1996 ACURA RL KA9 parking brake

Troubleshooting Precautions

ABS Indicator Light:

The ABS indicator light comes on for 3 seconds and then goes off when the control unit detects no problem during the ini-

tial diagnosis right after the engine starts. However, the ABS indicator light can stay on for up to 40 seconds when the

control unit starts to check for pump overrun, etc. during the initial diagnosis. The ABS indicator light comes on, and the

ABS control unit memorizes the diagnostic trouble code (DTC) under certain conditions.

The parking brake is applied for more than 30 seconds while the vehicle is being driven. (DTC 2-1)

The transmission downshifted excessively. (DTC 4-1, 4-2)

The vehicle loses traction, and the front wheels spin for more than 1 minute when starting from a stuck condition on a

muddy, snowy, or sandy road. (DTC 4-8)

Tire adhesion is lost due to excessive cornering speed. (DTC 5, 5-4, 5-8)

The vehicle is driven on an extremely rough road. (DTC 8-1)

The vehicle is interfered by strong radio waves (noise), for example, illegal radio, etc. (DTC 8-2)

NOTE: If there is any trouble in the system, the ABS indicator light comes on during driving.

Diagnostic Trouble Code (DTC):

When the control unit detects a problem and the ABS indicator light comes on, the control unit memorizes the DTC.

The control unit has three memory registers. When a problem occurs, the control unit stores the DTC in the first memory

register. If another problem occurs, or the same problem occurs again, the control unit moves the first DTC to the next

memory register, and stores the second DTC in the first register. If there's a third problem occurrence, the two existing

DTCs are moved up one register, and the third DTC is stored in the first register. If problems continue to occur, the oldest

problem is moved out of the last register and lost, and the most recent problem is stored in the first register. When the

same problem occurs three times, the same DTC is stored in all memory registers. (Refer to the Symptom-to-System

Chart for diagnostic period.)

The most recent DTC is indicated first, and the oldest DTC is indicated last.

The DTCs are erased from the control unit when the ABS control unit +B2 power supply or connector is disconnected.

The control unit's memory can be erased by disconnecting the ABS B2 fuse for more than 3 seconds.

Self-diagnosis:

There are three self-diagnoses described below.

Initial diagnosis: Performed right after the engine starts until the ABS indicator light goes off.

Regular diagnosis: Continuously performed (under some conditions) after the ABS indicator light goes off until the

engine stops.

Individual part/system diagnosis: Diagnosis about a specific part/system under its operating conditions.

The CPU (central processing unit) controls the following when it detects a problem during self-diagnosis:

Turns the ABS indicator light ON.

Turns the front and rear fail-safe relays off.

Stops the ABS control.

Stops the ABS pump. (The pump may work under some conditions.)

After the DTC is stored in the control unit, the CPU stops self-diagnosis.ProCarManuals.com

Troubleshooting
DTC 5 , 5-4 , 5-8 : Rea r Whee l Loc k
The AB S contro l uni t monitor s th e rea r whee l senso r signal s durin g th e regula r diagnosi s (durin g driving) . Thi s diagnosi s
is no t performe d whe n th e parkin g brak e signa l i s ON . Th e AB S contro l uni t turn s th e AB S indicato r ligh t o n if i t detect s n o
signal(s ) fro m th e rea r whee l sensor(s ) du e to , fo r example , rea r whee l lock .
Possibl e causes :
Wheel spi n durin g cornerin g
Open circuit , interna l shor t o r shor t t o th e bod y groun d in th e whee l senso r syste m
Rear brak e dra g
Modulato r doe s no t decreas e pressur e properl y
Faulty AB S contro l uni t
— Whe n vehicl e i s driven , ABSindicato r ligh t i s ON .— Wit h th e SC S servic e connec -tor connecte d (se e pag e 19-40 ),DTC s 5 , 5- 4 and/o r 5- 8 ar e indi -
cated .
Chec k th e PAR K circuit :
1. Tur n th e ignitio n switc h O N (II) .2. Pres s th e parking brake pedal .
Doe s th e brak e syste m ligh t
com e on ? Parkin
g brak e switc h stuc k OFF .
Repai r ope n circui t betwee n th e
under-das h fuse/rela y bo x an d
parkin g brak e switch .
NOTE:The self-diagnosi s o f th e whee l senso r i s per -forme d i n thi s step .
Test-driv e wit h th e parkin g brak e released .
Does th e AB S indicato r ligh tcom e on ?
Chec k fo r rea r brak e drag :
1 . Rais e th e rea r o f th e vehicle ,
and suppor t i t wit h safet ystands (se e sectio n 1 ).2 . Spi n th e lef t and/o r righ t rea rwhee l an d chec k fo r brak e
drag . I
s cod e 4- 4 o r 4- 8 indicated ?
Perform th e troubleshootin g fo rthe rea r whee l sensor .
Perfor m th e appropriat e trouble -
shootin g fo r th e code .
Doe s th e brak e drag ?
Repair th e rea r brak e drag .
Check th e AB S functio n (se epage 19-95 ).
Th e probabl e caus e wa s tha t
tractio n wa s los t du e t o exces -
siv e cornerin g speed , etc .
Chec
k th e self-diagnosis :
Test-driv e th e vehicl e a t speed s
of 6 mp h (1 0 km/h ) o r more .
Confir m th e DT C (se e pag e 19-40 ).
ProCarManuals.com

