1996 HONDA CIVIC relay

Gircuit Diagram
MOOULATOR UNIT IOP CONNECTOR
zrJrF!_lll 2 3ll
14TiEltl
c@4
PIMP MOTOR 2P CONNECTOR(Ll number)fFlGTN
UNDER.HOOO A8S FUSE,/FELAY BOX3P CONNECTOR (O number)
| 2 3l
UNDER.HOOD AAS FUSE/RELAY BOX2P CONNECTOR (! number)
| -l
GAUGE ASSEMELY 5P CONNECTOR
---t--t1 t/ 13 )/l5l
Wire side ot temale terminals
- E8l{'Ytr
AA DEF BLY I7.5AI
_@f_u,
n4@f-n,
LEFT.FSONT SOLENOIO
UNDER-OASH FUSSRELAY 8OXZoP CONNECTOR (O numbe,
235678It0tlt3/ i15 /t820
UNDER.OASH FUSE,/RELAY BOX18P CONNECTOR (E numb€r)
23569ll213)t4 /1617
19-50

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

Troubleshooting Precautions
ABS Indicator Light
I The ABS indicator light comes on when the ABS control unit detects a problem in the system. However, even thoughthe system is normal, the ABs indicator light can come on, too, under the following conditions. To determine theactual cause of the problem, question the customer about the problem, taking the following conditions into consider-ation.
. Signal disturbance
. Wheel soin
. Only drive wheels rotate. Battery voltage fluctuates
2. When a problem is detected and the ABS indicator light comes on, the indicator light can stay on untat the ignitionswitch is turned off, or it can automatically go off, depending on the mode.. Lightstayson until the ignition switch isturned off;When the system is inthesvstem down mode.o Light automatically goes off:When the system is in the control inhibition mode.(refer to symptom-to-system chart)3 The ABS indicator light stays on when the system is reactivated without erasing the DTC, but it goes off after startingthe car.
when the wheel sensor system is faulty and the ABS indicator light comes on, the algorithm of the system automaticallyturns off the ABS indicator light after the wheel speed signal returns to the normal speed. while, when the DTC is erased,the CPU is reset and the ABS indicator light goes off when the system check€d out normal by the initial diagnosis.Therefore, test-drive the car after servicing the wheel sensor system, and be sure that the ABS indicator light does notcome on.
4. When the ABS control unit outputs battery voltage to the gauge assembty, the ABS indicator light goes off.
Diagnostic Trouble Code (DTC)
1. The diagnostic trouble code (DTC) is memorized when a problem is detected and the ABS indicator light does not gooff, or when the ABS indicator light comes on.The DTC is not memorized when the ABs indicator right comes on unress the cpU is activated.2. The memory can hold any number of DTCs. However, when the same DTc is detected twice or more, the later one iswritten over the old one.
Therefore. when the same problem is detected repeatedly, it is recorded as one DTC.3. The DTCS are indicated in the order of ascending number, not in the order thev occur.4. The DTCS are memorized in the EEpROM {non-volatile memorv}.Therefore, the memorized DTCS cannot be canceled by disconnecting the battery. perform the specified orocedures toerase.
Solf-diagnosis
1. The self-diagnosis can be classifield into these four categories:' Initial diagnosis; Performed right after the engine sta rts and untiltheABs indicator light goes off.o Except ABS control: Performed when the ABS is not functioning,. During ABS control: Performed when the ABS is functioning.. During warning: Performed when the ABS indicator light is ON.2 The system performs the following controls when a problem is detected by the self-diagnosis:. ABS indicator light ON. Memory of DTC
. Mode change to the "system down mode,, or the "control inhibition mode,,.
MODEABS INDICATOR LIGHTMAIN
RELAY
SOLENOID
VALVECPURestart conditionDTC
SYSTEM
DOWNONNo
operal|on
Drive
inhibitionOperation+rlgnition
switchOFF - ONMemory
CONTROL
INHIBITIONONNo
operat|on
Orive
inhibitionOperationAutomaticMemory
*1: Except CPU failure
19-54

