1995 ACURA TL Service Repair Manual

PGM-FI Syste m
Engine Contro l Modul e (ECM ) (cont'd )
(From pag e 11-53 )
Chec k fo r a shor t i n th e wir e (MI L
line) :1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connec -
to r A (26P) .
3. Tur n th e ignitio n switc h O N (II) .
Is th e MI L ON ?Repai r shor t t o bod y groun d i n
th e wir e betwee n th e EC M (A7 )
and MIL .
Substitut e a known-goo d EC M
an d recheck . I f symptom/indica -
tio n goe s away , replac e th e origi -
nal ECM .
(From pag e 11-53 )
I s th e fus e OK ? Repai
r shor t i n th e wir e
betwee n EC U (ECM ) (1 5 A )
fus e an d PGM-F I mai n relay .
Replac e EC U (ECM ) (1 5 A ) fuse .
Inspec t No . 2 FUE L PUM P (1 5 A )
fus e i n th e under-das h fuse/rela y
box.
Is th e fus e OK ? Repai
r shor t i n th e wir e
betwee n No . 2 FUE L PUM P
(1 5 A ) fus e an d PGM-F I mai nrelay .Replac e No . 2 FUE L PUM P(15A) fuse.
Chec k fo r a shor t i n a sensor :
1. Tur n th e ignitio n switc h ON .2. Disconnec t th e 3 P connecto r
o f eac h senso r on e a t time :
• T P senso r
• EG R valv e lif t senso r
• Fue l tan k pressur e senso r
('97-98 models )
(To pag e 11-55 )
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(From pag e 11-54 )
Doe s th e MI L g o of f momentarily ?
I s ther e batter y voltage ?
Chec k fo r a n ope n i n th e wire s
(LG1 , LG 2 lines) :
1 . Reconnec t al l senso r connec -
tors .
2 . Reconnec t th e EC M connecto r
D (22P) .3. Tur n th e ignitio n switc h O N (II) .4. Measur e voltag e betwee n bod y
groun d an d EC M connecto r
terminal s A2 6 an d B 9 individu -
ally .
I s ther e les s tha n 1. 0 V ?
Substitut e a known-goo d EC M
an d recheck . I f symptom/indica -
tio n goe s away , replac e th e origi -
nal ECM .
Replac e th e senso r tha t cause dthe ligh t t o g o out .
ECM CONNECTO R D (22P )
Repai r shor t t o bod y groun d
in th e wir e betwee n EC M(D10) , T P senso r an d fue l tan k
pressur e senso r ('9 7 model) .
Repai r shor t t o bod y groun d in
th e wir e betwee n EC M (D21 )
an d EG R valv e lif t sensor .
A (26P)
Repai r ope n i n th e wire(s )
betwee n EC M (A13 , B1 ) an d
PGM-F I mai n relay .
Chec k fo r poo r connection s
o r loos e wire s a t th e PGM-F I
mai n relay . Wir
e sid e o f femal e terminal s
EC M CONNECTOR S
A (26P)B (16P)
Repai r ope n i n th e wire(s )
betwee n EC M (A26 , B9 ) an d
G10 1 tha t ha d mor e tha n 1. 0 V . EC
M CONNECTOR S
B (16P)
Wire sid e o f femal e terminal s
Chec k fo r a n ope n i n th e wire s
(IGP1 , IGP 2 lines) :
1 . Disconnec t th e junctio n con -
nector , MA F senso r an d IA C
valv e connectors .
2. Tur n th e ignitio n switc h O N (II) .3. Measur e voltag e betwee n bod ygroun d an d EC M connecto rterminals A1 3 an d B 1 individu -
ally .I
s ther e continuity ?
Chec
k fo r a shor t i n th e wire s
(VCC1 , VCC 2 lines) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connec -tor D (22P) .3. Chec k fo r continuit y betwee nbody groun d an d EC M con -necto r terminal s D1 0 an d D2 1individually .
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Idle Control System

System Description

The idle speed of the engine is controlled by the Idle Air Control (IAC) Valve.

The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled by the

ECM. When the IAC Valve is activated, the valve opens to maintain the proper idle speed.