ABS Contro l Uni t Termina l Arrangemen t
ABS CONTRO L UNI T 22 P CONNECTO R
Wir e sid e o f femal e terminal s
Terminal
number
1
3
4
5
6
7
8
9
10
1 1
Wir e
colo r
BLK
WHT/RED *
GRN/RED
WHT/GRN *
BRN
GRN/BL U
GRN
GRN/BL K
GRN/WH T
YEL/BLK
Termina l sig n
(Termina l
name)
GND3
(Groun d 3 )
FL P
(Front-lef t
pulse )
PARK
(Parking )
FRP
(Front-righ t
pulse)
FLW (-)
(Front-lef t
wheel negative )
FLW (+ )
(Front-lef t
wheel positive )
FRW (-)
(Front-righ t
wheel negative )
FRW (+ )
(Front-righ t
wheel positive )
STOP
IG2
(Ignitio n 2 )
Descriptio n
Ground
Output s left-fron t whee l
senso r signa l
Detect s parkin g brak e
switc h signa l
Output s right-fron t whee l
senso r signa l
Detect s left-fron t whee l
senso r signa l
Detect s right-fron t whee l
senso r signa l
Detect s brak e peda l posi -
tion switc h signa l
Power sourc e fo r activatin g
the syste m
Measuremen t
Terminal
1-GND
3-GN D
4-GN D
5-GND
6-7
8- 9
10-GN D
11-GND
Condition s
(Ignition switch ON (ID )
Spi n whee l slowl y
Parkin g brak e Presse d
pedal Release d
Spin whee l slowl y
Spin whee l a t
1 turn/secon d
Stoppe d
Brake Presse d
pedal Release d
Ignition O N (II )
switc h Star t (III )
Voltag e
Below 0. 3 V
5 V 0 V
Below 0. 3 V
Batter y Voltag e
5V 0 V
AC:
0.05 3 V or
abov e
(Reference )
Oscilloscope :
0.15Vp-p o r
abov e
0.25-1 . 15 V
Batter y Voltag e
Belo w 0. 3 V
Batter y Voltag e
Below 0. 3 V
*: Wit h TC S onl y
ProCarManuals.com

TCS CONTROL UNIT 20P CONNECTOR

Wire side of female terminals

VB: Battery Voltage

Terminal

number

1

2

4

5

6

9

10

11

12

13

14

15

16

17

20
Wire

color

BLK/YEL

GRN/RED

BLU

PNK/BLU

BLK/WHT

BLK

BRN/WHT

GRN/WHT

BLU

GRN/ORN

BLK/ORN

BRN/BLK

WHT/BLU

BLU/GRY

GRN

BRN
Terminal sign

(Terminal name)

IG1

(Ignition 1)

PARK

(Parking)

SCS

(Service check

signal)

STR-GND

(Steering ground)

AT-SHIFT

(AT shift)

FSR

(Fail-safe relay)

PMG

(Power motor

Ground)

VPM

(Voltage power

motor)

STOP

(Stop)

NEP (Engine

speed pulse)

BARO

(Barometric)

TC-FC

(Traction control

fuel cut)

LG2

(Logic ground 2)

STR-VCC (Steer-

ing power supply)

WARN2

(Warning 2)

SH-MOT

(Shield motor)

MOT +

(Motor +)

MOT-

(Motor -)
Description

Detects ignition switch

IG1 signal

Detects parking brake

switch signal

Detects service check

connector signal

(Diagnostic trouble

code indication)

Ground for the steering

angle sensor

Detects A/T shift posi-

tion signal

Drives fail-safe relay

Power ground for the

TCS control valve

actuator motor

Power source for the

TCS control valve

actuator motor

Detects brake pedal

position switch signal

Detects engine speed

signal

Detects barometric

sensor signal

TCS Fl, Fuel cut

(torque down) signal

Ground for the logic

circuit

Power source for the

steering angle sensor

Drives TCS indicator light

(The indicator light comes

on by the self-bias)

Shield for the TCS con-

trol valve actuator motor

Drives TCS control

valve actuator motor

Drives TCS control

valve actuator motor
Measurement

terminals

1-GND

2

3-GND

4-GND

5-GND

6-GND

9-GND

10-GND

11-GND

12-GND

13-GND

14-GND

15-GND

16-GND

17-GND

19-20

20-19
Voltage

Conditions

(Ignition Switch ON (II))

Depress the parking

brake pedal.

