1995 ACURA TL Service Repair Manual

Idle Contro l Syste m
Alternato r (ALT ) F R Signa l
This signal s th e PC M whe n th e Alternato r (ALT ) i s charging .
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 GR N 4 P
connecto 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 o
loa d (transmissio n in o r
position ) 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 PC M
connecto r terminal s D 5 an d A26 .
Doe s th e voltag e decreas e whe n
headlight s an d rea r defogge r ar e
turne d on ?
Chec k fo r a n ope n in th e wir e (AL T
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 PC M connec -
tor D (22P) .4. Disconnec t th e GR N 4 P con -
necto r fro m th e ALT .
5 . Connec t th e AL T 4 P connecto r
termina l No . 2 to bod y groun d
with a jumpe r wire .6. Chec k fo r continuit y betwee n
bod y groun d an d PC M con -
necto r termina l D5 .
I s ther e continuity ?
Se e th e AL T inspectio n (se e
sectio n 23 ).
PC M CONNECTOR S
A (26P)D (22P )
LG1 (BRN/BLK )
Wire sid e o f femal e terminal s
Chec k fo r a shor t i n th e wir e (AL T
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 PC M connecto r
D (22P) .4. Chec k fo r continuit y betwee n
bod y groun d an d PC M con -
necto r termina l D5 .
D (22P )
Is ther e continuity ? Repai
r shor t i n th e wir e betwee nthe PC M (D5 ) and th e ALT .
Substitut e a known-goo d PC M
an d recheck . I f prescribe d voltag e
i s no w available , replac e th e origi -
nal PCM .
ALT F R signa l i s OK .
ALT GR N 4P CONNECTO R (C129 )
JUMPE R WIR E
Wir e sid e o f femal e terminal s
Repai r ope n wir e betwee n th e
PC M (D5 ) and th e ALT .
Wire sid e o f femal e terminal s
PC
M CONNECTO R D (22P )
Chec
k fo r a shor t i n th e wir e (AL T
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 PC M
connecto r terminal s D 5 an d A26 .
Inspectio
n o f AL T F R Signal .
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Starter Switch Signal

This signals the PCM when the engine is cranking.

PCM CONNECTORS

A
(26P)
C
(12P)

Wire side of female terminals

Is there battery voltage?

Is the fuse OK?
Repair short in the wire be-

tween the PCM (C6) and the

No. 9 STARTER SIGNAL (7.5

A) fuse or the PGM-FI main

relay.

Replace the No. 9 STARTER

SIGNAL (7.5 A) fuse.

Repair open in the wire between

the PCM
(C6)
and the No. 9

STARTER SIGNAL (7.5 A) fuse.
Starter switch signal is OK.
Inspect the No. 9 STARTER SIG-

NAL (7.5 A) fuse in the under-dash

fuse/relay box.
Check for an open or short in the

wire (STS line):