From

PGM-FI

MAIN

RELAY

INTAKE

MANIFOLD
VARIOUS SENSORS

FAST

IDLE

THERMO

VALVE
IDLE

ADJUSTING

SCREW
ENGINE

COOLANT
ENGINE

COOLANT

IAC VALVE
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Idle Contro l Syste m
1. Afte r th e engin e starts , th e IA C valv e open s fo r a certai n time . Th e amoun t o f ai r i s increase d t o rais e th e idl e spee d
abou t 150-30 0 rpm .
2 . Whe n th e coolan t temperatur e i s low , th e IA C valv e i s opene d t o obtai n th e prope r fas t idl e speed . Th e amoun t o f
bypasse d ai r i s thu s controlle d in relation to th e engin e coolan t temperature .
IDLE SPEE D(rpm)
ENGIN ECOOLAN T TEMPERATUR E
3. Whe n th e idl e spee d is ou t o f specificatio n an d th e sca n too l doe s no t indicat e Diagnosti c Troubl e Cod e (DTC ) P050 5
o r P1508 , chec k th e followin g items :
• Adjus t th e idl e spee d (se e pag e 11-117 )
• Starte r switc h signa l (se e pag e 11-107 )
• Ai r conditionin g signa l (se e pag e 11-108 )
• AL T F R signa l (se e pag e 11-110 )
• Brak e switc h signa l (se e pag e 11-111 )
• A/ T gea r positio n signa l (se e pag e 11-112 )
• PS P switc h signa l (se e pag e 11-114 )
• Fas t idl e therm o valv e (se e pag e 11-116 )
• Hose s an d connection s
• IA C valv e an d it s mountin g O-ring s
4 . I f th e abov e item s ar e normal , substitut e a known-goo d IA C valv e an d readjus t th e idl e spee d (se e pag e 11-117 ).
I f th e idl e spee d stil l canno t b e adjuste d t o specificatio n (an d th e sca n too l doe s no t indicat e DT C P050 5 o r P1508 )
afte r IA C valv e replacement , substitut e a known-goo d EC M an d recheck . I f sympto m goe s away , replac e th e origina l
ECM.
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Starter Switc h Signa l
This signal s th e EC M whe n th e engin e is cranking .
NOTE: Transmissio n in o r position .
A (26P)ECM CONNECTOR S
Wir e sid e o t femal e terminal s
I s ther e batter y voltage ?
Is th e fus e OK ? Repai
r shor t i n th e wir e be -
twee n th e EC M (B5 ) an d th eNo . 9 STARTE R SIGNA L (7. 5
A ) fus e o r th e PGM-F I mai n
relay .Replac e th e No . 9 STARTE R
SIGNA L (7. 5 A ) fuse .
B (16P )
Inspectio n o f Starte r Switc h Sig -nal.
Chec k fo r a n ope n o r shor t i n th e
wir e (ST S line) :
Measur e voltag e betwee n EC M
connecto r terminal s B 5 an d A2 6on th e EC M connector s wit h th e
ignitio n switc h i n th e star t posi -
tion (III) .
Starte r switc h signa l i s OK . Inspec
t th e No . 9 STARTE R SIG -
NA L (7. 5 A ) fus e in th e under-das h
fuse/rela y box .
Repai r ope n in th e wir e betwee n
the EC M (B5 ) and th e No . 9STARTE R SIGNA L (7. 5 A ) fuse .
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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.ECM CONNECTOR S
A (26P)
Chec k 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 A/ C pressur e
switc h connector .
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 B 3
an d A26 .
Wire sid e o f femal e terminal s
I s ther e batter y voltage ?
Chec k fo r a n ope n i n th e wir e
(ACC line) :1. Tur n th e ignitio n switc h OFF .
2 . Reconnec t th e A/ C pressur e
switc h connector.
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 an d
A2 6 wit h a jumpe r wire sever -
a l times .
(T o pag e 11-109 ) Chec
k 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 -
tor B (16P) .3. Chec k fo r continuit y betwee n
bod y groun d an d EC M con -
necto r termina l B3 . EC
M CONNECTO R B (16P )
Wir e sid e o f femal e terminal s
I s ther e continuity ? Repai
r shor t i n th e wir e betwee n
the EC M (B3 ) an d th e A/ C pres -sure switch .
Substitut e a known-goo d EC M
an d recheck . I f prescribe d volt -
ag e is 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 ).
ECM CONNECTO R A (26P )
Wir e sid e o f femal e
terminal s JUMPE
R
WIRE
B (16P )
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(From pag e 11-108 )
I s ther e a clickin g nois e fro m
th e A/ C compresso r clutch ?
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 i n th e wire
(AC C line) :Momentaril y connec t th e A/ C
clutc h rela y connecto r termina l
No. 2 to bod y groun d wit h ajumpe r wir e severa l times . A/
C CLUTC H RELA Y CONNECTO R (C328 )JUMPE RWIRE
Wire sid e o f
femal e terminal s
I s 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 i n th e wir e betwee n
th e EC M (A8 ) an d th e A/ C clutc h
relay.
ECM CONNECTOR S
A (26P)B (16P)
Chec k fo r a n ope n i n th e wir e
(AC C line) :
Measur e voltag e betwee n EC M
connecto r terminal s A2 6 an d B3 . Wir
e sid e o f femal e terminal s
I s 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 (B3 ) an d th e A/ C switch .
Substitut e a known-goo d EC M
an d recheck . I f symptom/indi -
catio n goe s away , replac e th e
origina l ECM .
Se e th e ai r conditione r inspec -
tion (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 .
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 EC 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 EC 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 . 4 to bod y groun d
with a jumpe r wire .6. Chec k fo r continuit y betwee nbody groun d an d EC 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 ). EC
M CONNECTOR S
A (26P)D (22P)
Wire sid e o f femal e terminal s
D (22P)
Repai r shor t i n th e wir e betwee nthe EC M (D5 ) and th e ALT .
ALT F R signa l i s OK .
ALT GR N 4P CONNECTO R (C127 )
JUMPE R WIR E
Wir e sid e o f femal e terminal s
Repai r ope n wir e betwee n th e
ECM (D5 ) and th e ALT .
ECM CONNECTO R D (22P )
Wir e sid e o f femal e terminal s
Substitut
e a known-goo d EC M
an d recheck . I f prescribe d voltag e
i s no w available , replac e th e origi -
nal ECM .
Is ther e continuity ?
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 EC M connecto r
D (22P) .4. Chec k fo r continuit y betwee n
bod y groun d an d EC M con -
necto r termina l D5 .
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 EC M
connecto r terminal s D 5 an d A26 .
Inspectio
n o f AL T F R Signal .
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