1996 ACURA RL KA9 engine

Troubleshooting
DTC 7-4 : Rea r Solenoi d
During th e initia l diagnosis , afte r th e fail-saf e relay s ar e turne d on , an d durin g th e regula r diagnosis , th e AB S contro l uni t
monitor s th e voltag e fro m th e batter y fo r th e si x solenoid s (whe n th e AB S is no t functioning) . I f th e detectio n circui t fo r
the rea r solenoid s detect s 0 V , th e AB S contro l uni t keep s th e AB S indicato r ligh t o n afte r th e engin e is started . I t turn s th e
AB S indicato r ligh t o n agai n if i t detect s 0 V afte r th e ligh t goe s off .
Possibl e causes :
Rear fail-saf e rela y stuc k OF F
Ope n circui t i n th e rea r solenoi d driv e circuit s betwee n th e under-hoo d fuse/rela y bo x an d AB S contro l uni t
Shor t circui t t o bod y groun d in th e rea r solenoi d driv e circuit s betwee n th e solenoid s an d AB S contro l uni t
Fault y rea r solenoi d driv e transisto r (ON ) i n th e AB S contro l uni t
The AB S contro l uni t momentaril y output s th e O N signa l t o eac h solenoi d (to o momentar y to tur n th e solenoi d on ) durin g
the initia l diagnosis , an d eac h tim e th e vehicl e is driven , t o chec k th e voltag e fro m th e batter y wit h th e detectio n circuit . I f
th e detectio n circui t fo r th e rea r solenoid s detect s batter y voltag e a t thi s time , th e AB S contro l uni t keep s th e AB S indica -
to r ligh t on . I t turn s th e AB S indicato r ligh t o n agai n if i t detect s th e batter y voltag e whe n th e vehicl e i s driven .
Possibl e causes :
Short circui t t o powe r i n th e rea r solenoi d driv e circuit s betwee n th e solenoid s an d AB S contro l uni t
Fault y rea r solenoi d driv e transisto r (OFF ) i n th e AB S contro l uni t
Shor t circui t t o powe r i n th e rea r solenoi d driv e circuit s in th e modulato r wir e harnes s o r solenoid s
Shor t circui t t o th e rea r solenoi d outle t circui t i n th e inle t circui t betwee n th e solenoid s an d AB S contro l uni t
Shor t circui t t o th e right-fron t o r left-fron t solenoi d inle t o r outle t circui t i n th e rea r solenoi d inle t o r outle t circui t
betwee n th e solenoid s an d AB S contro l uni t
Doe s th e AB S indicato r ligh t g ooff ?
Th e syste m is O K a t thi s time .Check th e wir e harnes s an d con -nector s betwee n th e AB S contro lunit, fail-saf e rela y an d modulato runit (intermitten t ope n o r shor tcircuit) .
Is cod e 7- 4 indicated ?Perform th e appropriat e trouble -shooting fo r th e code .
(To pag e 19-87 )
Confir m th e DT C tha t appear s first .
Proble m verification :Start th e engine .
With engin e running , AB S indi -cato r ligh t i s ON .With th e SC S servic e connec -tor connecte d (se e pag e19-40 ), DT C 7- 4 is indicated .
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Troubleshooting
DTC 8-2 : CPU , DT C 8-4:I C
DTC 8-2 : CPU
The AB S contro l uni t check s th e dat a o f th e tw o CPU s b y comparison , an d i t keep s th e AB S indicato r ligh t o n i f ther e ar e
an y difference s i n th e dat a betwee n th e CPUs . I t turn s th e AB S indicato r ligh t o n agai n i f i t detect s an y differenc e afte r th e
ligh t goe s off .
Doe s th e AB S indicato r ligh t
com e on ?
Is cod e 8- 2 indicated ?
The syste m is O K at thi s time .
Perfor m th e appropriat e trou -
bleshootin g fo r th e code .
DTC 8-4:I C (Integrate d Circuit )
Th e AB S contro l uni t check s th e interna l IC s durin g th e initia l diagnosi s an d regula r diagnosis , an d i t keep s th e AB S indicato r
ligh t o n if i t detect s an y abnormality . I t turn s th e AB S indicato r ligh t o n agai n if i t detect s any abnormalit y afte r th e ligh t goe s off .
Replac e th e AB S contro l uni t i f DT C 8- 4 is indicate d wit h th e SC S servic e connecto r connecte d (se e pag e 19-40 ).
Wit h engin e running , AB S indi -cato r ligh t i s ON .With th e SC S servic e connec -
to r connecte d (se e pag e 19-40 ),
DT C 8- 2 is indicated .
Problem verification :Start th e engine .
Confirm th e DT C (se e pag e 19-40 ).
Replac e th e AB S contro l unit .
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Modulator Uni t
High-Pressur e Brak e Flui d Replacement/Bleedin g
Replacement
1. Reliev e syste m pressur e (se e pag e 19-97 ). Leav e th e
tub e an d wrenc h o n th e maintenanc e bleeder , an d
leav e th e tub e in th e container .
2 . Star t th e engin e t o operat e th e pum p motor .
NOTE:
If th e pum p moto r operate s fo r 4 0 second s o r
more , th e AB S indicato r ligh t come s on , an d th e
pum p moto r stops . Sto p an d restar t th e engin e t o
operat e th e pum p moto r again .
I f th e AB S indicator light come s on , remov e th e
AB S B 2 (1 5 A ) fus e fo r 3 second s o r mor e t o
eras e th e DT C afte r servicing .
3 . Repea t step s 1 an d 2 to drai n th e res t o f th e brak e
fluid fro m th e modulato r unit .
NOTE : Th e modulato r ha s a capacit y o f approxi -
mately 15 0 (5. 0 fl-oz , 5. 3 Imp-oz) . Approximatel y
35 - 4 5 (1. 2 - 1. 5 fl-oz , 1. 2 - 1. 6 Imp-oz ) o f th e flui d
i s draine d eac h tim e yo u reliev e syste m pressure .
4 . Remov e th e cap , an d refil l th e reservoi r t o th e MA X
(upper ) leve l wit h fres h brak e fluid .
NOTE : Pou r th e brak e flui d slowl y s o tha t i t doe s
not foam , an d wai t fo r a fe w minutes .
5. Repea t step s 1 an d 2 twice , an d refil l th e reservoi r
t o th e MA X (upper ) leve l wit h fres h brak e fluid .
6 . Tighte n th e maintenanc e bleede r t o th e specifie d
torque .
7 . Star t th e engine , an d mak e sur e tha t th e AB S indica -
tor ligh t goe s off .
Bleedin g
Whe n th e brak e flui d i s completel y draine d fro m th e
reservoi r (ai r enter s th e modulato r unit) , blee d th e ai r
from th e modulato r a s follows :
1 . Fil l th e reservoi r t o th e MA X (upper ) leve l wit h fres h
brake fluid .
2. Connec t a tub e t o th e maintenanc e bleede r o n th e
modulato r unit , an d se t th e othe r en d o f th e tub e in a
suitabl e containe r (se e pag e 19-97 ).
3 . Loose n th e bleeder , an d star t th e engin e t o operat e
th e pum p motor .
4 . Tighte n th e bleede r whe n th e flui d start s t o flo w ou t
o f th e bleeder .
NOTE : Tak e car e no t t o spil l th e brak e flui d fro m
th e container .
5 . Sto p th e engin e afte r th e pum p moto r stops .
NOTE : I f th e AB S indicato r ligh t come s o n an d th e
pum p moto r stops , restar t th e engin e an d repea t step s
3 throug h 5 above .
19-98ProCarManuals.com

