1996 HONDA CIVIC Oi pump

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

ABS Control Unit Terminal Arrangement
ABS CONTROL UNIT 26P CONNECTOR
Wire side of temale terminals
Terminalnumo0rWirecolorTerminal signTerminalnamoDgscriptionVoltage
Conditions(lgnition Switch ON flt))Output voltagoteminals
PCOM(Primary
common)
Power source for the solenoidvalve and pump motor.1-GNDON
=ONOV
AC: 3-6 V
BLK/WHTscoM(Secondary
common)
Power source for the solenoid
2.GNDOFF
lConnect the SCS service\
conneclor lApprox. 3 V
ELVBLUtG2(lgnition 2)Detects ignition switch 2
!9nal. (system activate signal)3-GNDBatt€ry voltage
BLU/YELRRO(Rear-right 0)Detects right-rear wheelsensor signal.4-17
When the wheel isturned at 1 turn/second.
53 mV or above ondigitaltester (ACra nge) {Fefera nce)150 mvp-p or aboveon oscilloscope
6GRYRLO(Rear-left 0)Detects left-rear wheel sensorsrgnal.6-19
8GRNFRO(Front-right 0)D€tects right-front wheelsgnsor srgnal,a-21StopsApprox.2.5VSTOP(Stop)hects brake switch signal.(Prevents unnecess€ry ABS operation)9-GNDBrake pedal depressed.Battery voltage
Brake pedal released.OV
10BRN^/vHTFLO(Front-left 0)
Detects left-front wheel sensorsignal.
10-23
When the wheel isturned at 1 turn/secono.
53 mV or above ondigitaltester (ACrange) (Referance)
150 mVFporaboveon oscilloscope
9!opsApprox. 2.5 V
12YELRLOUT(Rearjeft outlet)
Drives left-rear outlet solenoid
12.GNDON-9ONOV
OFFAC: 3^6 V
REDMHTRR]N(Rear-right
inlet)
Drives right-rear inlet solenoidvalve.13-GNDOFF
lconnect the SCS service]i connector IApprox. 3 V
14B1(Battery 1)Power source for the solenoidvatve and pump motor.14.GND
Battery voltage15WHT/G R N82(Baftery 2)Power source for the solenoidvarve ano pump motor.15.GND
r6BLKGND2{Ground 2)Ground for the ABS controlunit.16-GNDBelow 0.3 V
17GRN/'/ELRR1(Rear-right 1)Detects right-rear wheelsensor signal.17-4
When the wheel is turnedat 1 turn/second.
53 mV or aboveon digitaltester(AC range)(Referance) 150mVp-p or aboveon oscilloscope
19LT BLURLl(Rea.-left 1)Detects left-rear wheel sensorsagnal.19-6
GRN/BLKFRl(Front-right 1)Detects right-front wheelsensor signal.21-8
FL1(Front-left 1)Detects left-front wheel sensorsignal.23-10StopsApprox. 2.5 V
REDRL-IN(Rear-lett inletl
Drives left-r€ar inlet solenoid
25.GND
ut
ON
'6
-9ONOV
OFFAC: 3-6 V
OFF
lconnect the SCS service] connector lApprox. 3 V
BLKGND3(Ground 3)Ground for the ABS cgntrolunit.26.GNDBelow 0.3 V
19-52

