1997 ACURA NSX Service Repair Manual

Idle Contro l Syste m
Air Conditionin g Signa l
This signal s th e EC M whe n ther e is a deman d fo r coolin g fro m th e ai r conditionin g system .
Inspectio n o f Ai r Conditionin gSignal.
Check fo r a shor t i n th e wir e
(AC S line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e 12 P connecto r
fro m th e coolin g fa n contro l
unit.3. Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n EC M
connecto r terminal s C 2 an d
A26 .
Is ther e approx . 1 0 V ?
Chec k fo r a n ope n i n th e wir e
(ACS line) :1. Tur n th e ignitio n switc h OFF .
2 . Reconnec t th e 12 P connecto r t o
th e coolin g fa n contro l unit .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Momentaril y connec t EC M
connecto r terminal s A 8 t o
A2 6 severa l time s wit h ajumpe r wire .
(To pag e 11-119 )
Check fo r a shor t i n th e wir e
(AC S line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e EC M connec -
to r C (12P ) fro m th e ECM .
3 . Chec k fo r continuit y betwee n
EC M connecto r termina l C 2
an d bod y ground .
I s ther e continuity ?
Substitut e a known-goo d
EC M an d rechec k (se e pag e
11-3 9 fo r immobilize r infor -
mation) . I f prescribe d voltag e
i s no w available , replac e th e
origina l ECM .
Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ). Repai
r shor t i n th e wir e
betwee n th e EC M (C2 ) an d th e
coolin g fa n contro l unit .
Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
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(From pag e 11-118 )
Chec k th e A/ C operation :
1 . Star t th e engine .
2. Tur n th e blowe r switc h ON .3. Tur n th e A/ C switc h ON .
Doe s th e A/ C operate ?
Ai r conditionin g signa l i s OK . Chec
k fo r a n ope n in th e wire :
Momentaril y connec t th e No . 4 ter -
mina l o f th e 4 P connecto r o n th e
A/ C clutc h rela y t o bod y groun d
several times .
Is ther e a clickin g nois e fro m th e
A/ C compresso r clutch ? Se
e ai r conditione r inspectio n (se e
sectio n 22 ).
Repai r ope n in th e wir e betwee n
th e EC M (AS ) an d th e A/ C clutc h
relay.
Is voltag e les s tha n 1. 0 V ? Repai
r ope n i n th e wir e betwee n
th e EC M (C2 ) an d th e A/ C switch .
I
s ther e a clickin g nois e fro m th e
A/ C compresso r clutch ?
Substitute a known-goo d EC M
an d rechec k (se e pag e 11-3 9
fo r immobilize r information) . I f
symptom/indicatio n goe s
away , replac e th e origina l
ECM.See th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
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Idle Contro l Syste m
Alternato r (ALT ) F R Signa l
This signal s th e EC M whe n th e Alternato r (ALT ) i s charging .
Inspection o f AL T F R Signal .
Chec k fo r a shor t i n th e wir e
(ALT F line) :
1 . Disconnec t th e GR N 4 P con -
necto r fro m th e ALT .
2 . Tur n th e ignitio n switc h O N (II) .
3 . Measur e voltag e betwee n EC M
connecto r terminal s D 5 an d
A26.
Is ther e approx . 5 V ?
Chec k th e operatio n o f th e ALT :
1. Tur n th e ignitio n switc h OFF .2. Reconnec t th e AL T GRI M 4 Pconnecto r t o th e ALT .
3 . Star t th e engine . Hol d th e
engin e a t 3,00 0 rp m wit h n oloa d (A/ T in o r position ,
M/ T in neutral ) unti l th e radiato r
fa n come s on , the n le t i t idle .
4 . Measur e voltag e betwee n EC M
connecto r terminal s D 5 an d
A26 .
I
Doe s th e voltag e decreas e whe n
headlight s an d rea r defogge r ar e
turne d on ?
(T o pag e 11-121 ) Chec
k fo r a shor t i n th e wir e
(ALT F line) :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e negativ e bat -
ter y cabl e fro m th e battery .
3 . Disconnec t th e EC M connec -
to r D (22P ) fro m th e ECM .
4 . Chec k fo r continuit y betwee n
EC M connecto r termina l D 5
an d bod y ground .
I s ther e continuity ? Repai
r shor t i n th e wir e betwee n
the EC M (D5 ) and th e ALT .
Substitut e a known-goo d EC M
an d rechec k (se e pag e 11-3 9 fo r
immobilize r information) . I f pre -
scribe d voltag e is no w available ,
replac e th e origina l ECM .
AL T F R signa l i s OK .
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(From pag e 11-120 )
Chec k fo r a n ope n i n th e wir e
(ALT F line) :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e negativ e batter y
cabl e fro m th e battery .
3 . Disconnec t th e EC M connec -
to r D (22P ) fro m th e ECM .
4 . Disconnec t th e GR N 4 P con -
necto r fro m th e ALT .
5 . Connec t No . 2 termina l t o bod y
groun d wit h a jumpe r wire .6. Chec k fo r continuit y betwee n
EC M connecto r termina l D 5
an d bod y ground .
I s ther e continuity ? Repai
r ope n in th e wir e betwee n
the EC M (D5 ) and th e ALT .
See th e AL T inspectio n (se esectio n 23 ).
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Idle Contro l Syste m
Automati c Transaxl e (A/T ) Gea r Positio n Signa l
Does th e indicato r ligh t prop -erly?See th e A/ T gea r positio n indica -
to r inspectio n (se e sectio n 14 ).
Chec k fo r a shor t i n th e wir e
(ATF P N line) :1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e SO P (C412 )connecto r fro m th e gaug eassembly .3. Disconnec t th e 26 P connecto r
fro m th e TCM .
4 . Tur n th e ignitio n switc h O N (II) .