Self-diagnosis

1. The ABS control unit is equipped with a main CPU and a sub CPU, that check each other for problems.

2. The CPUs check the circuit of the system.

3. Self-diagnosis can be classified into 2 categories.

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

Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.

4. When a problem is detected by self-diagnosis, the system:

Turns the fail-safe relay OFF

Turns the solenoid valve OFF

Turns the pump motor OFF

Turns the ABS indicator ON

Self-diagnosis Table

Diagnostic Trouble

Code(DTC)

11, 13, 15, 17

12,14,16,18

21-24

31-38

41-44

51

52

53

54

61

62

71

81
Detection Item

Wheel sensor (open/short to body ground/short to power)

Wheel sensor (electrical noise/intermittent Interruption)

Pulser

Solenoid (short to body ground/short to wire)

Wheel lock

Motor lock

Motor stuck OFF

Motor stuck ON

Fall-safe relay

Low ignition voltage

High ignition voltage

Different diameter tire

Central Processing Unit (CPU) diagnosis, and ROM/RAM diagnosis
Detection

Timing
Initial
Diagnosis

O

O

O

O
Regular
Diagnosis
O

O

O

O

O

O

O

O

O

O

O

O
Fail-safe Mode

A

S, A and L, S and L

A and L

S

A and L

S and L

A and L

A and L

S

B

B

S

S

Operation Mode Table

Operation

Mode

Regular

operation

Fail-safe

mode-S

Fail-safe

mode-A

Fail-safe

mode-L

Fail-safe

mode-B
Description

Operation in normal condition

The ABS control unit turns the system off when the control unit detects a problem.