e\
t
ABS CONTROL UNIT 22P CONNECTOR
Wire side of female terminals
TerminalnumbelWirocororTerminalsignDe3cription
Volt.ge
ConditionE(lgnition Switch ON (ll)lOutput voltagolTqrminal namslterminils
RED/BLUFR-IN{Front-rightinlet)
Drives right-front inletsolenoid valve.
I-GNDriJ
ON-9ONOV
OFFAC: 3-6 V
OFF
/Connect the SCS servicq
connector IApprox. 3 V
BRNscs(Service checksignal)
Detects service check signal
{Diagnostic trouble codeindication)4-GND
SCS service connectorconnected.OV
SCS service connectordisconneded.Appro)(. 5 V
7BLU/RED(Warning
ramp)
Drives ABS indicator light (The
indicator light go€s off when
ABS control unit outputs bat-
tery volta9e),
7-GND
Indicator light ONApprox, 2 V
Indicator light OFFBattery voltage
8BLU/YELNot used.
10YEUBLKFL.OUT{Front-leftoutlet)
Drives left-front outletsolenoid valve.10-GNOON
ONOV
OFFAC:3-6 V
11RED/BLKFLIN{Front-l€ft inlet)
Drives left-front inlet solenoid11-GNDOFF
lconnect the SCS servicq
connector IApprox. 3 V
YEUBLU
FR.OUT(Front-right
outlet)
Drives right-front outlet
solenoid valve.12-GNO
l4LT BLUDLC(Data linkconnector)
Communicates withPGM Tester.Honda14.GNDApprox. 5 V
17BRNA/ELMCK
lMotor check)
Detects pump motor drivesrgnal.17.GNDPumpmotorreray
ONBattery voltage
OFFOV
19YELREDPMR(Pump motorreray,
Drives pump motor relay.
19-GND
ONONOV
OFFAC: 3-6 V
OFFponnect the SCS sewicq
connedor lApprox. 3 V
BLURR-OUT(Rear-right
outletl
Drives right-rear outlel
solenoid valve.
21-GNDuJ
ON
Pumpmotorrelay
ONOV
OFFAC: 3-6 V
OFF
lconnect the SCS servicq
connedor )Approx. 3 V
22BLKGND2(Ground 2)Ground for the ABS controluntt.22-GNDBelow 0.3 v
19-53

tJ
t\
Kickback
1. The 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.
2. TheABScontrol unit operates the solenoid valve when the brake pedal is released afterthe initial diagnosis Youmay
hear the faint solenoid valve operation sound at this time. but it is normal.
Pump Motor
1. The pump motor operates when the ABS is functioning
2. The ABS control unit checks the pump motor operation during acceleration. You may hear the faint operation sound
at this time. but it is normal.
Brake Fluid Replacament/Air Blsading
1. Brake fluid replacement and air bleeding procedures are the same as for conventional brakes
Troubleshooting
1. The troubleshooting flowcharts explain the procedures on the assumption that the cause of the problem is still pre-
sent and the ABS indicator light is still on.
Note that troubleshooting following the flowchart when the ABS indicator light does not come on can result in incor-
rect judgment.
2. Ouestion the customer about the conditions when the problem occurred, and try to reproduce the same conditions
for troubleshooting.
self,diagnosis is made at various times such as the initial diagnosis, except ABS control. during ABS control, during
acceleraiion, during the specified vehicle speed, etc. Therefore, the symptom cannot be checked unless the check
conditions match with the problem conditions
3. When the ABS indicator light does not come on during the test drive, but the troubleshooting is performed based on
the DTC, check for the loose connectors. poor contact of the terminals, etc, before troubleshooting.
4. After troubleshooting, erase the DTC and test-drive the car. Be sure that the ABS indicator light does not come on.
5. The connector illustrations show the female connectors with a single outline and the male connectors with a double
ouflrne.
6. The connector terminal cavities containing female terminals are always numbered by looking at the connector from
the wire side. and the cavities containing male terminals are always numbered by looking at the connector from the
terminal side.
r'
19-55

