1995 ACURA TL lock

Position
Hydrauli c pressur e i s no t applie d t o th e clutches . Powe r i s no t transmitte d t o th e countershaft .
Positio n
Hydrauli c pressur e i s no t applie d t o th e clutches . Powe r i s no t transmitte d t o th e countershaft .
Th e countershaf t i s locke d b y th e parkin g brak e paw l interlockin g th e parkin g gear .
4TH CLUTCH 1ST CLUTCH 2ND CLUTCH
TORQU ECONVERTE R
MAINSHAFT
COUNTERSHAF T
REVERS E
CLUTCH
3RD CLUTCH
2ND GEA RONE-WA Y
CLUTC H
1ST GEA RONE-WA Y CLUTC H
(cont'd)
1ST-HOL DCLUTCH PARKIN
GGEAR
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Electronic Control System

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a linear solenoid and four solenoid

valves. Shifting and lock-up are electronically controlled for comfortable driving under all conditions.

The PCM is located below the dashboard, under the front lower panel on the passenger's side.ProCarManuals.com

Description
Electronic Contro l Syste m (cont'd )
Lock-up Contro l
From senso r inpu t signals , th e PC M determine s whethe r t o tur n th e lock-u p O N o r OFF , an d activate s lock-u p contro l
solenoi d valv e A and/o r B accordingly .
Th e combinatio n o f drivin g signal s t o lock-u p contro l solenoi d valve s A an d B is show n in th e tabl e below .
Shif
t Contro l
Th e PC M
instantaneously determine s whic h gea r shoul d b e selecte d b y variou s signal s sen t fro m sensors , an d i t actuate s
th e shif t contro l solenoi d valve s A an d B to contro l shifting . Also , a Grad e Logi c Contro l Syste m ha s bee n adopte d to contro l
shifting in positio n whil e th e vehicl e is ascendin g o r descendin g a slope , o r reducin g speed .
Shif t contro l solenoi d valv e
Positio n (gear )
(1st)
A
OFF
(2nd )
(3rd)
(4th)
(2nd )
(1st)
(Reverse )
ON
O N
OF F
ON
OF F
ON
B
O N
O N
OF F
OF F
ON
O N
OF F
Dut y operatio n
ONOF FON
O N
AB
OF F
OF F
ON
O N
OF F
ON
ON
Lock-u p contro l solenoi d valv e
Lock-u p conditio n
Lock-u p OF F
Lock-up , sligh t
Lock-up , hal f
Lock-up , ful l
Lock-u p
during deceleratio n
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Description
NOTE:
Shift schedule s betwee n 3r d an d 4t h gea r store d i n th e PC M enabl e th e PCM' s fuzz y logi c t o automaticall y selec t th e
mos t suitabl e gea r accordin g t o th e magnitud e o f a gradient .
Fuzz y logi c i s a for m o f artificia l intelligenc e tha t let s computer s respon d t o changin g condition s muc h lik e a huma n
mind would .
Descendin g Contro l
whe n th e throttl e is close d become s faste r tha n th e se t spee d fo r fla t roa d drivin g t o wide n th e 3r d gea r drivin g area .
This, i n combinatio n wit h engin e brakin g fro m th e deceleratio n lock-up , achieve s smoot h drivin g whe n th e vehicl e is
descending .
Ther e ar e tw o descendin g mode s wit h differen t 3r d gea r drivin g area s accordin g t o th e magnitud e o f a gradien t store d i n
th e PCM .
When th e vehicl e is in 4t h gear , an d yo u ar e deceleratin g o n a gradua l hill , o r whe n yo u ar e applyin g th e brake s o n a stee p
hill, the transmissio n will downshif t to 3r d gear . Whe n you accelerate , the transmissio n will the n retur n to 4t h gear .
Electroni c Contro l Syste m (cont'd )
Ascendin g Contro l
3r d gea r t o preven t th e transmissio n fro m frequentl y shiftin g betwee n 3r d an d 4t h gears , s o th e vehicl e ca n ru n smoot h
an d hav e mor e powe r whe n needed . position
, th e syste m extend s th e engagemen t are a o f
Whe n th e PC M determine s tha t th e vehicl e i s climbin g a hil l i n
ASCENDIN G MOD E DESCENDIN G MOD E
Deceleratio n Contro l
Whe n th e vehicl e goe s aroun d a corner , an d need s to decelerat e firs t an d the n accelerate , th e PC M set s th e dat a fo r deceleratio n
contro l t o reduc e th e numbe r o f time s th e transmissio n shifts . Whe n th e vehicl e i s deceleratin g fro m speed s abov e 3 0 mp h
(4 8 km/h) , th e PC M shift s th e transmissio n fro m 4t h to 2n d earlie r tha n norma l t o cop e wit h upcomin g acceleration .
Whe
n th e PC M determine s tha t th e vehicl e i s goin g dow n a hil l i n position , th e shift-u p spee d fro m 3r d t o 4t h gea r
3RD/4T H SHIFTIN GCHARACTERISTIC SCONTROL ARE A
Flat roa dmod e
. Stee p descendin gmode
Gradua l descendin gmode
Vehicl e spee dmph (km/h )Vehicle spee dmph (km/h )
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Description

The hydraulic control system is controlled by the ATF pump, valves, and accumulators in the valve bodies. The ATF pump

is driven by splines on the end of the torque converter which is attached to the engine.

