1999 HONDA CIVIC Wheel

Brake Hoses/Lines
LJ
Inspection/Torque Specifications
t. Inspect the brake hoses for damage, deterioration, leaks, interference, and twisting.
2. Check the brake lines for damage, rusting. and leakage. Also check for bent brake lines.
3. Check for ieaks at hose and line ioints and connections, and retighten if necessary'
4. Check the master cylinder and ABS modulator unit for damage and leakage
CAUTION: Replace tho brake hose clip whenev€r the brake hose is serviced.
ABS MODULATOR UNIT-Io-BRAKE l-lNE19 N.m (1.9 kgf.m, 14lbl.ftl
PROPOBTIONING CONTROL VALVE.io-BRAKE LINEl5 N.m (1.511 tbf.ftl
MASTER CYLINDER-Io-BMKE LINE
15 N.m (1.5 ksrf.m, 11 lbf'ft)
REAR DISG BRAKE:BRAKE HOSE-to4ALlPER
{BANJO BOLT}34 N.m (3.5 kgtm,25 lbf ftlBLEEO SCREW9 N'm (0.9 kgf.m, 6.5 lM.ftlBRAKE LINE-to-WHEEL CYLINDER15 N.m (1.5 kgl.m, 11 lbf.ftlBLEED SCREW7 N.m {0.7 kst m, 5 lbf,ttl
JBRAKE LINE-io-aRAKE HOSE15 N.m {1.511 tbtft)
BRAKE LINE-Io-BRAKE HOSE15 N.m (1.5 kgt.m, 11 lbf'ft)
(BANJO BOLT}3,1 N.m 13.5 kgf.m, 25 lbf.ft)
J
19-39

L-
t
Anti-lock Brake System (ABSI
Special Tools ............. 19-44
Component Locations ......................... 19-45
Anti-lock Brake System (ABS)
Features/Construction ..................., 19-46
Operation ............... 19-47
Circuit Diagram ......... 19-50
ABS Control Unit Terminal
Arrangement ......... 19-52
Troubleshooting Precautions ............. 19-54
Diagnostic Trouble Code (DTCI
Diagnostic Trouble Gode (DTCI
Indication ........... 19-56
DTC Erasure ........... 19-57
Symptom-to System Chart ............. 19-58
Troubleshooting
ABS Indicator Light Does Not
Come On ............ 19-60
ABS Indicator Light Does Not
Go Off ............................................ 19-62
Wheel Sensor ........ 19-64
Solenoid ................. 19-60
ABS Pump Motor ............................. 19-68
Main Relay ............. 19-71
lgnition Voltage .... 19-73
Central Processing Unit {CPU} ........ 19-74
Modulator Unit
Removal/lnstallation ....................... 19-75
ABS Control Unit
Replacement ......... 19-76
Pulsers/Wheel Sensors
Inspection .............. 19-76
Wheel Sensor Replacement ............ 19-77
t/

Component Locations
ta
SERVICE CHECK CONNECTOR {2PIBIGHT.REAR WHEELSENSOR CONNECTORMOOULATOR UNITABS CONTROL UNIT
RIGHT-REAR WHEEL SENSOR
LEFT.R€AR WHEELSENSOR CONNECTOR
J
UNDER.DASH FUSE/RELAY 8OX
LEFT.FRONT WHEEL SENSOR
ABS +B (20 A) FUSE
UNDER.HOOD FUSE/RELAY BOX
lcl lilo Al FUSE
ABS INDICATOR LIGHT
UNOEF.DASI{ FUSE/RELAY BOX
HORN/STOP I15 A) FUSE
UNDER.HOOO ABS FUSE/RELAY BOX
PUMP MOTOR {'O A} FUSE
PUMP MOTOR BELAY
E
o
METEB I7.5 AI FUSE
0
0
0
00000 n
00000 u
BR DEF RLY 17,5 A) FUSE
t
MTR CHECK (7.5 AI FUSE
19-45

Anti-lock Brake System (ABSI
Featu res/Construction
When the brake pedal is depressed during driving, the wheels can lock before the vehicle comes to a stop, In such a case,the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of the vehicle is reduced if therear wheels are locked, creating an extremely unstable condition. The ABS precisely controls the slip rate of the wheels toensure the grip force of the tires. and it thereby ensures the maneuverbility and stability of the vehicle.Judging the vehicle speed. 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 attain the target slip rate.
Grip Force of Tire and Road Surlace
COEFFICIENT OFFRICTION
TARGET SLIP RATE
Slip Rate
BRAKINGSTART POINT
ROTATIONALDIRECTION
RADIALDIRECTIONOF THEROTATIONALOIRECTION
A: Distance without slio8: Slippsd distanceC: Actuel distance
sr-rrmre=f=SLIP RATEVEIIICLE SPEED - WHEEL SPEEOVEHICLE SPEED
19-46