If the ABS control unit detects a malfunction during an emergency stop, it will turn off the malfunc-

tioning component, and continue to modulate the rest of the ABS system until the vehicle comes to

a stop. At that, the entire system will be turned off until the problem goes away.

The ABS control unit stores a DTC in back-up memory when it detects a problem. If a problem is

detected when the ignition switch is turned ON (II), the ABS control unit will turn the system off. If

the problem goes away, the ABS control unit will turn the system on again.

The ABS control unit will turn the system off if ignition voltage drops, and will turn on again when

ignition voltage returns to normal.
ABS
Indicator

OFF

Comes ON when a

problem is detected.

Comes ON when a

problem is detected.

ON

Comes ON when a

problem is detected.

On-board Diagnosis Function

The ABS control unit is connected to the 16P Data Link Connector.

The ABS can be diagnosed with the Honda PGM Tester.

The ALB Checker cannot be used with this system. For air bleeding, and checking wheel sensor signals, use the Honda

PGM Tester. See the Honda PGM Tester user's manuals for specific operating instructions.
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Troubleshooting Precautions

ABS Indicator

1. If the system is OK, the ABS indicator goes off 2 seconds after turning the ignition switch ON (II) without starting the

engine, and then comes on again and goes off after 2 seconds. This occurs because the ABS control unit is turned on

by the IG2 power source.

2. The ABS indicator comes on when the ABS control unit detects a problem in the system. However, even though the

system is operating properly, the ABS indicator will come on, under the following conditions.

Only drive wheels rotate

One drive wheel is stuck

Vehicle spin

ABS continues to operate for a long time

Signal disturbance

To determine the actual cause of problem, question the customer about the problem, taking these conditions into con-

sideration.

3. When a problem is detected and the ABS indicator comes on, there are cases when the indicator stays on until the igni-

tion switch is turned OFF, and cases when the indicator goes off automatically when the system returns to normal. For

DTCs 61 and 62, the indicator goes off automatically when the system returns to normal. For all other codes, the indica-

tor stays on until the ignition switch is turned OFF.

4. For DTCs 12, 14, 16, 18, 21, 22, 23, 24, 51, 52 and 53, the indicator goes off when the vehicle is driven again and the sys-

tem is OK after the ignition switch is turned from OFF to ON (II). However, if the DTC is erased, the CPU is reset and the

indicator goes off right after the engine is started if the system is OK.

Diagnostic Trouble Code (DTC)

1. If the CPU cannot be activated and the indicator comes on, the DTC is not memorized.

2. The memory can hold any number of DTCs. However, when the same DTC is detected more than once, the later one is

written over the old one. Therefore, when the same problem is detected repeatedly, it is memorized as 1 DTC.

3. The DTCs are indicated in the order of ascending number, not in the order they occur.

4. The DTCs are memorized in the EEPROM (non-volatile memory). Therefore, the memorized DTCs cannot be canceled

by disconnecting the battery. Perform the specified procedures to erase the DTCs.

Self-diagnosis

1. Self-diagnosis can be classified into 2 categories.

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

• Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.