Diagnostic Trouble Code (DTCI
Symptom-to-System Chart
DTC
oH1=DIAGNOSIS/SYMPTOM
DETECTION TIMING
>=PNOBABLE CAUSEi.'sEV98€E
zr\9=6<_6
=t
6tz
NODTC
ABS indicator iighr doesnot com€ on when ignirionswrt.h is lu.ned on (ll)
, Open in the pow€. source circ!ir ror the ABS -.ndicato;l isht. Elown ABS indicalo.lighr butb' Open in rhe ABS indicaror tight drive cncuit.. Shori ro pow€r in theWALpcircuit. FaultyABS contrct!nit
ONABS indicator light doesnol90 oft 6frer engine isOpen in the lG2 circuitOpon in the +B circuirOp€n andlor short ro body ground jn the WALP circuitFaultv AAS coni.ol unnt1
oN.Wheel sensor (op€n/shortOooo13upen, snofiro bodyground and/or shodro power in rhe wh€61
Faulty ABS co.lrctunitllBL12
oN.(chipp€d pulser gea/noise)oao
Short to wh6sls€n6or (O)circuir in t'e.h;;Go-nso, trtcircutiFaulty whsel s€nsor insra|ation
Faulty ABS cont.olunir
I8
31
ONSolenoid (open/shon roaoa
Op.ni shon to bodyground and/o. shorrto powsr in rhe
op€n in lh6 coM circuit
Faulty ABS conlrclunit
32F8-OUTFL.IN3'lFT.OUTRF.IN88 OUT318t rN38RLOUT
ONoo
op€n in tho motor pow€..ourco circliaOp€n inih€ moro.cNOcircuit
Faulty ABS conrrol unit
52ONoo
Open in rh€ COM, PMR 6nd/o. MCKcircuirOp€n.n.Vor blown lus€ in the under hood AgS rusdretry box
Faufty pump moto. rotayfaulv ABS conlrolunit
53ONo
. Sho.tto bodygrou.d in the pMR circuit. Shon to powsr in tha puhp moror pow6rsource circu. r.urty pump motor.etay, FalltyABS contolunit
54ONooc
Open, rhorr ro bodygrcund and/or blown fus€ in the B1 or 82
Shonto body ground.n.Vor short to powor in rhe COM circuitFaulty modul.tor unnFaulty ABS controt unit
ONlgnition voltage (low vott-oooo
. Connection ot the24 V bariorv tor enqins starr. Faurtycharoins system. Op€n in th6lG2 circuit. Fa!lly ABS contrcl unil
81ONCPUoooo
E {€rml facior{sl en bs rhe ouse{sl ot |he probtemF.ulty ABS conrrot unit
r: It DTcs 1 1 18 {wheel sensor codes) wore del*ted the lasr time the v6h cls wEs d riv€n, rhe a8s indicator tight wi

stay on u ntit lh6 ignition swirch is rurn6d oN t), and theconnorunit contnms rhat rhe wheet sensoB . rc OK,
19-58