Release the parking

brake pedal.

SCS service connector

connected.

SCS service connector

disconnected.

Shift the transmission

to position, then

start the engine.

Start the engine.

Start the engine.

Brake pedal depressed.

Brake pedal released.

Engine idling

TCS is functioning,

(maximum fuel cut)

TCS is not functioning.

Indicator light ON

Indicator light OFF

TCS is functioning.

TCS is not functioning.

TCS is functioning.

TCS is not functioning.
Output

voltage

VB

Below 0.6 V

VB

0V

5V

Below 0.3V

About 4V

(5V 0V)

VB

1.5V

Below 0.3 V

0V

VB

VB

0V

About 6V

(12V
0V)

About 3 V

About 1.5V

About 4.5 V

(5 V,
PWM)

Below 0.3V

About 5 V

About 2 V

VB

VB

0V

VB

0VProCarManuals.com

Troubleshooting Precautions

1. In any of these cases, the TCS indicator light may come on or stay on even the TCS system is normal.

The coolant temperature is 32°F (0°C) or below.

The parking brake is applied for more than 30 seconds while the vehicle is being driven.

The tires are not inflated to the specified pressure.

The wheel sensor signal is interrupted during driving at speeds of 6 mph (10 km/h) or above due to, for example, a

vehicle spinning.

The MAP sensor, the coolant temperature sensor, the ICM or the atmospheric pressure sensor system of the PGM-FI

system is faulty.

2. TCS does not function when the TCS indicator light is ON.

3. When both the TCS indicator light and the MIL are ON, troubleshoot the PGM-FI system first.

4. When both the TCS indicator light and the ABS indicator light are ON, troubleshoot the ABS first.

5. The DTC 4-9 (ABS down) is memorized when the ABS control unit cannot output the wheel speed signal due to, for

example, a missing or blown ABS B2 (15 A) fuse. If you fail to erase the DTC of the TCS after troubleshooting the ABS,

the DTC remains in the TCS control unit memory. Therefore, be sure to test-drive the vehicle, and check the TCS indica-

tor light before starting to troubleshoot the TCS.ProCarManuals.com

Diagnostic Trouble Code (DTC)

DTC Erasure

1. Press the parking brake pedal.

2. Push and hold the TCS switch, then turn the ignition switch ON (II).

3. Hold the TCS switch pushed for 4 to 6 seconds, then release the TCS switch.

4. After 3 seconds, the TCS indicator light should go off and blink 2 times, then stay on. This means that the DTC is

erased.

NOTE:

Always follow these steps exactly. If you connect the SCS service connector and/or release the parking brake pedal dur-

ing these steps, the DTC will not be erased.

If the TCS indicator light blinks repeatedly, replace the TCS control unit.

Standard Indication Pattern

Abnormal Indication Pattern

Light blinks repeatedlyProCarManuals.com

Troubleshooting

Brake System Indicator Does Not Go Off

Check the ABS:

1. Turn the ignition switch.

2. Check the ABS indicator.

Does the ABS indicator stay on?
Perform the troubleshooting for

the
DTC.

Release the parking brake.

Does the brake system indica-

tor go off?
The system is OK at this time.

Check the brake fluid level.

Is the level OK?
Refill the brake fluid, then confirm

that the brake system indicator

goes off.

Check the VSA control unit:

1. Turn the ignition switch OFF.

2. Disconnect the VSA control

unit 42P connector.

3. Turn the ignition switch ON (II).

Does the brake system indica-

tor go off?
Replace the VSA modulator-

control unit.

Repair short to body ground in

the wire between the brake

system indicator and the VSA

control unit.

The parking brake switch stuck

ON.

The brake fluid level switch

stuck ON.ProCarManuals.com

Precharge Brake Line Bleeding

1. Connect the SCS service connector to the service check connector (2P) under the glove box.

2. Press the parking brake pedal.

3. Press the VSA off switch, and hold it.

4. Turn the ignition switch ON (II).

5. Release the VSA off switch after the VSA activation indicator goes off twice.

6. Press the VSA off switch after the VSA activation indicator comes on.

7. Release the VSA off switch after the VSA activation indicator goes off.

8. Press the VSA off switch after the VSA activation indicator starts blinking.

9. Release the VSA off switch after the VSA activation indicator stops blinking.

10. Turn the ignition switch OFF, then repeat steps 2 through 10 for 4 times.ProCarManuals.com