t-Operation
t
ABS Control Unit
Main Control
The ABS control unit detects the wheel speed based on the wheel sensor signal it received, then it calculates the vehicle
speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration based on the
rate of deceleration.
The ABS control unit calculates the slip rate of each wheel. and it transmits the control signal to the modulator unit
solenoid valve when the slip rate is high.
The pressure reduction control is a three-mode system, that is pressure reduction, pressure retaining and pressure intensi-
fying modes.
Self -diagnosis Funqtion
The ABS control unit is equipped with a main CPU and a sub CPU, and the CPUS check each other'
The CPUs check the circuit of the svstem.
When the CPUS detect failure, they shift to the "system down mode" or the "control inhibition mode"
The self-diagnosis can be classifield into these four categories:
O: Initial diagnosis
@: Except ABS control
@: During ABS control
@: During warning
On-board Diagnosis Funstion
The ABS control unit is connected to the data link connector {16P).
The ABS system can be diagnosed with the Honda PGM Tester.
(cont'd)
MODEABS INDICATOR LIGHTMAIN
RELAY
SOLENOID
VALVECPURestart conditionDTC
SYSTE IV
DOWNONNo
operation
Drive
inhibitionOperation*rlgnition
switchOFF + ONMemory
CONTROL
INHIBITIONONNo
operalron
Drive
inhibitionOperationAutomaticMemory
*1: Except CPU failure
/
19-47

Anti-lock Brake System {ABS)
Operation (cont'dl
ABS Modulator
The ABS modulator consists of the inlet solenoid valve, outlet solenoid valve, reservoir, pump, pump motor and thedamping chamber.
The modulator reduces the caliper fluid pressure directly, and it is also referred to as a circulating type because the brake fluidcirculates through the caliper, reservoir and the master cylinder.The hydraulic control has three modes: pressure reducing, pressure retaining, and pressure intensifying.The hydraulic circuit is the independent four channel type, one channel for each wheel.
RF LR
Pressure intensifying mode: Inlet valve open, outlet valve closed
Pressure retaining mode:
Pressure reducing mode:
Motor operation mode:
rN: INLETVALVE {NORMALtY OpENIOUT: OUTIET VALVE {NORMALIY CTOSED)Master cylinder fluid is pumped out to the caliDer.Inlet valve closed, outlet valve closedCaliper fluid is retained by the inlet valve and outlet valve.Inlet valve closed, outlet valve oDenCaliper fluid flows through the outlet valve to the reservoir.When starting the pressure reducing mode, the pump motor is ON.When stopping ABS operation, the pump motor is OFF.The reservoir fluid is pumped out by the pump, through the damping chamber, to the mastercvlinder.
PUMP MOTOR
19-48

L
Wheel Soeed and Modulator Contlo
t
OUTLETVALVE ON
OFF
INLETVALVE ON
OFF
t\,40ToR
ON
OFF
when the wheel speed drops sharply below the vehicle speed, the inlet valve closes to retain the caliper fluid pressure
When the wheel speed drops further, the outlet valve opens momentarily to reduce the caliper fluid pressure. The pump
motor starts at this time.
As the wheel speed is restored, the inlet valve opens momentarily to increase the caliper fluid pressure.
Wheel SensoJ
The wheel sensors are the magnetic contactless type
As the gear pulser teeth rotate past the wheel sensor's magnetic coil, AC current is generated The AC frequency changes
in accordance with the wheel speed. The ABS control unit detects the wheel sensor signal frequency and thereby detects
the wheel speed.
There are four wheel sensors, one for each wheel
The gear pulser has 50 teeth.
EEL SPEED
at LOW SPEEDgl
=o
GEAR PULSEBWHEEL SENSOBat HIGH SPEED
/
19-49

tABS CONIROL UN]TECM / PCMISCS'
V
,,, +-{l-, ?,,] B6li! [,b.,,,,,-F-
SENSOR
+B
YWHTNED
8U(
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G,Ol, Ga02
l
\EWIK
LEFT.
RIGHT,
LEFT
;___.|-1
**1. ,I
coierou
SERVICE CHECKCONNECTOR (2P}
lrl2f
OATA LINKCONNECTOR O 6P)
WHEEL SENSOR2P CONNECTOB
FRONT
/.[Ttl\
REAR
tc-T-lI zlr[B'1213
ABS CONTROL UNIT 26P CONNECTOR1O numb€r)
12346/8Il0./ tt12r3
14 t516 1719 ,/2123
-o&"^1'
cot, croz
Terminalside ofmale terminals
ABS CONTROL UNIT 22P CONNECTOR1! numb€r)
/Wire side of female terminals
19-51