Measure voltage between PCM

connector terminals C6 and A26

with the ignition switch in the

start position (III).
Inspection of Starter Switch Sig-

nal.
NOTE: Transmission in or position.ProCarManuals.com

Idle Contro l Syste m
Automati c Transaxl e (A/T ) Gea r Position/Signa l
This signal s th e PC M whe n th e transmissio n is in o r position .
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 23 ).
PC M CONNECTOR S
Chec k fo r a shor t i n th e wir e (AT P
P N line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e 16 P connecto r
fro m th e gaug e assembly .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n PC M
connecto r terminal s E2 4 an d
A26 .
A (26P ) E (26P )
Wire sid e o f femal e terminal s
I s ther e approx . 5 V ?
Is ther e continuity ? Repai
r shor t i n th e wir e betwee n
th e PC M (E24 ) an d th e gaug e
assembly .
(To pag e 11-109 )
Inspectio
n o f A/ T Gea r Positio n
Signal .
Chec k 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 .
Check fo r a shor t i n th e wir e (AT P
P N line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e PC M connec -
tor E (26P) .3. Chec k fo r continuit y betwee n
bod y groun d an d PC M con -
necto r termina l E24 .
Substitut e a known-goo d PC M
an d recheck . I f prescribe d volt -
ag e is no w available , replac e th e
origina l PCM .
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(From pag e 11-108 )
Chec k fo r a n ope n in th e wir e (AT P
P N line) :
1. Tur n th e ignitio n switc h OFF .2. Reconnec t th e 16 P connecto r
t o th e gaug e assembly .
3 . Star t th e engine .
4 . Measur e voltag e betwee n PC M
connecto r terminal s E2 4 an d
A26 wit h th e transmissio n inposition .
PCM CONNECTOR S
A (26P)E (26P)
Wire sid e o f femal e terminal s
I s ther e les s tha n 1. 0 V ? Repai
r ope n in th e wir e betwee n
the PC M (E24 ) an d the gaug e
assembly .
Check fo r a n ope n in th e wir e (AT PPN line) :Measur e voltag e betwee n PC M
connecto r terminal s E2 4 an d A2 6
with th e transmissio n i n posi -tion.
Is ther e les s tha n 1. 0 V ? Repai
r ope n in th e gaug e assem -bly.
A/T gea r positio n signa l i s OK .
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Idle Contro l Syste m
Power Steerin g Pressur e (PSP ) Switc h Signa l
This signal s th e PC M whe n th e powe r steerin g loa d is high .
Inspectio n o f PS P switc h signal .
Chec k fo r a n ope n in th e wir e (PS P
S W line) :
1. Tur n th e ignitio n switc h O N (II) .2. Measur e voltag e betwee n PC M
connecto r terminal s B 3 an d A26 .
I s ther e les s tha n 1. 0 V ?
Chec k th e operatio n o f th e PS P
switch :
1 . Star t th e engin e
2. Tur n steerin g whee l t o ful llock .3. Measur e voltag e betwee n PC Mconnecto r terminal s B 3 an d A26 .
I s ther e batter y voltage ?
PCM CONNECTOR S
A (26P)B (16P)
Check fo r a n ope n in th e wir e (PS P
S W line) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e PS P switc h 2 P
connector .
3 . Tur n th e ignitio n switc h O N (II) .
4 . A t th e harnes s side , connec t
th e PS P switc h 2 P connecto r
terminal s No . 1 an d No . 2
wit h a jumpe r wire .5. Measur e voltag e betwee n PC M
connecto r terminal s B 3 an d A26 . Wir
e sid e o f femal e terminal s
I s ther e les s tha n 1. 0 V ? —
Repai r ope n i n th e wire be-
twee n th e PC M (B3 ) an d th e
PS P switch .
— Repai r ope n i n wir e betwee n
the PC M (D22 ) and th e PS Pswitch .
(T o pag e 11-111 )
PS P switc h signa l i s OK . Replac
e th e PS P switch . Wir
e sid e o f femal e terminal s
JUMPERWIRE
PSP SWITC H CONNECTO R (C110 )
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(From pag e 11-110 )
Chec k fo r a shor t i n th e PS P
switch :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e 2 P connecto r
fro m th e PS P switch .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n PC M
connecto r terminal s B 3 an d A26 . PC
M CONNECTOR S
Wir e sid e o f femal e terminal s
I s ther e batter y voltage ?
Is ther e continuity ? Repai
r shor t i n th e wir e betwee n
th e PC M (B3 ) an d th e PS P switch .
Substitut e a known-goo d PC M
an d recheck . I f prescribe d volt -
ag e is no w available , replac e th e
origina l PCM .
Replac
e th e PS P switch .
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Idle Contro l Syste m
Brake Switc h Signa l
This signal s th e PC M whe n th e brak e peda l i s depressed .
Inspection o f Brak e Switc h Signal .
Ar e th e brak e light s o n withou t
depressin g th e brak e pedal ? Inspec
t th e brak e switc h (se e
sectio n 19 ).
Depres s th e brak e pedal .
D o th e brak e light s com e on ?
Is th e fus e OK ?
Chec k fo r a n ope n i n th e wir e
(BKS W line) :
1 . Depres s th e brak e pedal .
2 . Measur e voltag e betwee n PC M
connecto r terminal s E 2 an d
A2 6 wit h th e brak e peda l de -
pressed .
Repair shor t i n th e wire be-
twee n th e brak e switc h an d
th e STO P HOR N (2 0 A ) fuse .
Replac e th e STO P HOR N (2 0 A )
fuse .
Repai r ope n i n th e wir e be -
twee n th e brak e switc h an d
th e STO P HOR N (2 0 A ) fuse .
Inspec t th e brak e switc h (se e
sectio n 19 ).
A (26P )PCM CONNECTOR SE (26P)
Wire sid e o f femal e terminal s
I s ther e batter y voltage ? Repai
r ope n in th e wir e betwee n
th e PC M (E2 ) an d th e brak e switch .
Brak e switc h signa l i s OK . Inspec
t th e STO P HOR N (2 0 A )
fus e i n th e under-hoo d fuse / rela y
box.
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Fast Idl e Therm o Valv e
Descriptio n
T o preven t errati c runnin g whe n th e engin e i s warmin g
up , i t i s necessar y t o rais e th e idl e speed . Th e fas t idl e
therm o valv e i s controlle d b y a thermowa x plunger .
Whe n th e engin e i s cold , th e engin e coolan t surround -
in g th e thermowa x contract s th e plunger , allowin g addi -
tiona l ai r t o b e bypasse d int o th e intak e manifol d s o tha t
th e engin e idle s faster . Whe n th e engin e reache s operat -
in g temperature , th e valv e closes , reducin g th e amoun t
o f ai r bypassin g int o th e intak e manifold .
FASTIDLETHERM OVALVE
IDLEADJUSTIN GSCREW
IACVALV E
AIR BYPAS SVALVE
WAX
Inspectio n
NOTE: Th e fas t idl e therm o valv e i s factor y adjusted ; i t
shoul d no t b e disassembled .
1 . Remov e th e cove r o f th e fas t idl e therm o valve .
2 . Star t th e engine .
3.Pu t you r finge r o n th e valv e sea t are a an d mak e sur e
tha t ther e i s ai r flo w wit h th e engin e col d (engin e
coolan t temperatur e belo w 86°F , 30°C ) an d idling .
FASTIDLETHERM OVALVE
• I f not , replac e th e fas t idl e therm o valv e an d retest .
O-RING SReplace .
12 N- m(1.2 kgf-m , 8. 7 Ibf-ft )
4.
5.
Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h n o
loa d (transmissio n in o r position ) unti l th e radia -
to r fa n come s on , the n le t i t idle .
Chec k tha t th e valv e i s completel y closed . I f not , ai r
suctio n ca n b e fel t i n th e valv e sea t area .
I f an y suctio n is felt , th e valv e is leaking .
Chec k engin e coolan t leve l an d fo r ai r i n th e engin e
coolin g syste m (se e sectio n 10 ).
I f OK , replac e th e fas t idl e therm o valv e an d
recheck .
NOTE: I f th e cove r o f fast idle therm o valv e wa s removed ,
d o th e PC M rese t procedure .
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