Brake HONDA CIVIC 2003 7.G Manual Online

General Troubleshooting Information
ABS Indicator
. lf the system is OK,theABS indicator goes off 2
seconds after turning the ignition switch ON (ll)
without starting the engine, and then comes on again
and goes off 2 seconds later after starting the engine.
This occurs because the ABS control unitisturned
on by the lG2 power source.. 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 indicator
will come on under these conditions:- Only the drive wheels rotate- One drive wheel is stuck- The vehicle goes into a spin- The ABS continues to operate for a long time.- The vehicle is subjected to an electrical signal
disturbance
To determine the actual cause of the problem, question
the customer about the problem. taking the above
condilions into consideration.
. When a Droblem is detected and lhe ABS indicator
comes on, there are cases when the indicator stays
on until the ignition switch is turned OFF, and cases
when the indicator goes off automatically when the
sYstem returns to normal.- DTC 61: The ABS indicator goes off automatically
when the system returns to normal.- DTC 11, 13,15,17 ,31,32,33, 34, 35, 36, 37, 38, 54,
or 81: The ABS indicator stays on until the ignition
switch is turned OFF whether or not the system
returns to normal.- DfC 12, 14, 16, 1a,21,51,52, or 53; The ABS
indicator goes off when the vehicle is driven again
and the system is OK after the ignition switch is
turned from OFF to ON {ll}.
Diagnostic Trouble Code {DTCI
. The memory can hold three DTCS. However, when
the same DTC is detected more than once, the more
recent DTC is written over the earlier one.
Therefore, when the same problem is detected
repeatedly, it is memorized as a single DTC.. The DTCs are in the order they occurred, beginning
with the most recent.. The DTCS are memorized in the EEPROM (non-
volatile memory). Therefore. the memorized DTCs
are not cleared when the battery is disconnected, the
ignition switch is turned off, or the system returns to
normal. Do the specified procedures to clear the
DTCs.
Self-diagnosis
. Self-diagnosis can be classified into two categories:- Initial diagnosis:
Done right after the engine starts and until the ABS
indicator goes off- Regular diagnosis:
Done rightafterthe initial diagnosis until the
ignition switch is turned OFF. When a problem is detected by self-diagnosis, the
system does the following:- Turns the ABS indicator on- Memorizes the DTC- Stops ABS control
Kickback
The pump motor operates when the ABS is functioning,
and the fluid in the reservoir is forced out to the master
cylinder, causing kickback at the brake pedal.
Pump Motor
. The pump motor operates when the ABS is
functioning.. The ABS control unit checks the pump motor
operation when the vehicle is started the first time
after the ignition switch is turned ON (ll). You may
hear the motor operate at this time, but it is normal.
(cont'd)
19-31

4. The blinking frequency indicates the DTC. DTCS are
indicated by a series of long and short blinks. One
long blink equals 10 shon blinks. Add the long and
short blinks together to determine the DTC. After
determining the DTC, refer to the DTC
Troubleshooting Index.
NOTE:. lf the DTC is not memorized, the ABS indicator
will go off for 3.6 seconds, and then come back
on.. lf the ABS indicatorstays on, troubleshootfor"ABS indicator does not go off" (see step 1 onpage 19-53).
Th€ system will not indicate the DTC unless these
conditions are met:. The brake pedal is not pressed.. The ignition switch is turned ON {ll).. The SCS circuit is shorted to body ground before
the ignition switch is turned ON (ll).
Example ot DTC 15
Long blinkShort blinks{five timesl
Examole of DTC 22
Long blinks (two times)
Turn the ignition swltch OFF,
Disconnect the Honda PG M Tester from the DLC.
5.
How to Clear ABS DTCs
Honda PGM Tester Method:
1. With the ignition switch OFF, connect the Honda
PGM Tester (A)to the l6Pdata link connector (DLC)
{B} under the driver's side of the dashboard.
Turn the ignition switch ON (ll), and clearthe
DTC(s) by following the screen prompts on the
PGM Tester.
NOTE: See the Honda PG l\4 Tester user's manual
for sDeclf ic instructions.
Cycling the lgnition Switch Method:
Clear the DTC by turning the ignition switch ON (ll) then
OFF at least 20 times.
19-33

