whic h occur s i n cas e o f unfavorabl e combustio n o r misfiring . (Fo r details ,
se e sectio n 11 .)
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Radiator and Condenser Fan Controls

Description

Fan control system:

The cooling fan system is comprised of the radiator fan, condenser fan (left and right), engine compartment fan, radiator

fan low relay, radiator fan high relay, condenser fan relay, engine compartment fan relay, radiator fan resistor, radiator

fan control sensor, A/C pressure switch, fan control unit, climate control unit, and ECM.

The fan control unit controls the operation of the radiator fan and condenser fans.

It uses inputs from the radiator fan control sensor and the A/C pressure switches (A and B) in the A/C system to deter-

mine when the fans should run and at what speed.

Additionally, the temperature switch shuts down the A/C system if the engine coolant temperature (ECT) exceeds

266°F (130°C). If the pressure in the A/C system is higher than normal, pressure switch A closes and the fans will run at

high speed only. See the A/C section for the description and specifications of that function.ProCarManuals.com

Radiator and Condenser Fan Controls

Control Unit Terminals

THROTTLE VALVE CONTROL

MOTOR RELAY

Wire

Terminal Color
Connects to

1

2

3

4

5

6

7

8

9

10

11

12
-

LT GRN

GRY/BLK

BLU/RED

BLK

BRN/BLK

GRN

—

ORN/BLU

BLU/BLK

YEL/BLK

GRN/BLK
Not used

Radiator fan control sensor

Climate control unit

Radiator fan high and engine

compartment fan relays coil

Ground (G401, G402, G403)

A/C triple pressure switch A

Radiator fan control sensor

Not used

Condenser fan relay coil

ECM
(ACS)

IG2 (Power supply)

Radiator fan low relay coil
1. Disconnect the 3P connector from the resistor.

3P CONNECTOR
RADIATOR

FAN

RESISTOR

NOT USED

2. Using an ohmmeter, measure resistance between

the A and B terminals. Replace the resistor if the

resistance is not within specifications.

NOTE: Resistance will vary with the resistor

temperature; specifications are at 68°F (20°C).

Radiator Fan Resistor

Resistance: 0.54—0.66 ohms
Radiator Fan Resistor TestProCarManuals.com

Radiator an d Condense r Fa n Control s
Radiator Fa n Contro l Senso r Tes t
NOTE : Blee d ai r fro m th e coolin g syste m afte r install -
in g th e radiato r fa n contro l senso r (se e sectio n 10 ).
1 . Remov e th e radiato r fa n contro l senso r fro m th e
thermosta t cover .
2 . Suspen d th e radiato r fa n contro l senso r i n a con -
taine r o f coolan t a s shown .
THERMOMETE R
RADIATOR FA N
CONTRO L SENSO R
ENGIN E
3. Hea t th e coolant , an d chec k coolan t temperatur e
wit h a thermomete r (se e tabl e below) .
4 . Measur e th e resistanc e betwee n th e A an d B ter -
minal s accordin g t o th e table .
5 . I f unabl e t o obtai n th e abov e readings , replac e th e
radiato r fa n contro l sensor .
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Vehicle Speed Sensor (VSS)

Replacement

1. Disconnect the 3P connector from the vehicle speed

sensor (VSS).

