transmission ACURA RL KA9 1996 Service Owner's Manual

PCM Memory Setting

NOTE: The PCM reset procedure and disconnecting the

battery or the BACK UP RADIO (7.5 A) fuse cancels the

PCM memory for idle control. The following procedure

is needed after the PCM reset procedure and reconnect-

ing the battery or the BACK UP RADIO (7.5 A) fuse.

1. Start the engine. Hold the engine at 3,000 rpm with

no load (in Park or neutral) until the radiator fan

comes on.

2. Let the engine idle for approx. 5 minutes under the

following conditions:

• Transmission in Park or neutral

• A/C switch OFF

• Headlights OFF

• Rear defogger OFFProCarManuals.com

The scan tool indicates Diagnostic Trouble Code (DTC) P0420: Insufficient flow in the Exhaust Gas Recirculation

(EGR)
system.

Description

Deterioration (clogging, leakage, etc.) in the EGR line or EGR valve is detected by means of the changes in manifold abso-

lute pressure before and after the operation of the EGR valve.

If deterioration has been detected during two consecutive driving cycles, the MIL will come on and DTC P0401 will be

stored.

Possible Causes

• Clogging, leakage in the EGR line

• Faulty EGR valve

Troubleshooting Flowchart

Is DTC P0401 indicated?
Intermittent failure, system is OK

at this time.

YES

Clean the intake manifold EGR

port and EGR passage with car-

buretor cleaner.

Clean the passage inside the

EGR valve with carburetor

cleaner or replace the valve.
NO
Problem verification:

1. Do the PCM Reset Procedure.

2. Connect the ACS service con-

nector.

3. Test-drive under the following

conditions.

— Without any electrical load

— Transmission in posi-

tion

— Decelerate from 55 mph

(88 km/h) for at least 5 sec-

onds.
The MIL has been reported on.

DTC P0401 is stored.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

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

Lower Valve Body Assembly

The lower valve body assembly is located on the bottom of the transmission housing. The lower valve body assembly

consists of the main valve body, the secondary valve body and the ATF passage.

Main Valve Body

The main valve body houses 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 primary functions of the main valve body are to switch fluid pressure on and

off and to control the hydraulic pressure going to the hydraulic control system.

Secondary Valve Body

The secondary valve body is located on the main valve body. The secondary valve body houses the line pressure control

valve, the modulator valve, the 3-4 orifice control valve, the 4-3 shift timing valve, the 1st accumulator piston and the 2nd

accumulator piston. The shift solenoid valves A and B are assembled on the secondary valve body.

Throttle Valve Body/A/T Clutch Pressure Control Solenoid Valve

The throttle valve body is joined with the A/T clutch pressure control solenoid valve which is controlled by the PCM. The

throttle valve body/A/T clutch pressure control solenoid valve is located on the secondary valve body. The throttle valve

body houses the throttle valve.

LINE PRESSURE

CONTROL VALVE

A/T CLUTCH PRESSURE CONTROL

SOLENOID VALVE

SHIFT SOLENOID

VALVE B

SHIFT SOLENOID

VALVE A

MODULATOR VALVE

1ST ACCUMULATOR

PISTON

SECONDARY VALVE

BODY

MAIN VALVE BODY

MANUAL VALVE

MAIN ORIFICE CONTROL VALVE
THROTTLE VALVE BODY

THROTTLE VALVE

2ND ACCUMULATOR

PISTON

3-4 ORIFICE CONTROL

VALVE

4-3

SHIFT TIMING VALVE

4-3 KICK-DOWN

VALVE

3-4 SHIFT VALVE

2-3 SHIFT VALVE

1-2 SHIFT VALVEProCarManuals.com

Position

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.

• The hydraulic circuit is for '96 - '98 models. On '99 - 01 models, the 2nd accumulator is different.ProCarManuals.com

Park Mechanism

The park mechanism locks the transmission by engaging the park pawl with the park gear which is splined to the counter-

shaft.

Shifting to [3 position causes the park cone (installed at the end of the park rod) to press the park pawl onto the park gear.

Even if the end of the park pawl rides on top of the park gear teeth, slight movement of the countershaft will cause the

park pawl and the park gear to mesh with each other completely because the park cone receives tension from the park rod

spring. The park pawl receives the tension (which acts to separate the park pawl from the park gear) from the park pawl

spring.