Fluid from the ATF pump flows through the regulator valve to maintain specified pressure through the main valve body to

the manual valve, directing pressure to each of the clutches.

The valve body includes the main valve body, the secondary valve body, the ATF pump body, the regulator valve body,

the throttle valve body, and the accumulator body. The throttle valve body is joined with the linear solenoid.

The shift control solenoid valves A and B are bolted to the secondary valve body. The lock-up control solenoid valve assem-

bly is bolted to the outside of the torque converter housing.

ATF PUMP BODY

ACCUMULATOR BODY

SHIFT CONTROL

SOLENOID VALVE

A/B

REAR COVER

REGULATOR VALVE

BODY

THROTTLE VALVE BODY

SECONDARY VALVE BODY

MAIN VALVE BODY

ATF PASSAGE

NOTE: The illustration shows '96 model; '97 - '98 models are similar.
Hydraulic ControlProCarManuals.com

Hydraulic Control

ATF Pump Body

The ATF pump body is located on the torque converter housing. The ATF pump body consists of the ATF pump gears, the

relief valve, the lock-up control valve, the lock-up timing valve, and the torque converter check valve. The torque converter

check valve is located between the ATF pump body and the torque converter housing.

Accumulator Body

The accumulator body is located on the torque converter housing next to the ATF pump body. The accumulator body

houses the 3rd accumulator piston and the 4th accumulator piston.

Regulator Valve Body

The regulator valve body is located on the ATF pump body. The regulator valve body consists of the regulator valve, the

cooler relief valve, and the lock-up shift valve.

REGULATOR VALVE

BODY

4TH ACCUMULATOR
REGULATOR VALVE

3RD ACCUMULATOR
ATF PUMP BODY

RELIEF VALVE

TORQUE CONVERTER

CHECK VALVE
LOCK-UP CONTROL

VALVE

LOCK-UP TIMING

VALVE

COOLER RELIEF

VALVE

ACCUMULATOR BODY

NOTE: The illustration shows '96 model; '97 - '98 models are similar.

(cont'd)ProCarManuals.com

Description
Line Pressur e - Modulato r Pressur e
- Throttl e B Pressur e
- Clutc h Pressur e
Distributio n o f Hydrauli c Pressur e
Regulato r Valv e Torque Converte r Pressur e
Lubricatio n Pressur e
T o Regulat e Lin e Pressur e
Manua l Valv e
Modulato r Valv e
To Selec t Lin e Pressur e
Modulato r Pressur e Clutc
h Pressur e
Shif t Contro l Solenoi d Valve s
Lock-u p Contro l Solenoi d Valve s
1-2 Shif t Valv e
2-3 Shif t Valv e
3-4 Shif t Valv e
Throttl e Valv e
Clutc h Pressur e
Throttle B Pressur e
NO.
1
2
3
4
4'
4"
5
5 '
6
6A
6 B
6C
6D
DESCRIPTIO N O F PRESSUR E
LIN E
LIN E
LIN E
LIN E
LIN E
LIN E
LINE
LIN E
LIN E
MODULATO R
MODULATO R
MODULATO R
MODULAT E (DUT Y CONTROL )
NO.
7
10
10 '
11
2 0
2 5
30
4 0
5 0
5 5
56
57
7 0
DESCRIPTIO N O F PRESSUR E
LIN E
1S T CLUTC H
1S T CLUTC H
1S T CLUTC H
2N D CLUTC H
LIN E
3R D CLUTC H
4T H CLUTC H
REVERS E CLUTC H
THROTTL E B
THROTTL E B
THROTTL E B
1ST-HOL D CLUTC H
NO.
71
7 2
90
9 1
9 2
93
9 4
9 5
96
99
X
DESCRIPTIO N O F PRESSUR E
1ST-HOL D CLUTC H
1ST-HOL D CLUTC H
TORQU E CONVERTE R
TORQUE CONVERTE R
TORQUE CONVERTE R
ATF COOLE R
TORQUE CONVERTE R
LUBRICATIO N
TORQUE CONVERTE R
SUCTION
EXHAUS T
14-30
Hydrauli c Flo w — '96 Mode l
Genera l Char t o f Hydrauli c Pressur e
ATF Pum pRegulato r Valv e
Torque Converte r Pressur e
Lubricatio n Pressur e
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Position

(cont'd)
As the engine turns, the ATF pump also starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and dis-

charged into (1). Then, ATF flowing from the ATF pump becomes the line pressure (1). The line pressure (1) is regulated

by the regulator valve. The torque converter inlet pressure (92) enters (94) of the torque converter through the lock-up

shift valve and discharges into (90).

The torque converter check valve prevents the torque converter pressure from rising.

Under this condition, the hydraulic pressure is not applied to the clutches as the manual valve stops line pressure (1).

NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.ProCarManuals.com