2003 HONDA CIVIC brake fluid

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

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 Modulator-Control Unit Removal and lnstallation
NOTE:. Donotspill brake fluid on the vehicle; it may damage the painU if brakefluidgetsonthepaint,washitoff
immediately with water.. Becareful 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 orequivalent
malenal.
Removal
'1. Turn the ignition switch OFF.
2. Pull upthelock(A) oftheABScontrol unit3lPconnector(B),thendisconnecttheconnector.
FLARE NUTl5 N.m (1.5 kgt.m,11 lbt.ftl
6)o
CII mm NUT8.8 N.m {0.9 kgl m.6.5lbf ft)
6 mm BOLT9.8 N.m11.0 ksf.m,7.2lbf.ft)
\.
--/Q \,
\---'
(cont'd)
19-57

Connectors and Harnesses
Engine Compartment Wire Harness (Left branch)
AirJuel (A,,/F) ratio sensorBrake fluid level switchCondenser fan motorCruise control actuatorELD unitFog light connectorLeft front ABS wheel sensorLeft front airbag sensorLeft front parking lightLeft front side marker lightLeft lrontturn signal lightLeft headlightLeft hornRadiator fan motorRadiator fan switchSecondary heated oxygen (SHO2S)
Test tachometer connectorWindshield wiper motorUnder'hood fuse/relay boxconnector A {see page 22-44)Under-hood f use/relay boxconnector B (see page 22-44)Under hood fuse/relay boxconnector C (see page 22-44)Under hood fuse/relay boxconnector D (see page 22 44)Under-hood fuse/relay box
Front of engine companmentLeft side of engine compartmentLeft side of engine compartmentLeft side o{ engine compartmentFront of engine compartmentUnder right side of cowl coverUnder'hood f use/relay boxLeft side of engine compartmentLeft side of engine companmentBehind left side of front bumperBehind left headlightBehind left side of front bumperEehind left headlightBehind left headlightBehind front bumperLeft side of engine compartmentFront of engine compartmentLeft side of engine compartment
Left side of engine companmentL.Jnder left side of cowl coverL.Jnder hood fuse/relay box
L.Jnder hood fuse/relay box
L.Jnder'hood f use/relay box
underhood fuse/relay box
Under-hood fuse/relay box
24222
2519
12
17
13202123
3
117
I
10
5
6
l2
2243,l
222223l224
252
5
12
Connector to Harness Index (cont'dl
\
22-20

Ground Distribution
Ground to Components Index
GroundComponent or circuit qrounded
Batterv, Transmission housinq
E ngine
G 101ECM (PG is BLK; LG is BRN/YEL)
BLK: IAC valve, lgnition coils, Vehicle speed sensor, VTEC solenoid valve
BRNA/EL: Camshaft oosition (CMP) sensor. CKP sensor, TDC sensor. VTEC oil pressure switch
G 15']EPS control unit
G201ELD unit. Multiplex control inspection connector, Multiplex control unit, Power window relay, Rear
window washer motor, Right front parking light, Right front side marker light, Right front turn signal
light, Turn signal/hazard relay, Washer fluid level sensor (Canada) , Windshield washer motor,
Windshield wiDer motor
G202ABS modulator-control unit
G301
G401
Blower motor relay, Brake fluid level switch, Condensor fan motor, Cruise control actuator, Left front
parking light, Left front side marker light, Left front turn signal light, Radiator fan motor, Radiator fan
swrtcn
Combination liqht switch, lqnitlon kev srvitch, Wiper/wasfrer sr,virch
G402Left and riqht airbaq sensors, SRS unit
G 451Data link connector (DLC)
G501Clutch interlock switchm Clutch pedal position switch (for cruise control), Cruise control main switch,
Cruise control unit, Daytime running lights control unit (Canada), Driver's door lock knob switch,
Driver's door lock switch, Driver's power window motor, Heater control panel, Left power mirror
defogger (Canada), left side turn signal light, Moonroof control unit, Monroof open and close relays,
Moonroof position sensor '1, Moonroof seitch, Power mirror switch, Power transistor, Power window
master switch. SDotliqhts
G502Accessory power socket, Gauge assembly, Keyless receiver unit, lvlultiplex control unit, Right power
mirror defogger {Canada)
G503Audio unit
G551Driver's seat belt switch, Fuel gauge sending unit, Fuel pump, Memory erase signal (IMES) connector,
OPDS unit. Rioht seat belt switch
G552High mount brake light, License plate lights, Rear window defogger, Rear window defogger noise
condenser. Rear window wioer motor, Hatch latch switch
Back-up lights, Brake lights, Rear side marker lights, Rear turn signal lights, Rear window wiper noise
condenser, Rear window wiper intermittent control unit, Taillights
22-48