Symptom Troubleshootin g Index
SymptomDiagnostic procedureAlso check forABS indicator does nol come onABS Indicator Circuit Troubleshooting (see page
19-52)
ABS indicator does not go off and no
ABS DTC is stored
ABS Indicator Circuit Troubleshooting {see step 1
on Daqe 19-53)
Brake system indicator does nol come
on
Brake System lndicator Circuit Troubleshooting(see paqe 19-55)
Brake system indicator does not go off
and no ABS DTC is stored
Brake System Indicator Circuit Troubleshooting(see steo 1 on Daqe 19-55)
19-35

Terminal
number
Wire
color
TerminalsignDescriptionMeasurement
TerminalsConditions {lgnition
switch oN lll))
Voltage
14WHT/
BLK
STOPDetects brake
switch siqnal
I4-G NDBrake pedalPressedEattery
voltaoeReleased
t5BLV
ORN
rG2Power source for
activating the
svstem
15-GNDBaftery
voltage
16BLKM-GNDGround for the
0umD motor
16-GN DBelow 0.3 V
WHT/
RED
+ B-MRPower source for
the oumD motor
17-GNDAt alltimesBattery
voltaoe
18WHT/
GRN
+ B-FSRPower source for
the valve relav
,18-GNDAt alltimesBattery
voltaoe'19BLKGNDGround for the
modulator
assemDtv
19.GNDBelow 0.3 V
20B LU/
RED
ABSDrives ABS
indicator
20-GNDABS
indicator
ONAbout 11 V
OFFBelow 1 V
BRN/
YEL
EBD(Electronic brake
distribution)
Drives brake
system indicator
21-GNDBrake system
indicator
OFFBelow 0.3 V
ON for
bulb
cnecK
8attery
voltage
(cont'd )
19-37

ABS Gomponents
System Description (cont'd)
Features
When the brake pedal is pressed during driving, the wheels can lock before the vehicle comes to a stop. In such an
event. the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of the vehicle is
reduced if the rear wheels are locked, creating an extremely unstable condition. The ABS precisely controls the slip
rate of the wheels to ensure maximum grip force from the tires, thereby ensuring the maneuverability and stability of
the vehicle.
The ABS calculates the slip rate of the wheels based on the vehicle speed and the wheel speed, then it controls the
brake fluid pressure to reach the target slip rate.
Grip Force of Tire and Road Surface
TARGET SLIP RATE
COEFFICIENT OFFRICTION
SLIP RATE
19-38

ABS Components
System Description (cont'd)
ABS Modulator
The ABS modulator consists of the inlet solenoid valves, outlet solenoid valves, reservoir, pump, pump motor, and the
damping chamber. The modulator reduces the caliper fluid pressure directly. lt is a circulating-type modulator
becausethe brakefluidcirculatesthroughthecaliper,reservoir,andthemastercylinder.Thehydrauliccontrol has
three modes: pressure intensifying, pressure retaining, and pressure reducing. The hydraulic circuit is an independent
four-channeltype, one channel for each wheel.
Pressure intensifying mode: Inletvalve open, outlel valve closed
Master cylinder fluid is pumped out to the caliper.
Pressure retaining mode: lnlet valve closed, outlet valve closed
Caliper fluid is retained by the inlet valve and outlet valve.
Pressure reducing mode: Inlet valve closed, outlet valve open
Caliper fluid flows through the outlet valve to the reservoir.
lvlotor operation mode: When starting the pressure reducing mode, the pump motor is ON.
When stopping ABS operation, the pump motor is OFF.
The caliper fluid is pumped out by the pump, through the damping chamber, to the
master cvlinder.
19-40

ABS Components
q,
CONNECTOR A {12P)BRAKE PEDAL POSITIONSWITCH 4P CONNECTOR
Circuit Diagram (cont'd)
UNDER-HOOD FUSE/RELAY BOX CONNECTORSCONNECTOR A {12P) CONNECTOR B {2P}
UNDER.DASH FUSE/RELAY BOX CONNECTORSCONNECTOR I {5P)CONNECTOR K I17P)MULTIPLEX CONTROLUNIT 13P CONNECTOR
CONNECTOR B I22PI
1l2l3l,/15
GAUGE ASSEMBLY CONNECTORS
CONNECTOR A I22P)
WHEEL SENSOR 2P CONNECTORS
FRONT
J --T:-l Ltqtt/)l'l L_.:-:J r\-r-----Tr'e:l
RIGHT.REAR LEFT-REAR
tslTt?t /J 1T-1\I tL | rlziJ
Terminal side of male lerminals
ABS CONTROL UNIT 3IP CONNECTOR
OATA LINK CONNECTOR {16P)
Terminal side of female terminals
Wire side of female terminals
1234567
810111213141511
123,/ ,/
67891011n213
1245678I11121415
161118192021/1,/1,/vl,/l
/t,/t/t,/t/
19-44

