1995 ACURA TL light

Powertrain Control Module (PCM)

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 PCM terminal A7, or an intermittent open in the GRN/RED wire

between the PCM (A7) and the gauge assembly.

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 PCM connector ter-

minal A7 to body ground with a

jumper wire.

3. Turn the ignition switch ON (II).

Is the MIL on?

Substitute a known-good PCM,

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.
— Repair short or open 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.

PCM CONNECTOR A (26P)

Check for an open in the wires

(PG1, PG2 lines):

1. Turn the ignition switch ON (II).

2. Measure voltage between

body ground and PCM con-

nector terminals A12 and A25

individually.
Wire side of female terminals

Is there less than 1.0 V?
Repair open in the wire(s)

between PCM and G101 (located

at intake manifold) that had

more than 1.0 V.

PCM CONNECTOR A (26P)

JUMPER WIRE

Wire side of female terminals
Repair open in the wires

between PCM (A7) and gauge

assembly.

Replace the MIL bulb.
Substitute a known-good PCM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.
Turn the ignition switch ON (II).
The Malfunction Indicator Lamp

(MIL) never comes on (even for

two seconds) after ignition is

turned on (II).ProCarManuals.com

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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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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Idle Contro l Syste m
Idle Spee d Settin g
Inspection/Adjustmen t
NOTE:
Before settin g th e idl e speed , chec k th e followin g
items :
— Th e MI L ha s no t bee n reporte d on .
— Ignitio n timin g
— Spar k plug s
— Ai r cleane r (ACL )
— PC V syste m
(Canada ) Pul l th e parkin g brak e leve r up . Star t th e
engine , the n chec k tha t th e headlight s ar e off .
1 . Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
no loa d (transmissio n i n o r position ) unti l th e
radiato r fa n come s on , the n le t i t idle .
2 . Connec t a OBDI I sca n too l (se e pag e 11-32 ) o r
tachometer .
• Connec t a tachomete r t o th e ignitio n contro l
module (ICM ) secondary , or.. .
TACHOMETE R
ICM
Remov e th e rubbe r ca p fro m th e tachomete r
connecto r an d connec t a tachometer .
TACHOMETE R TACHOMETE R
CONNECTOR
RUBBERCAP
3. Disconnec t th e IA C valv e connector .
4.
5 .
IA C VALV E
Start th e engin e wit h th e accelerato r peda l slightl y
depressed . Stabiliz e th e rp m a t 1,000 , the n slowl y
releas e th e peda l unti l th e engin e idles .
Check idlin g in no-loa d conditions : headlights , blow -
er fan , rea r defogger , radiato r fan , an d ai r conditione r
ar e no t operating .
Idl e spee d shoul d be :
480 5 0 rp m
(in o r position )
Adjus t th e idl e speed , i f necessary , b y turnin g th e
idl e adjustin g screw .
NOTE : Afte r adjustin g th e idl e spee d i n thi s step ,
rechec k th e ignitio n timin g (se e sectio n 23 ).
I f i t i s ou t o f spec , g o bac k t o ste p 4 .
IDL E ADJUSTIN G SCRE W
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6. Tur n th e ignitio n switc h OFF .
7 . Reconnec t th e 2 P connecto r o n th e IA C valve , the n
d o th e PC M rese t procedure .
8 . Restar t an d idl e th e engin e wit h no-loa d condition s
fo r on e minute , the n chec k th e idl e speed .
NOTE : (Canada ) Pul l th e parkin g brak e leve r up .
Star t th e engine , the n chec k tha t th e headlight s ar e
off.
Idle spee d shoul d be :
640 5 0 rp m
(in o r position )
9 . Idl e th e engin e fo r on e minut e wit h headlight s (Low )
O N an d chec k th e idl e speed .
Idl e spee d shoul d be :
650 5 0 rp m
(in o r position )
10 . Tur n th e headlight s off .
Idle th e engin e fo r on e minut e wit h heate r fa n switc h
at H I an d ai r conditione r on , the n chec k th e idl e speed .
Idl e spee d shoul d be :
650 5 0 rp m
(in o r position )
NOTE : I f th e idl e spee d i s no t withi n specification ,
se e Sympto m Char t o n pag e 11-36 .
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Intake Ai r Syste m
Throttl e Bod y
Descriptio n
The throttl e bod y i s a single-barre l side-draf t type . Th e
lowe r portio n o f th e throttl e valv e i s heate d b y engin e
coolan t fro m th e cylinde r head . Th e idl e adjustin g screw ,
whic h increases/decrease s bypas s air , an d th e Evapora -
tiv e Emissio n (EVAP ) Contro l Caniste r por t ar e locate d o n
the to p o f th e throttl e body .
THROTTL EPOSITION(TP)SENSO R
IDLE ADJUSTIN GSCREW
THROTTL E
VALV E
THROTTLE
STOPSCRE W
(non-adjustable )
Inspection
CAUTION : D o no t adjus t th e throttl e sto p screw . I t i s
prese t a t th e factory .
1 . Disconnec t th e vacuu m hos e (t o th e EVA P contro l
canister ) fro m th e to p o f th e throttl e body ; connec t
a vacuu m gaug e t o th e throttl e body .
2 . Star t th e engine . Hol d th e engine at 3,00 0 rp m wit h
no loa d (transmissio n i n ! o r position ) unti l th e
radiato r fa n come s on , the n le t i t idle .
VACUU M PUMP/GAUG EA973X - 04 1 - XXXX X
3. Allo w th e engin e t o idle , an d chec k tha t th e gaug e
indicate s n o vacuum .
If ther e i s vacuum , chec k th e throttl e cabl e (se e
pag e 11-135 ).
4 . Chec k tha t vacuu m is indicate d o n th e gaug e whe n
the throttl e is opene d slightl y fro m idle .
If th e gaug e indicate s n o vacuum , chec k th e throt -
tl e bod y port . I f th e throttl e bod y por t i s clogged ,
clea n i t wit h carbureto r cleaner .
5 . Sto p th e engine , an d chec k tha t th e throttl e cabl e
operates smoothly without bindin g o r sticking .
I f ther e ar e an y abnormalitie s i n th e abov e steps ,
check for .
— Excessiv e wea r o r pla y i n th e throttl e valv e shaft .
— Stick y o r bindin g throttl e leve r a t ful l close posi-
tion.
— Clearanc e betwee n throttl e sto p scre w an d throt -
tl e leve r a t ful l clos e position .
There shoul d b eno clearance .THROTTLE LEVE R
THROTTL ELEVER
THROTTL E STO P SCRE W(Non-adjustable )
Replace th e throttl e bod y i f ther e is excessiv e pla y i n th e
throttl e valv e shaf t o r i f th e shaf t i s bindin g o r sticking .
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Emission Control System

