1995 ACURA TL sensor

Emission Control System

Exhaust Gas Recirculation (EGR) System

Description

The EGR system is designed to reduce oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the EGR

valve and the intake manifold into the combustion chambers. It is composed of the EGR valve, EGR vacuum control valve,

EGR control solenoid valve, PCM and various sensors.

The PCM contains memories for ideal EGR valve lifts for varying operating conditions. The EGR valve lift sensor detects

the amount of EGR valve lift and sends the information to the PCM. The PCM then compares it with the ideal EGR valve lift

which is determined by signals sent from the other sensors. If there is any difference between the two, the PCM cuts cur-

rent to the EGR control solenoid valve to reduce vacuum applied to the EGR valve.

EGR VALVE

LIFT SENSOR
INTAKE

MANIFOLD

From No. 4 ECU (PCM)

FUSE (15 A) or (20 A)

(in the under-dash

fuse/relay box)

EGR

CONTROL

SOLENOID

VALVE

EGR

VACUUM

CONTROL

VALVE
VARIOUS

SENSORS
EGR VALVEProCarManuals.com

Evaporative Emission (EVAP) Controls

Description

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The

system consists of the following components:

A. Evaporative Emission (EVAP) Control Canister

An EVAP control canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from the

EVAP control canister into the engine and burned.

B. Vapor Purge Control System

EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a port

on the throttle body. The purging vacuum is controlled by the EVAP purge control solenoid valve.

'96 model:
'97 - 98 models:

C. Fuel Tank Vapor Control System

When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and

regulates the flow of fuel vapor to the EVAP control canister.

'96 model:

INTAKE MANIFOLD
THROTTLE

BODY

EVAP PURGE

CONTROL

SOLENOID VALVE

FUEL TANK

EVAP VALVE
EVAP TWO WAY VALVE
From

No. 4 ECU
(PCM) (15A)

FUSE (in the under-dash

fuse/relay box)

EVAP

CONTROL

CANISTER FRESH

AIR
EVAP PURGE

FLOW SWITCH

FUEL FILL CAP
PCM
VARIOUS

SENSORS

FUEL TANK
ENGINE COOLANT TEMPERATURE ABOVE 158°F (70°C)
ENGINE COOLANT TEMPERATURE ABOVE 99°F (37°C)
EVAP PURGE CONTROL SOLENOID VALVE DUTY CON-

TROLLED AFTER STARTING ENGINE
EVAP PURGE CONTROL SOLENOID VALVE OFF AFTER

STARTING ENGINEProCarManuals.com

Emission Contro l Syste m
Evaporativ e Emissio n (EVAP ) Control s (cont'd )
'97 - 9 8 models :
INTAKE
MANIFOL DTHROTTL EBODY
FromNo. 4 EC U (PCM )(20 A ) FUS E
(i n th e under-das h
fuse/rela y box )
EVAP CONTROL CANISTERVENT SHUT VALVE
EVAP TWO WAY VALVE
EVAPCONTROLCANISTER
VARIOU SSENSOR S
EVAP BYPAS SSOLENOI D VALV E
FUEL TAN K
FUE L TAN K
PRESSUR E
SENSO RFUE
L TAN K
EVA P VALV E FUE
L FIL L CA P
PCM
EVA P PURG ECONTRO LSOLENOI D VALV E
EVAP THRE EWAY VALV E
ProCarManuals.com

Description

The automatic transmission is a combination of a 3-element torque converter and a dual-shaft electronically controlled

automatic transmission which provides 4 speeds forward and 1 reverse. The entire unit is positioned in line with the engine.

Torque Converter, Gears and Clutches

The torque converter consists of a pump, turbine, and stator, assembled in a single unit. They are connected to the engine

crankshaft so they turn together as a unit as the engine turns. Around the outside of the drive plate is a ring gear which

meshes with the starter pinion when the engine is being started.

The entire torque converter assembly serves as a flywheel while transmitting power to the transmission mainshaft.

The transmission has two parallel shafts: the mainshaft and the countershaft. The mainshaft is in line with the engine

crankshaft. The mainshaft includes the 1st, 4th and 2nd clutches and gears for 4th, 1st, 2nd and reverse (3rd gear is integral

with the mainshaft). The countershaft includes the 3rd, 1st-hold and reverse clutches, and gears for 3rd, 4th, 1st, 2nd,

reverse and parking. The secondary drive gear is integrated with the countershaft. The gears on the mainshaft are in con-

stant mesh with those on the countershaft. When certain combinations of gears in the transmission are engaged by clutch-

positions.

and
es, power is transmitted from the mainshaft to the countershaft to provide

Electronic Control

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.

Hydraulic Control

The lower valve body assembly includes the main valve body, the secondary valve body, the throttle valve body, the lin-

ear solenoid, the shift control solenoid valves and the ATF passage body. They are bolted on the lower part of the trans-

mission housing. The regulator valve body, the ATF pump body, and the accumulator body are bolted to the torque con-

verter housing.

The main valve body on '96 model contains the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the

4-3 kick-down valve and the Clutch Pressure Control (CPC) valve. The main valve body on '97 model contains the manual

valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the 4-3 kick-down valve and the main orifice control valve.