ABS Components
DTC Troubleshooting (cont'd)
DTC 81: CPU (Central Processing Unit)
1. Clear the DTC, then disconnect the Honda PGM
Tester.
2. Test-drive the vehicle.
Does the ABS indicator come on and is DTC 81
indicated ?
YES Replace the ABS modulator-control unit.l
NO-The system is OK at this time. t
19-52
ABS Indicator Gircuit
Troubleshooting
ABS indicator does not come on
1. Turn the ignition switch ON (ll), and watch the ABS
indicator.
Does the ABS indicator come on?
YES The system is OK at this time.I
NO Go to step 2,
Pull up the parking brake lever.
Does the btake system indicator come on?
YES Go to step 3.
NO Repair open in the indicator power source
circuit. lf necassary, substitute a known-good ABS
modulator-control unit, and recheck. I. Blown No, 10 (7.5A) fuse.. Open in the wire between the No. 10 (7.5A)fuse
and lhe gauge assembly,. Open circuit inside the fuse box.
Turn the ignition switch OFF.
Disconnect the ABS control unit 31P connector.
Turn the ignition switch ON (ll).
Does the ABS indicator come on?
YES-Check for loose terminals in the ABS control
unit 31P connector. lf necessary, substitute a
known-good ABS modulator-control unit, and
recheck.l
NO Go to step 6.
Turn the ignition switch OFF.
Remove the gauge assembly (see page 22-64).
3.
5.
6.
7.

Brake System Indicator Gircuit Troubleshooting
Brake system indicator does not come on
'1. Discon nect the m ultiplex contro I unit l3Pconnector
and the ABS control unit 31P connector.
2. Check for continuity between the ABS control unit
3l P connector terminal No,21 and bodyground.
ABS CONTROL UNIT 31P CONNECTOR
Wire side of female terminals
ls there continuity?
YES Repair short to body ground in the wire
between the multiplex control unit and the ABS
control unit.l
NO Go to multiplex control system
trou bleshooting lsee page 22''172).a
Brake system indicator does not go off
1. Turn the ignition switch ON {ll).
2. Release the parking brake.
Does the brake system indicatot go ofl after
several seconds?
YES The system is OK at this time.l
NO Go to step 3.
3. Check the brake fluid level.
ls the level OK?
YES Go to step 4.
NO Refill the brake fluid, and recheck.l
4. Check the ABS indicator.
Does the ABS indicator stay on?
YES Read the ABS DTC (see step 1 on page 19-32).
and do the applicable troubleshooting for the DTC
NO Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the ABS control unit3lPconnector.
7. Connect the ABS control unit 31P connector
terminal No. 21 and body ground with a jumper
ABS CONTROL UNIT 31P CONNECTOR
(cont'd )
Wire srde of lemale lerminals
19-55

ABS Components
8.
9.
10.
11.
12.
13.
Brake System Indicator Gircuit Troubleshooting (cont'd)
Turn the ignititon switch ON (ll).
Check the brake system indicator.
Does the brake system indicatot go off?
YES-Replace the ABS modulator-control unit.l
NO-Go to step 10.
Turn the ignition switch OFF.
Connect the multiplex control unit 13P connector
terminal No. 'l and body ground with a jumper wire.
MULTIPLEX CONTROL UNIT 13P CONNECTOR
JUMPERWIRE
Wire side of female terminals
Turn the ignition switch ON (ll).
Check the brake system indicator.
Does the btake system indicatot go off?
YES Repair open in the wire between the
multiplex control unit and the ABS control unit.l
NO Go to multiplex control system
troubleshootin g (see page 22-17 2). a
19-56
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