Positive Crankcase Ventilation (PCV) System

Description

The Positive Crankcase Ventilation (PCV) system is

designed to prevent blow-by gas from escaping to the

atmosphere. The PCV valve contains a spring-loaded

plunger. When the engine starts, the plunger in the PCV

valve is lifted in proportion to intake manifold vacuum and

the blow-by gas is drawn directly into the intake manifold.

INTAKE

MANIFOLD
BREATHER PIPE

PCV HOSE

PCV VALVE

BLOW-BY VAPOR

FRESH AIR
Inspection

1. Check the PCV hoses and connections for leaks and

clogging.

PCV HOSE

BREATHER

PIPE

PCV VALVE

2.
At idle, make sure there is a clicking sound from the

PCV valve when the hose between the PCV valve

and intake manifold is lightly pinched with your fin-

gers or pliers.

Gently pinch here

If there is no clicking sound, check the PCV valve

grommet for cracks or damage. If the grommet is

OK, replace the PCV valve and recheck.ProCarManuals.com

Partial Lock-up

Lock-up Control Solenoid Valve A: ON Lock-up Control Solenoid Valve B: OFF

The PCM switches the solenoid valve A on to release modulator pressure in the left cavity of the lock-up shift valve.

Modulator pressure in the right cavity of the lock-up shift valve overcomes spring force, and the lock-up shift valve is

moved to the left side.

Line pressure is then separated into the two passages to the torque converter:

Torque Converter Inner Pressure: enters into right side to engage lock-up clutch

Torque Converter Back Pressure: enters into left side to disengage lock-up clutch

Back pressure (F2) is regulated by the lock-up control valve, whereas the position of the lock-up timing valve is determined

by the throttle B pressure, tension of the valve spring, and pressure regulated by the modulator valve. Also the position of

the lock-up control valve is determined the back pressure of the lock-up control valve and torque converter pressure regulat-

ed by the check valve. With the lock-up control solenoid valve B kept off, modulator pressure is maintained in the left side of

the lock-up control valve; the lock-up control valve is moved slightly to the right side. This slight movement of the lock-up

control valve causes back pressure to be lowered slightly, resulting in partial lock-up.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

The hydraulic circuit shows '97 - '98 models; '96 model is similar.ProCarManuals.com