1995 ACURA TL engine

PGM-FI System

Engine Control Module (ECM)

Is the low oil pressure light on?

Try to start the engine.

Does the engine start?

Check for an open in the wire or

bulb (MIL line):

1. Turn the ignition switch OFF.

2. Connect the ECM connector ter-

minal A7 to body ground with a

jumper wire.

3. Turn the ignition switch ON (II).
NOTE: If this symptom is intermittent, check for a loose fuse No. 1 (BACK UP

LIGHTS, METER LIGHTS, 10 A) in the under-dash fuse/relay box, a poor con-

nection at ECM terminal A7, or an intermittent open in the GRN/RED wire

between the ECM (A7) and the gauge assembly.

Is the MIL on?

Substitute a known-good ECM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
ECM.
— Repair short in the wire

between NO. 1 (BACK-UP

LIGHTS, METER LIGHTS) (10

A) fuse and gauge assembly.

— Replace No. 1 (BACK-UP

LIGHTS, METER LIGHTS) (10 A)

fuse.

Check for an open in the wires

(PG1, PG2 lines):

1. Turn the ignition switch ON (II).

2. Measure voltage between

body ground and ECM con-

nector terminals A12 and A25

individually.

Is there less than 1.0 V?

Repair open in the wires

between ECM (A7) and gauge

assembly.

Replace the MIL bulb.
ECM CONNECTOR A (26P)

Wire side of female terminals

Repair open in the wire(s)

between ECM and G101 (located

at left side of engine) that had

more than 1.0 V.

ECM CONNECTOR A (26P)

Wire side of female terminals
The Malfunction Indicator Lamp

(MIL) never comes on (even for

two seconds) after ignition is

turned on.

Turn the ignition switch ON (II).

JUMPER WIREProCarManuals.com

The Malfunctio n Indicato r Lam p
(MIL ) stay s o n o r come s o n afte r
tw o seconds .
Chec k th e Diagnosti c Troubl e
Code (DTC) :1. Connec t a sca n too l o r Hond a
PG M Tester .
2 . Tur n th e ignitio n switc h O N (II) .
3 . Rea d th e DT C wit h th e sca n
too l o r Hond a PG M Tester .
NOTE:• Whe n ther e i s n o Diagnosti c Troubl e Cod e (DTC ) stored , th e MI L wil l sta y o n i f th e SC S
servic e connecto r i s connecte d an d th e ignitio n switc h is on .
• I f thi s sympto m is intermittent , chec k for :
— A loos e EC U (ECM ) (1 5 A ) fus e in th e under-hoo d fuse/rela y bo x
— A loos e No . 2 FUE L PUM P (1 5 A ) fus e in th e under-das h fuse/rela y bo x
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D13 ) an d th e servic e chec k con -
necto r
— A n intermitten t ope n i n th e wir e betwee n th e EC M (D22 ) an d th e servic e chec k con -
necto r
— A n intermitten t shor t i n th e wire betwee n th e EC M (A7 ) an d th e gaug e assembl y
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D10) , th e T P senso r an d th e fue l tan k
pressur e senso r ('9 7 - 9 8 models )
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D21 ) an d th e EG R valv e lif t senso r
• Se e th e OB D II sca n too l o r Hond a PG M Teste r user' s manual s fo r specifi c operatin g
instructions .
Ar e an y DTC(s ) indicated ? G
o t o Diagnosti c Troubl e Cod e
(DTC ) char t (se e pag e 11-44 ).
Tr y t o star t th e engine .
Doe s th e engin e start ?
Chec k fo r a shor t i n th e wir e (SC S
line) :
1. Sto p th e engin e an d tur n th eignitio n switc h O N (II) .2. Measur e voltag e betwee n EC M
connecto r terminal s D1 3 an d
D22 .
(To pag e 11-54 ) EC
M CONNECTO R D (22P )
Wir e sid e o f femal e terminal s
I s ther e batter y voltage ? Repai
r shor t t o bod y groun d in
th e wir e betwee n EC M (D13 ) an d
servic e chec k connector .
(To pag e 11-54 )
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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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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
ECMProCarManuals.com

(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 .
ProCarManuals.com

(From pag e 11-112 )
ECM CONNECTOR S
A (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 i n th e wir e be -
twee n th e EC M (B4 ) an d th e
gaug e assembly .Repair ope n in RE D wir e be -
twee n th e gaug e assembl y
an d th e A/ T gea r positio n
switch.
Check fo r a n ope n in th e wir e (AT PPN 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. 0 V ? Repai
r ope n in BLK/BL U wir e be -
twee 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 .
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 . 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 .
B (16P)
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Idle Contro l Syste m
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 .
When 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 .
FASTIDLE THERM O VALV E
IDLEADJUSTIN GSCREW
IAC VALV 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 .
FAST IDL E THERM O VALV E
If 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 fas t idl e therm o valv e wa s removed ,
d o th e EC M rese t procedure .
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