1996 ACURA RL KA9 engine

Evaporative Emissio n (EVAP ) Control s
Descriptio n
Th e evaporativ e emissio n control s ar e designe d t o minimiz e th e amoun t o f fue l vapo r escapin g t o th e atmosphere . Th e
syste m consist s o f th e followin g components :
A . Evaporativ e Emissio n (EVAP ) Caniste r
A n EVA P caniste r i s use d fo r th e temporar y storag e o f fue l vapo r unti l th e fue l vapo r can be purge d fro m th e EVA P
caniste r int o th e engin e an d burned .
B . Vapo r Purg e Contro l Syste m
EVA P caniste r purgin g is accomplishe d b y drawin g fres h ai r throug h th e EVA P caniste r an d int o a por t o n th e throttl e
body . Th e purgin g vacuu m is controlle d b y th e EVA P caniste r purg e valve .
EVA P CANISTE R PURG E VALV E DUT Y CONTROLLE D AFTE R START -
IN G ENGIN E
*: '9 6 - 9 9 model s*1: '0 0 - 0 1 model sC. Fue l Tan k Vapo r Contro l Syste m
Whe n fue l vapo r pressur e in th e fue l tan k is highe r tha n th e se t valu e o f th e EVA P tw o wa y valve , th e valv e open s an d
regulate s th e flo w o f fue l vapo r t o th e EVA P canister .
Durin g refueling , th e fue l tan k vapo r contro l valv e open s wit h th e pressur e in th e fue l tank , an d feed s th e fue l vapo r t o
th e EVA P canister .
'96 - 9 9 models :
FUELTANKPRESSURESENSOR
EVAPTWO WAYVALVE
FUEL TANKEVAP VALVE
FUEL TAN K
EVAP CANISTE RPURGE VALV E
EVAPBYPAS SSOLENOI DVALVE
EVAPCANISTE RVENT SHU T VALV EEVAP CONTRO LCANISTER
EVAPTHRE EWAYVALV E
FUEL FIL LCAP
Fro mNo. 2 0 EC U (PCM )(20 A ) FUS E(in th e under-das hfuse/relay box )
VARIOU SSENSOR S
ENGINE COOLAN T TEMPERATUR E ABOV E 99° F (37°C) * 140° F (60°C)*1
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 park. The secondary drive gear is integrated with the countershaft. The gears on the mainshaft are in constant

mesh with those on the countershaft. When certain combinations of gears in the transmission are engaged by clutches,

power is transmitted from the mainshaft to the countershaft to provide , , , and positions.

Electronic Control

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a A/T clutch pressure control 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

solenoid, the shift solenoid valves and the ATF passage body. They are bolted on the lower part of the transmission hous-

ing. Other valve bodies, the regulator valve body, the ATF pump body and the accumulator body, are bolted to the torque

converter housing.

The main valve body 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 contains the 3-4 orifice control valve, the 4-3 shift timing

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 A/T clutch pressure control 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 timing 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 accu-

mulator 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 solenoid valve the PCM will activate.

Activating a shift 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.

Lock-up Mechanism

In position, in 2nd, 3rd, and 4th, and position in 3rd, pressurized fluid is drained from the back of the torque con-

verter 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 opti-

mizes the timing of the lock-up mechanism. The lock-up valves control the range of lock-up according to torque converter

clutch (lock-up control) solenoid valves A and B, and throttle valve. When torque converter clutch (lock-up control)

solenoid valves A and B activate, modulator pressure changes. The torque converter clutch (lock-up control) solenoid

valves A and B are mounted on the torque converter housing, and are controlled by the PCM.ProCarManuals.com

Position

The power flow when decelerating is as follows:

1. Rolling resistance from the road surface goes through the front wheels to the secondary drive gear, then to the counter-

shaft 1st gear via the 1st-hold clutch which is applied during deceleration.

2. The 1st gear one-way clutch disengages at this time because the application of torque is reversed.

3. The counterforce conveyed to the countershaft 1st gear turns the mainshaft 1st gear. At this time, since hydraulic pres-

sure is also applied to the 1st clutch, counterforce is also transmitted to the mainshaft. As a result, engine braking can

be obtained with 1st gear.