3P 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.
VSS

DRIVE LINK
COVERProCarManuals.com

Safety Indicato r
Componen t Locatio n Inde x
SRS component s ar e locate d in 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 service .
SAFET Y INDICATO R (I n th e gaug e assembly )
• Removal , pag e 23-12 9
• Troubleshooting , pag e 23-15 4
• Inpu t Test , pag e 23-15 2
ROOF LOC K SWITC H (*1 )
Test , pag e 23-15 6
PASSENGER' S DOO R SWITC H
Test , pag e 23-20 6
HIG H MOUN T BRAK E LIGH T
Test , pag e 23-21 3
CEILIN
G LIGH T
Test , pag e 23-20 3
BRAK E SWITC H
Test , pag e 23-21 3
DRIVER' S DOO R SWITC H
Test , pag e 23-20 6
ROO F HOLDE R SWITC H (*1 )
Test , pag e 23-15 7
ENGIN E COMPARTMEN T LI D SWITC H
Test , pag e 23-32 7 RIGH
T BRAK E LIGH T
FAILUR E SENSO R
Test , pag e 23-15 5
LEF T BRAK E LIGH T
FAILUR E SENSO R
Test , pag e 23-15 5 TRUN
K LATC H SWITC H
Test , pag e 23-20 7
1: NSX- T (ope n top ) onl y
Descriptio n
Safety Indicato r System :
LEDs ar e use d t o indicat e whe n th e trun k lid , engin e compartmen t lid , a door , o r th e roo f i s no t latched , o r whe n a brak e
light i s faulty , o r whe n th e roo f i s no t store d o r improperl y store d i n it s holder . Th e LED s wil l g o o n an d sta y o n fo r abou t
tw o second s afte r th e ignitio n switc h ha s bee n turne d O N (II ) t o sho w tha t th e syste m circui t i s functioning .
Brak e Ligh t Bul b Failur e Indicator :
If al l brak e ligh t bulb s ar e OK , th e indicato r ligh t stay s of f becaus e th e ORN/WH T wir e is grounde d b y th e tw o brak e ligh t
failur e sensor s connecte d i n series . Wit h th e brak e light s off , th e groun d i s provide d throug h th e diode , th e failur e senso r
rela y coils , an d bul b filaments . Wit h th e brak e ligh t on , al l fou r relay s (tw o i n th e lef t sensor , tw o i n th e righ t sensor) , con -
necte d i n series , suppl y ground . I f an y o f th e fou r bulb s i s no t working , th e chai n i s broke n an d th e ORN/WH T wir e i s no t
longe r grounded . Th e indicato r ligh t come s on .
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Wire Tes
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 (G401 , G402 , G403 )
• A n ope n in th e wir e
YELIgnitio n switc h O N (II ) Check 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
• A n ope n i n th e wir e
Brak e peda l pushe d Check fo r continuit y t o ground :
Ther e shoul d b e les s tha n 4 W wit h
th e peda l pushed .
ORN/WH T
• Blow n No . 4 5 (2 0 A ) fus e
• Fault y brak e switc h
• Blow n brak e ligh t bulb s
• Fault y brak e ligh t failur e sensor s
• Poo r groun d (G551 )
• A n ope n in th e ORN/WH T o r
GRN/WH T wir e
BLU
Engin e compartmen t li d
ope n
Chec k fo r continuit y t o ground :
There shoul d b e continuity .
• Fault y engin e compartmen t li d
switc h
• Poo r groun d (G401 , G402 , G403 )
• A n ope n i n th e wir e
Trun k li d ope n
GRN/BL K
Check fo r continuit y t o ground :
Ther e shoul d b e continuity .
NOTE : Befor e testing , remov e th e
No . 3 4 (1 5 A ) fuse . •
Fault y trun k latc h switc h
• Poo r groun d (G551 )
• A n ope n in th e wir e
GRN/BL UDriver's doo r ope n
GRN/RE DPassenger' s doo r ope n Chec
k fo r continuit y t o ground :
Ther e shoul d b e continuity .
NOTE : Befor e testing , remov e th e
No . 3 4 (1 5 A ) fuse . •
Fault y doo r switc h
• Poo r groun d (G401 , G402 , G403 )
• A n ope n i n th e wir e
BLK/WH T
Ceiling ligh t switc h i n
MIDDL E positio n Connec
t t o ground : Th e ceilin g ligh t
shoul d com e on . •
Blow n No . 3 4 (1 5 A ) fus e
• Fault y ceilin g ligh t
• A n ope n in th e WHT/BL U o r
BLK/WHTwir e
RED/YEL
RED/YEL1
Retractabl e headligh t
sub-harnes s (lef t o r
right ) disconnecte d*1 Connec
t batter y powe r t o th e
BLU/RE D termina l (righ t retractor ) o r
BL U termina l (lef t retractor) ; afte r
abou t fou r second s ther e shoul d b e
batter y voltage . •
Fault y retractabl e headligh t contro l
unit
• Seized , damaged , o r improperl y
installe d retracto r linkag e
Roo f unlatche d o r of f Check fo r continuit y t o ground :
Ther e shoul d b e continuity .
*2RED/YEL2
• Fault y roo f holde r switc h
• Fault y roo f loc k switche s
• Poo r groun d (G401 , G402 , G403 )
• A n ope n in th e RED/YEL
2 o r
BLU/GR N wir e
• A n ope n in bot h th e RED/GR N an d
RED/YEL3 wire s
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Brake Ligh t Failur e Senso r Tes t
1. Firs t mak e sur e th e brak e light s com e o n whe n th e
brak e peda l i s pressed .
I f al l th e brak e light s com e on , g o t o ste p 2 .
I f on e o f th e brak e light s doe s no t com e on , chec k
whethe r th e bul b i s blown . I f th e bul b i s OK , g o
t o ste p 2 .
I f non e o f th e brak e light s com e on , chec k th e
brak e ligh t circui t.
2 . Ope n th e trun k lid , an d remov e th e tri m pane l tha t
cover s th e righ t taillight . Watc h th e
ligh t i n th e safet y indicato r whe n th e A (WHT/GRN )
wir e o f th e 6 P connecto r i s grounde d an d th e igni -
tio n switc h is turne d fro m OF F to O N (II) .
RIGH T FAILUR E SENSO R
6 P CONNECTO R
Vie w fro m wir e sid e LEF
T FAILUR E SENSO R
6 P CONNECTO R
View fro m wir e sid e
If th e ligh t come s o n an d stay s
on, ther e is a n ope n in th e A (GRN ) wir e betwee n
th e lef t failur e senso r an d th e righ t failur e sensor .
If th e ligh t doe s no t sta y on , g o
t o ste p 5 .
5. Watc h th e ligh t a s yo u tur n th e igni -
tio n switc h fro m OF F to O N (II ) wit h th e B (BLK ) wir e
o f th e 6 P connecto r grounde d an d th e brak e peda l
pressed .
If th e ligh t come s o n an d stay s
on , replac e th e lef t failur e sensor .
If th e ligh t doe s no t sta y on , chec k
fo r a n ope n in th e B (BLK ) wir e betwee n th e lef t
failur e senso r an d ground , an d chec k fo r a poo r
groun d a t G551 .
If th e ligh t come s o n an d stay s
on , chec k fo r a n ope n in th e A (WHT/GRN ) wir e
betwee n th e safet y indicato r an d th e righ t failur e
sensor .
If th e ligh t doe s no t sta y on , g o
to ste p 3 .
3. Watc h th e ligh t a s yo u tur n th e igni -
tio n switc h fro m OF F t o O N (II ) wit h th e B (GRN )
wir e o f th e 6 P connecto r grounde d an d th e brak e
peda l pressed .
If th e ligh t come s o n an d stay s
on , replac e th e righ t failur e sensor .
If th e ligh t doe s no t sta y on , g o t o
ste p 4 . 4
. Remov e th e rea r tri m pane l tha t cover s th e lef t tail -
light . Watc h th e ligh t a s yo u tur n th e
ignitio n switc h fro m OF F to O N (II ) wit h th e A (GRN )
wir e o f th e 6 P connecto r grounde d an d th e brak e
pedal pressed .
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