2. When a problem is detected by self-diagnosis, the system.

Turns the fail-safe relay OFF

Turns the solenoid valve OFF

Turns the pump motor OFF

Turns the ABS indicator ONProCarManuals.com

Troubleshooting
DTC 11 , 13 , 15 , 17 : Whee l Senso r (Open/Shor t t o Bod y Ground/Shor t t o Power )
With th e ignitio n switc h O N
(II) , th e AB S indicato r doe s
not g o off .With th e SC S servic e connec -
to r connecte d (se e pag e
19-119 ), DTC s 11 , 13 , 15 , 1 7 ar e
indicated .
Chec k fo r a shor t t o powe r i n th e
whee l senso r circuit :
1 . Disconnec t th e AB S contro l
unit 22 P connector .2. Star t th e engine .
3 . Measur e th e voltag e betwee n
th e appropriat e whee l senso r
(+) circui t termina l an d bod ygroun d (se e table) .
DTC
11 (Right-front )
13 (Left-front )
15 (Right-rear )
17 (Left-rear )
Appropriat e Termina l
(+) Sid e
No. 9 : FR W (+)
No . 7 : FL W (+ )
No . 19 : RR W (+ )
No . 17:RLW(+ )
(-) Sid e
No. 8 : FR W (-)
No . 6 : FL W (-)
No . 20 : RR W (-)
No . 18 : RL W (-)
Is ther e 2 V or more ?
NOTE : Judgemen t valu e fo r shor t t o
powe r i s 2 V . Repai
r shor t t o powe r i n th e (+ )
circui t wir e betwee n th e AB S
contro l uni t an d th e appropriat e
whee l sensor .
Chec k fo r a shor t t o bod y groun d
i n th e whee l senso r circuit :
Check fo r continuit y betwee n th eappropriat e whee l senso r (+ ) cir -cuit termina l an d bod y groun d(see table) .
I s ther e continuity ?
Chec k fo r a n ope n i n th e whee l
senso r circuit :
Chec k th e resistanc e betwee n th e
appropriat e whee l senso r (+ ) an d
(-) circui t terminal s (se e table) .
Is th e resistanc e OK ?Front/Rear : 45 0 - 2,05 0
(a t 20°C , 68°F) .
Check fo r loos e AB S contro l uni tconnectors , i f necessary , substi -tute a known-goo d AB S contro lunit an d recheck . Repai
r shor t t o bod y groun d in
th e (+ ) o r (- ) circui t wir e betwee n
the AB S contro l uni t an d th eappropriat e whee l sensor .
Replac e th e appropriat e whee l
sensor .
Repair ope n i n the (+) o r (- )
circui t wire , o r shor t t o th e (+ )
circui t wir e i n th e (- ) circui t
wir e betwee n th e AB S contro l
uni t an d th e appropriat e whee l
sensor .
Replac e th e appropriat e whee l
sensor . AB
S CONTRO L UNI T 22 P CONNECTO R
Wir e sid e o f femal e terminal s
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Troubleshooting
DTC 52 : Moto r Stuc k OF F (cont'd )
(From pag e 19-134 )
Chec k fo r a n ope n in th e PM R cir -
cuit :
1 . Disconnec t th e AB S contro l
unit 12 P connector .2. Connec t th e pum p moto r rela y
connecto r termina l No . 2 to
No . 4 wit h a jumpe r wire .3. Measur e th e voltag e betwee n
th e AB S contro l uni t 12 P con -
necto r termina l No . 1 2 an dbod y ground .
I s ther e batter y voltage ?
Chec k fo r a shor t t o powe r i n th e
PM R circuit :
1 . Remov e th e jumpe r wir e fro m
pum p moto r rela y connector .
2 . Star t th e engine .
3 . Measur e th e voltag e betwee n
th e AB S contro l uni t 12 P con -
necto r termina l No . 1 2 an d
bod y ground . Repai
r ope n in th e wir e betwee n
th e under-hoo d fuse/rela y bo x
and th e AB S contro l unit .
Wire sid e o f femal e terminal s
I s ther e batter y voltage ? Repai
r shor t t o powe r i n th e wir e
betwee n th e under-hoo d fuse /
rela y bo x an d th e AB S contro l
unit.
If th e proble m occur s again ,
replac e th e AB S contro l unit .
PUM P MOTO R RELA Y CONNECTO R
JUMPERWIRE
Termina l sid e o f femal e terminal s
AB S CONTRO L UNI T 12 P CONNECTO R
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Modulator Unit

Removal/Installation

NOTE:

Do not spill brake fluid on the vehicle; it may damage the paint; if brake fluid does not contact the paint, wash it off

immediately with water.

Take care not to damage or deform the brake lines during removal and installation.

To prevent the brake fluid from flowing, plug and cover the hose ends and joints with a shop towel or equivalent mate-

rial.

Removal

1. Disconnect the modulator unit and pump motor connectors.

2. Disconnect the brake lines, then remove the proportioning control valve.

3. Remove the modulator unit.

Installation

1. Install the modulator unit.

2. Install the proportioning control valve, then connect the brake lines. Tighten the flare nuts to 15 N-m (1.5 kgf-m, 11 Ibf-ft).

3. Connect the modulator unit and pump motor connectors.

4. Bleed the brake system, starting with the front wheels.

5. Start the engine, and check that the ABS indicator goes off.

6. Test-drive the vehicle, and check that the ABS indicator does not come on.

From

From left-front

right-front
MODULATOR UNIT

RUBBER MOUNT

MODULATOR UNIT

CONNECTOR

8 mm BOLT

22 N-m (2.2 kgf-m, 16 Ibf-ft)

BRACKET
PROPORTIONING

CONTROL VALVE

6 mm BOLT

9.8 N-m (1.0 kgf-m, 7.2 Ibf-ft)

PUMP MOTOR CONNECTOR

6 mm NUT

9.8 N-m (1.0 kgf-m, 7.2 Ibf-ft)ProCarManuals.com