TORQUE CONVERTER

1ST CLUTCH MAINSHAFT 1ST GEAR

MAINSHAFT

SECONDARY

DRIVE GEAR
COUNTERSHAFT

COUNTERSHAFT

1ST GEAR

SECONDARY DRIVEN GEAR
1ST-HOLD

CLUTCHProCarManuals.com

Position

The power flow when decelerating is as follows:

1. Rolling resistance from the road surface goes through the front wheels to the secondary drive gear, then to the counter-

shaft 1st gear via the Ist-hold clutch which is applied during deceleration.

2. Power transmitted to the countershaft 1st gear is conveyed via the 1st gear one-way clutch on the inside of the counter-

shaft 1st gear to the countershaft 2nd gear. The 1st gear one-way clutch is used to drive the countershaft 2nd gear.

3. The 2nd gear one-way clutch disengages at this time because the application of torque is reversed.

4. The counterforce conveyed to the countershaft 1st gear turns the mainshaft 2nd gear. At this time, since hydraulic pres-

sure is applied to the 2nd clutch, counterforce is transmitted to the mainshaft. As a result, engine braking can be

obtained with 2nd gear.

TORQUE CONVERTER

MAINSHAFT

2ND GEAR
2ND CLUTCH

MAINSHAFT

SECONDARY

DRIVE GEAR
COUNTERSHAFT

1ST GEAR

ONE-WAY CLUTCH

COUNTERSHAFT

1ST GEAR

SECONDARY DRIVEN GEAR
1ST-HOLD

CLUTCH
COUNTERSHAFT

2ND GEARProCarManuals.com

Electronic Control System

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a A/T clutch pressure control

solenoid and four solenoid valves. Shifting and lock-up are electronically controlled for comfortable driving under all con-

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

PCM

Throttle Position Sensor

Signal

Engine Coolant Temperature

Sensor Signal

Indicator Light

Self-Diagnosis Signal
PGM-FI

Control System

Shift Control

Lock-up Control

A/T Control System

Self-Diagnosis

Function
Vehicle Speed Sensor

Signal

Service Check Connector

Shift Solenoid

Valve A

Shift Solenoid

Valve B

A/T Clutch Pressure Control

Solenoid Valve

Torque Converter Clutch

(Lock-up Control)

Solenoid Valve A

Torque Converter Clutch

(Lock-up Control)

Solenoid Valve B

Mainshaft Speed Sensor

Signal

Countershaft Speed

Sensor Signal
Interlock SystemProCarManuals.com

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

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

slope.ProCarManuals.com

Description

Electronic Control System (cont'd)

Ascending Control

When the PCM determines that the vehicle is climbing a hill in position, the system extends the engagement area of

3rd gear to prevent the transmission from frequently shifting between 3rd and 4th gears, so the vehicle can run smooth

and have more power when needed.

NOTE:

• Shift schedules between 3rd and 4th gear stored in the PCM enable the PCM's fuzzy logic to automatically select the

most suitable gear according to the magnitude of a gradient.

• Fuzzy logic is a form of artificial intelligence that lets computers respond to changing conditions much like a human

mind would.

Descending Control

When the PCM determines that the vehicle is going down a hill in position, the shift-up speed from 3rd to 4th gear

when the throttle is closed becomes faster than the set speed for flat road driving to widen the 3rd gear driving area.

This, in combination with engine braking from the deceleration lock-up, achieves smooth driving when the vehicle is

descending. There are two descending modes with different downshift (4-3) schedules according to the magnitude of a

gradient stored in the PCM. When the vehicle is in 4th gear, and you are decelerating on a gradual hill, or when you are

applying the brakes on a steep hill, the transmission will downshift to 3rd gear. When you accelerate, the transmission will

then return to 4th gear.

ASCENDING MODE

DESCENDING MODE

3RD/4TH SHIFTING

CHARACTERISTICS

CONTROL AREA
Flat road

mode

Steep descending

mode

Gradual descending

modeProCarManuals.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 A/T clutch pressure control

solenoid valve.

The shift solenoid valves A and B are bolted on the secondary valve body. The torque converter clutch (lock-up control)

solenoid valves A and B are bolted on the outside of the torque converter housing.

ATF PUMP BODY

ACCUMULATOR BODY

SHIFT SOLENOID

VALVE B

SHIFT SOLENOID

VALVE A

REAR COVER

REGULATOR VALVE

BODY

THROTTLE VALVE BODY

SECONDARY VALVE BODY

ATF PASSAGE
MAIN VALVE BODY
Hydraulic ControlProCarManuals.com