lock ACURA TL 1995 Service Service Manual

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
ProCarManuals.com

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
ProCarManuals.com

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 )
ProCarManuals.com

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
ProCarManuals.com

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

Description

Lock-up System

Lock-up Clutch

1. Operation (clutch on)

With the lock-up clutch on, the fluid in the chamber between the torque converter cover and lock-up piston is drained off,

and the converter fluid exerts pressure through the piston against the torque converter cover. As a result, the converter tur-

bine is locked to the converter cover. The effect is to bypass the converter, thereby placing the vehicle in direct drive.

LOCK-UP PISTON

TORQUE CONVERTER

COVER
TURBINE
DAMPER SPRING

To ATF cooler

TURBINE

PUMP

To ATF cooler

INLET
TORQUE CONVERTER

COVER
2. Operation (clutch off)

With the lock-up clutch off, the fluid flows in the reverse of CLUTCH ON. As a result, the lock-up piston moves away from

the converter cover, and the torque converter lock-up is released.
MAINSHAFT
Power flow

The power flows by way of:

Engine

Drive plate

Torque converter cover

Lock-up piston

Damper spring

Turbine

Mainshaft

Power flow

Engine

Drive plate

Torque converter cover

Pump

Turbine

Mainshaft

MAINSHAFTProCarManuals.com

Description

No Lock-up

The pressurized fluid regulated by the modulator works on both ends of the lock-up shift valve and on the left side of the

lock-up control valve. Under this condition, the pressures working on both ends of the lock-up shift valve are equal, and

the shift valve is moved to the right side by the tension of the valve spring alone. The fluid from the pump will flow

through the left side of the lock-up clutch to the torque converter; that is, the lock-up clutch is in OFF condition.

NOTE:

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

The hydraulic circuit shows '97 - '98 models; '96 model is similar.
Lock-up System (cont'd)ProCarManuals.com