Gauges
\-Component Location Index
PARKING BRAKE SWITCHpage 19-10
FUEL GAUGE SENDINGpage 11-156ENGINE OIL PRESSURE SWITCHpage 8-4
GAUGE ASSEMBLYSelJ-diaqnostic Procedure, page 22-56Gauqe dulb Replacement, page 22 63Rep6cement, page 22-64Coolant Temperature GaugeTroLrbleshooting, page 22'64
BRAKE FLUID LEVEL SWITCHpage 19-10VEHICLE SPEED SENSOR {VSS)Troubleshooting, page 22-65Beplacement, page 22-67
22-54
\

Gauges
Self-diagnostic Procedure
The gauge assembly has a self-diagnosis function.. The Beeper Drive Circuit Check. The Indicator Drive Circuit ChecL. The LCD Segments Check. The Gauges Drive Circuit Check (Speedometer, Tachometer, Fuel gauge, Coolant temperature gauge). The Communication Line Check (the coolanttemperature signal line between the gauge and ECM)
NOTE: Indicators are also controlled via the communication line.
Entering the self-diagnosis f unction:
Before doing the self-diagnosis function, check the No. 9 (10A) fuse in the under-hood fuse/relay box and No. 10 {7.5A)fuse in the under'dash fuse/relay box.
1. Push and hold the trip/reset button.
2. Turn the lighting switch ON.
3. Turn the ignition switch ON (ll).
4. Within 5 sec., turn the lighting switch OFF, then ON and OFF again.5. Within 5 sec., release the trip/reset button, then push and release the button four times reDeatedlv.
NOTE:. While in the self-diagnosis mode, the dash lights brightness controller operates normally.'Whileintheself-diagnosismode,thetrip/resetbuttonisusedtostartthebeeperdrivecircuitcheckandthegauge
drive cicuit check.. lf the vehicle speed exceeds 1.2 mph 12 km/h) orthe ignition switch is tu rned OFF, the self,diag nosis mode ends.
oN flrl
lgnition
Switch
Lighting
Switch
Trip/Reset
Switch-> Move to selt-diagnosis mode.
5 sec.5 sec.
The Beeper Drive Circuit Check:
When entering the self-diagnosis mode, the beeper sounds five times
The Indicator Drive Circuit Check:
When entering the self-diagnosis mode, the following indicators blink.
Seat belt indicator, Door/hatch indicator, Brake system, Lowfuel indicator, Maintenance required indicator (USA),
Washer fluid level indicator (Canada), Oil pressure light.
v
OFF
22-56

IJ
IJ
IJ
CavitvWireTest conditionTest: Desired resultPossible cause if resuk is not obtainedX8WHT/BLKUnder allconditionsAttach to ground:The ignition keylight should come on.Blown No.3 (7.5A)fuse in the under,hood
Blown LEDAn ooen in the wireo7GRN/REDCeiling light switch inthe middle position,all doors closed
Attach to ground:The ceiling light,spotlights should come on.Elown No. 3 (7.54)fuse in the undeFhood
Faulty ceiling lightAn oDen in the wirec]1BLU Under all conditionsAttach to ground: Dash lights shouldBlown No. 2 (15Aifuse in the under-hoodfuse/relay boxFaulty taillight relayAn ooen in the wireF8GRN/REDBrake fluid reservoirfloat in downposition (brake fluid
Check for voltage to ground:There should be less than I V.Faulty brake fluid level switchAn open in the wire
Brake lluid reservoirfloat in up position(brake fluid at fulllevel)
Check for voltage to ground:There should be 5 V or more.Faulty brake fluid level switchShortto ground
E10YELUnder all conditionsCheck for voltage to ground:There should be battery voltage inthe sleep mode and 3 Tvoltswhen
. An open or short in the wire
K10WHT/GRNUnder all conditionsCheck for voltage to ground:There should be battery voltage inthe sleep mode and 3 Tvoltswhen
An open or short in the wire
22-177