The secondary valve body on '96 model contains the 3-4 orifice control valve, the 4-3 shift timing valve, the modulator valve

and the accumulator pistons.The secondary valve body on '97 model contains the 3-4 orifice control valve, the 4-3 shift tim-

ing valve, the line pressure control valve, the modulator valve and the accumulator pistons. The throttle valve body

includes the throttle valve which is bolted onto the secondary valve body. The linear solenoid is joined to the throttle valve

body. The regulator valve body contains the regulator valve, the lock-up shift valve and the cooler relief valve. Fluid from

the regulator passes through the manual valve to the various control valves. The ATF pump body contains the lock-up tim-

ing valve, the lock-up control valve and the relief valve. The torque converter check valve is located in the torque converter

housing under the ATF pump body. The accumulator body contains the accumulator pistons. The reverse accumulator and

the 1st-hold accumulator pistons are assembled in the rear cover.

The 1st, 1st-hold, 2nd and reverse clutches receive fluid from their respective feed pipes, and the 3rd and 4th clutches

receive fluid from the internal hydraulic circuit.

Shift Control Mechanism

Input from various sensors located throughout the vehicle determines which shift control solenoid valve the PCM will acti-

vate. Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes a

line to one of the clutches, engaging the clutch and its corresponding gear.

er through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the

mainshaft rotates at the same speed as the engine crankshaft. Together with hydraulic control, the PCM optimizes the tim-

ing of the lock-up mechanism. The lock-up valves control the range of lock-up according to lock-up control solenoid valves

A and B, and throttle valve. When lock-up control solenoid valves A and B activate, modulator pressure changes. The lock-

up control solenoid valves A and B are mounted on the torque converter housing, and are controlled by the PCM.

(cont'd)
Lock-up Mechanism

In
position, in 2nd, 3rd, and 4th, and
position in 3rd, pressurized fluid is drained from the back of the torque convert-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
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Grade Logic Control System

How it works:

The PCM compares actual driving conditions with driving conditions memorized in the PCM, based on the input from the

vehicle speed sensor, throttle position sensor, engine coolant temperature sensor, barometric pressure sensor, brake

switch signal and shift lever position signal, to control shifting while a vehicle is ascending or descending a slope, or

reducing speed.

(cont'd)ProCarManuals.com

PCM CONNECTO R D (22P )
Termina l Numbe r
D1
D 2 to D 5
D6
D7
D 8 to D2 0
D21
D2 2
Signa l
VBU
Descriptio n
Back-up powe r syste m
Measurin g Conditions/Termina l Voltag e
Always batter y voltag e
- se e sectio n 1 1 -
TP S
EC T
Throttl e Positio n (TP ) senso r
signa l inpu t
Engin e Coolan t Temperatur e
(ECT ) senso r signa l inpu t Wit
h ignitio n switc h O N (II ) an d throttl e full y
open : Abou t 4. 8 V
Wit h ignitio n switc h O N (II ) an d throttl e full y
closed : Abou t 0. 1 V
Wit h ignitio n switc h O N (II ) an d dependin g o n
engin e coolan t temperature : Abou t 0. 1 V - 4. 8 V
-se e sectio n 1 1 -
VCC 2
SG2
Sensor s powe r suppl y circui t
Sensor s groun d Wit
h ignitio n switc h O N (II) : Abou t 5 V
PC M CONNECTO R E (26P )
(cont'd )
Termina l Numbe r
E1
E2
Signa l Descriptio
n
Measuring Conditions/Termina l Voltag e
Powe r suppl y circui t fo r shif t an d
lock-u p contro l solenoi d valve s
VBSO L
STOP S WBrak e switc h signa l inpu t
E3
E 4
E5
E 6
E7
E 8
E9
E1 0
E1 1
E1 2SH A
ATP 1
ATP2
ATPD
3
ATPD 4
ATPR
TCSF T
NC
NM
LS +Linea r solenoi d powe r suppl y
positiv e electrod e
Mainshaf t spee d senso r signa l
input
Countershaf t spee d senso r signa l
input
A/T gea r positio n signa l fo r
tractio n contro l outpu t
Shif t contro l solenoi d valv e A
contro l Wit
h ignitio n switc h O N (II) : Batter y voltag e
Wit h ignitio n switc h OFF : 0 V
Wit h ignitio n switc h O N (II ) an d brak e peda l
depressed : Batter y voltag e
Wit h ignitio n switc h O N (II ) an d brak e peda l
released : 0 V
Wit h ignitio n switc h O N (II) : Pulsin g signa l
Dependin g o n vehicl e speed : Pulsin g signa l
Whe n engin e is stopped : 0 V
Dependin g o n vehicl e speed : Pulsin g signa l
Whe n vehicl e is stopped : 0 V
Wit h ignitio n switc h O N (II) : Pulsin g signa l
posi -
posi -
posi -
posi -
posi -A/T gea r positio n switc h
tion signa l inpu t
A/T gea r positio n switc h
tion signa l inpu t
A/T gea r positio n switc h
tio n signa l inpu t
A/ T gea r positio n switc h
tio n signa l inpu t
A/ T gea r positio n switc h
tio n signa l inpu t
position , i n
position : 0 V
4t h gea r i n
position
, i n 2n d an d 3r d gea r i n
position : Batter y voltag e
In
Inposition , i n 1s t gea r i n
position
: Batter y voltag e
I n othe r tha n
Inposition : 0 V
In
In othe r tha n
position
: 0 V
position : Batter y voltag e
In
I n
othe r tha n
position : 0 V
position : Batter y voltag e
position
: Batter y voltag e
I n othe r tha n
position
: 0 V
In
In
I n
position : 0 V
othe r tha n position : Batter y voltag e
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