COUNTERSHAFT

PARK ROD SPRING

PARK PAWL
PARK GEAR

PARK ROD HOLDER

PARK CONEProCarManuals.com

Component Locations

POWERTRAIN CONTROL

MODULE (PCM)

SHIFT LOCK

SOLENOID

PARK PIN

SWITCH

COUNTERSHAFT

SPEED SENSOR

TORQUE CONVERTER CLUTCH

(LOCK-UP CONTROL)

SOLENOID VALVES A AND B
MAINSHAFT SPEED SENSOR

SHIFT SOLENOID

VALVES A AND B

(Located in transmission.)

VEHICLE SPEED

SENSOR (VSS)

A/T CLUTCH PRESSURE

CONTROL SOLENOID VALVE

(Located in transmission.)
TRANSMISSION

RANGE SWITCH

A/T GEAR POSITION

SWITCHProCarManuals.com

From pag e 14-6 8
Chec k Shif t Solenoi d Valv e A fo r
a Shor t Circuit :
1 . Remov e th e shif t cabl e cove r
fro m th e transmission .
2. Disconnec t th e shif t solenoi dvalve/A/ T clutc h pressur e con -
tro l solenoi d valv e harnes s 4- P
connector .
3. Chec k fo r continuit y betwee nthe E1 2 an d A2 6 terminals .
Is ther e continuity ?
Measur e Shif t Solenoi d Valv e A
Resistanc e a t th e Solenoi d
Connector :
Measur e th e resistanc e betwee n
the No . 2 termina l o f th e shif tsolenoi d valve/A/ T clutc h pressur e
contro l solenoi d valv e harnes s 4 P
connecto r an d bod y ground .
Is th e resistanc e 12-2 5
Chec k th e V B SO L Voltage :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Measur e th e voltag e betwee n
th e E 1 an d A2 6 terminals .
I s ther e voltage ? Repai
r shor t t o groun d in th e wir e
betwee n th e E1 2 termina l an d th e
shif t solenoi d valv e A .
Chec k fo r ope n i n th e wir e
betwee n th e E1 2 termina l an d th e
shif t solenoi d valv e A .
Chec k fo r ope n i n th e wir e
betwee n th e E 1 termina l an d th e
under-hoo d fuse/rela y box . PC
M CONNECTOR S
Wir e sid e o f femal e terminal s
SHIF T SOLENOI D
VALVE/A/ T CLUTC H PRESSUR E
CONTRO L SOLENOI D
VALV E HARNES S 4P CONNECTO R
Termina l sid e o f
mal e terminal s
PC M CONNECTOR S
Wir e sid e o f femal e terminal s
Replac e th e shif t solenoi d valve s
A an d B .
ProCarManuals.com

From pag e 14-7 0
Chec k Shif t Solenoi d Valv e B fo r
a Shor t Circuit :
1 . Remov e th e shif t cabl e cove r
fro m th e transmission .
2 . Disconnec t th e shif t solenoi d
valve/A/ T clutc h pressur e con -
tro l solenoi d valv e harnes s 4 P
connector .
3 . Chec k fo r continuit y betwee n
th e E2 5 an d A2 6 terminals .
I s ther e continuity ?
Measur e Shif t Solenoi d Valv e B
Resistanc e a t th e Solenoi d
Connector :
Measur e th e resistanc e betwee n
th e No . 1 termina l o f th e shif t
solenoi d valve/A/ T clutc h pres -
sur e contro l solenoi d valv e har -
nes s 4 P connecto r an d bod y
ground .
Is th e resistanc e 12-2 5
Replac e th e shif t solenoi d valve s
A an d B .
Repai r shor t t o groun d in th e wir ebetwee n th e E2 5 termina l an d th eshif t solenoi d valv e B .
Chec k fo r ope n i n th e wir e
betwee n th e E2 5 termina l an d
th e shif t solenoi d valv e B .
Chec k fo r ope n i n th e wir e
betwee n th e E 1 termina l an d th e
under-hoo d fuse/rela y box . PC
M CONNECTOR S
SHIF T SOLENOI D
VALVE/A/ T CLUTC H PRESSUR E
CONTRO L SOLENOI D VALV E
HARNES S 4 P CONNECTO R
Termina l sid e o f
mal e terminal s
PC M CONNECTOR S
Wir e sid e o f femal e terminal s
Chec
k th e V B SO L Voltage :
1. Tur n th e ignitio n switc h O N (II) .2. Measur e th e voltag e betwee n
th e E l an d A2 6 terminals .
I s ther e voltage ?
ProCarManuals.com