5 . Measur e voltag e betwee n
EC M connecto r terminal s B 4
an d A26 .
Is ther e approx . 5V ? Chec
k fo r a shor t i n th e wir e
(AT F O N line) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connecto r
B (16P ) fro m th e ECM .
3 . Chec k fo r continuit y betwee n
EC M connecto r termina l B 4
an d bod y ground .
I s ther e continuity ?
(To pag e 11-123 )
Repair shor t i n th e wir e betwee n
th e EC M (B4 ) an d th e gaug e
assembly .
Substitute a known-goo d EC M
an d rechec k (se e pag e 11-3 9 fo r
immobilize r information) . I f pre -
scribe d voltag e i s no w available ,
replac e th e origina l ECM .
This signal s th e EC M whe n th e transmissio n is in o r position .
Inspection o f A/ T Gea r Positio nSignal.
Check th e operatio n o f th e A/ T
gea r positio n switch :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Observ e th e A/ T shif t positio n
indicato r an d selec t eac h posi -
tion separately .
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(From pag e 11-122 )
Chec k fo r a n ope n i n th e wir e
(AT F P N line) :
1. Tur n th e ignitio n switc h OFF .2. Reconnec t th e 30 P (C412 ) con -necto r t o th e gaug e assembly .
3 . Reconnec t th e 26 P connecto r
to th e TCM .4. Star t th e engine .
5 . Measur e voltag e betwee n EC M
connecto r terminal s B 4 an d
A26 wit h th e transmissio n inposition .
Is ther e les s tha n 1. 0 V ? Repai
r ope n i n th e wir e
betwee n th e EC M (B4 ) an d th egaug e assembly .Repair ope n i n GR N wir e
betwee n th e gaug e assembl y
an d th e A/ T gea r positio n
switch .
Chec k fo r a n ope n i n th e wir e
(AT P P N line) :
Measur e voltag e betwee n EC M
Connecto r terminal s B 4 an d A2 6
with th e transmissio n i n posi -tion.
Is ther e les s tha n 1.0V ? Repai
r ope n i n GRN/WH T wir e
betwee n th e gaug e assembl y an d
th e A/ T gea r positio n switch .
A/ T gea r positio n signa l i s OK .
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Idle Contro l Syste m
Neutra l Switc h Signa l (M/T )
This signal s th e EC M whe n th e transmissio n is in neutral .
Inspectio n o f neutra l switc h signal .
Chec k fo r a n ope n i n th e wir e
(NTS W line) :
1. Tur n th e ignitio n switc h O N (II) .2. Measur e voltag e betwee n EC M
connecto r terminal s B 4 an d
A26 .
Is ther e voltage ?
Chec k fo r a shor t i n th e wir e
(NTS W line) :
1. Shif t transmissio n int o gear .2. Measur e voltag e betwee n EC M
connecto r terminal s B 4 an d
A26 .
Is ther e approx . 5 V ?
Neutra l switc h signa l i s OK . I
s ther e voltage ? Replac
e th e neutra l switc h (se e
sectio n 13 ).
Repai r ope n i n th e wir e
betwee n th e EC M (B4 ) an d
th e neutra l switch .
Repai r ope n i n BL K wir e
betwee n th e neutra l switc h
an d G10 1 (locate d a t righ t mid -
dl e o f engine) .
Chec k fo r a shor t i n th e wir e
(NTS W line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e EC M connec -
to r B (16P ) fro m th e ECM .
3 . Disconnec t th e 3 P connecto r
fro m th e neutra l switch .
4 . Chec k fo r continuit y betwee n
EC M connecto r termina l B 4
Is ther e continuity ?Repair shor t i n th e wir e betwee nthe EC M (B4 ) an d th e neutralswitch .
Replac e neutra l switc h (se e
sectio n 13 ).
Substitut e a known-goo d EC M
an d rechec k (se e pag e 11-3 9
fo r immobilize r information) . I f
prescribe d voltag e i s no w
available , replac e th e origina l
ECM.
Chec k fo r a n ope n i n th e wir e
(NTS W line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e 3 P connecto r
fro m th e neutra l switch .
3 . Connec t neutra l switc h con -
necto r terminal s No . 1 to No . 3 .
4 . Tur n th e ignitio n switc h O N (II) .
5 . Measur e voltag e betwee n EC M
connecto r terminal s B 4 an d
A26 .
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Clutch Switc h Signa l (M/T )
This signal s th e EC M whe n th e clutc h is engaged .
Inspection o f clutc h switc h signal .
Chec k fo r a n ope n i n th e wir e
(MTCL S line) :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Measur e voltag e betwee n EC M
connecto r terminal s C 4 an d
A26 .
Is voltag e les s tha n 1. 0 V ?
Chec k fo r shor t i n th e wir e
(MTCL S line) :
1 . Depres s th e clutc h pedal .
2 . Measur e voltag e betwee n EC M
connecto r terminal s C 4 an d
A26 .
(To pag e 11-126 ) Chec
k th e clutc h switch :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e 3 P connecto r
fro m th e clutc h switch .
3 . Chec k fo r continuit y betwee n
th e clutc h switc h connecto r
terminal s No . 1 an d No . 3 .
I s ther e continuity ? Adjus
t th e clutc h switch .
Replac e th e clutc h switch .
I s ther e approx . 5 V ? Repai
r ope n in th e wir e betwee n
th e EC M (C4 ) an d th e clutc h
switch.
Repair ope n in BL K wir e betwee n
th e clutc h switc h an d G40 1
(locate d behin d lef t kic k panel) .
Chec
k fo r a n ope n i n th e wir e
(MTCL S line) :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Measur e voltag e betwee n th e
clutc h switc h connecto r termi -
na l No . 1 an d bod y ground .
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