Le
\.t
CONDITION FOR DETECTION
MANAGEI\,4ENT
FEFERTOPAGEDUNINGABS CONTFOLEXCEPTABS CONTAOL
19-60
19-62
The ABS indicator lighl cones on when vehicle is stopp€d and wheel sensor a given vohaqe does nol
19 64
The ABS indicaror comes on under th€lollowing conditions.When morethan one otwheels are a standstiland thelelocirv otthe fastest wheel reaches a
' fohen th. velocity of the faslesl wheel reaches or exceds a given sped, and it there ar€ somewh@lswhose velocity is slowe.lhan a cenain percenlage oi lh€ fast6t wheelsped for 3 given period. when rhere are lemporary open or short ctcuits ol rhe wheel sonsor' chipp€d pulser gear, orsrgnalorslJrbaaLe
19 64
The main relay repeats ON/OFF switching atalltimes.WhenthemainrelayisON,ashortt$tpulseissentloeachvalve lfthere s some dis'repa ncv, lheABS indicalor lightcomes on.. When rhe main relay is OFF, a shonl€sl pulse is s€nlto each valve lfth6 solenoid drive voltage rsout ol a qiven range, the ABS ndicalor lighl comes on19-66
'The pump nolot s activaled orc€ o' Mrce sfier every gn't'on sw'lch ON (ll) operarion whrle lte -^vchicle acLelerales lrenthemolorotivevo'taSersrhecled When lhevolla96 rs abnormar,lre Absindicaror llghl comes on.. Afte. ABS ;onl rol com pletion, the moror isswitched ofi 6nd the main CPU checks the molor dnvevoltase. when rhe vortase is abnormsl, the ABS indicato49!!!99!:l!:_-
19-68
D!rino an active motor lesl or AAS control,lhe main CPU checks ihe supplv voltage to the motor'whe;lhe vohage s abnofmal, the ABS indicator lightcomes on19,68
lirhe moror drvevoltage indicates molot operalion when the main cPU does notswilch the motoroN, rhe ABs indicaro. comes on19-64
. Wh"" " ".1"".1d ""1r. f"llure is detecred, the CPU checksth€ voltage ofthe main rel6v output lllhevohaqe is lowerthan 6 given vohage, theABS indicator light comes on. The ;ain r€lay repeats ON/OFF switching ar a!ltimss when the main rel.v is ofi, a shorl l6st pulse
is sent ro €ach valve. The CPU mon tors the reJer€nce vohage ll the vohage is out ot a g iven range'
the ABS indic.tor lightcomes on
19 71
wt'",, rt'e lgnitlon rottag" is ower or higherthan a given voltage,lhe CPU inhibils ABSlonlrolandswirches oli the ma in relaY, 6nd the ABS indicaror lig ht com€s on When the ig n ilion vohage recove'sto normal f6ng6, ABS inhibition is canceled.19.73
rimln CpU anO suU CeU ch€ck each other undercertain condnions. Whon rhe CPUS dstectthe fol'lowing discrepanaies, rhe ABS indicator light comss on. whe; rh€re is discGpancv n lhacarculated wheelspeed velocirv thar continuosJor more than a given
.i^/hen rhere is discrcoancv in the ehase informalion lhat continuesfor morerhan a given period' When rhere is discrepancY in thecalculared conlfol pa.amerer'. When thewatch dog conrrolp!lsetailslof a given penod. When th6 checkotth€ ROM tai1s.. when there is disrepancy inrhe data roading.nd wriung prcledurc ot RAM
19 7'l
tr
19-59

Troubleshooting
ABS Pump Motor
Diagnostic Trouble Codo {DTC} 51-53r ABS pump Motor Diagnosis
YES NOTE: Short the PMR terminat to body
NOTE: Reinstall ground for a moment, and recheck the fuse.
the fuse if it is OK lf the fuse is blown, check for a short to bodyground in the MCK circuit.
AAS CONTNOL UNIT 22P CONNECTOR
7At0tl
1211192l22
PMR IYEL/RED} I JUMPERI WIRE
Wire side of female terminals
NO
NO
YES
NOTE: Reinstallthe fuse if it is OK.
NOTE: Short the PMF terminal to booyground for a moment, and recheck the fuse.lf the fuse is blown, check for a short to bodyground in the wire between the under-hoodABS luse/relaV box and pumD motor.
- With the ignition switch ON(ll), ABS indicator lighr doosnot go otf.- With tho SCS s€rvico conneetor conn€cted lsee page 19661,OTCa 51-53 aro indicated.
Check the MTR CHECK (7.5 A) fuse.
Repl.ce the fuse .nd recheck.
Replaco tho tuse and rocheck.
Rcphce th€ pump motor rol6y.
Check the pump motor powersource circuit:Turn the ignition switch ON (ll).
Ch€ck for a short to !'ows. in thopumP motor power 3ource ciacrrit:Remove th6 purnp motor relay,
Does the pump motor operate?
Bopair sho.t to powsr in the wir€botwoen the under-hood A8Stuse/.elay box and ABS pumpmotor.
Does the pump motor operate?
Check tor loGe ABS control unitconnoctors. lf nocessary, substi-tute a known-good ABS controlunit and roch€ck,
(To page 19-69)
19-68