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 Indicator Light Does Not Come On
YES
NOTE:Reinstallthefuse if it is OK.
The A8S indicator light does not come on when ignition switch is turned ON ll.
NOTE: All indicator tights except the charg,ing system light will not come on when theMETER 17.5 A) ft se is btown.
NO
GAUGE ASSEMBI"Y 5P CONNECTOR
Wire side of female terminals
Tho ABS indicator light does notcome on wh€n ignition switch istu.ned ON {lll.
check the METEB (7.5 A) fuse inthe under-dash fuse/relay box.
Beplace the tu3e and recheck.
Check for an open in th6 lcl cir-cuii:1, Disconnect the gauge assembly 5P connector.2. Turn the ignitjon switch ON l).3. Measure the voltage betweenthe gauge assembly 5P con-nector terminal No. 5 andbody ground.
. Ropair opan in tho wirobotwe€n thc METER t7.5 Attuso and gauge .$cmbly.. Roplacc th. und.r-dash tus./r.l.y box. lop.r cirouit in3idothe box.l
ls there baftery voltage?
Check the ABS indicator lightbulb in the gauge assembly.
ls the bulb OK?
Ch€ck tor a short to power in theWALP circuit:Measure the voltage between thegauge assembly 5P connectorterminal No. I and body ground.
Replir short to power in tho wiiGb.tweon the gruge rs3embly.nd ABS control unh.
ls there battery voltage?
lTo page 19-61)
19-60

Troubleshooting
The ABS indicator light does not go off after the engine is started.
- With engine running, ABSindicator light is ON.- With tho SCS sewice connec-to. connected l3oe page 19-561,no DTC is indicated,
Checkthe RR DEF RLY {7.5 A)tusein the under-dash fuse/relay box.
Raphco tha furo and rochack.
Check the ABS +B (20 A) fuse inthe under hood tuse/relay box.
R6pl.ce tho tu3c lnd r.ch.ck.
Chock for an open in the lG2 cir-GUrt:1. Turn the ignition switch ON (lt).2. Measure the voltage betweenthe ABS control unh 26P con-nector terminal No. 3 andbody ground.
Bopair opcn in tha wir. botw.cnth. RR DEF RLY 17.5 Al tus. .ndABS control unit.
Check tor an opon in thG Bl end82 circuit:Measure the voltage betweenbody ground and terminals No. 14and No. 15 individually.
Rrpair opsn in tha wiro t atwa,anthe ABS +B (20 Al fu.r .nd ABScontrol unh.
ls there banery voltage?
1To page 19-63)
ABS Indicator Light Does Not Go Off
YES NOTE: Feinstattthe luse it it is OK.
YES NOTE: Reinsta

the fuse if it is OK.ABS CONTROL UNIT 26P CONNECTOR
IG2IELK/BLUI
Wire side of female terminals
ABS CONTBOL UN]T 26P CONNECTOR
8T IWHT/GRNI
Wire side of temale terminals
19-62

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

tt
(From page 19-68)UNDER.HOOD ABSFUSE/RELAY 8()X
TERMINAL TERMINAL
PUMP MOTOR 2P CONNECTOR
MOTOR +8 lWHTl,$
rv) -
Y
Wire side ot female terminals
\lt
MOTOR +B {RED}MOTOR GND (BLK)
ABS CONTROL UNIT 22P CONNECTOR
(cont'dl
19-69
JUMPER WIRE
Wire side oI female terminals
Check the pump motor circuit:1. Remove the pump motor relay.2. Turn the ignition switch ON (ll).
3. Connect the pump motor relayconnector +8 and MOTOR terminals with a iumper wire tora momenr,
Ch€ck for an open in the pump
moior +B circuit:1. Turn the ignition switch OFF.2. Disconnect the pump motor2P connector,3. Turn the ignition switch ON (ll).
4. Connect the pump motor relayconnector +B and MOTOR ter-minals with a jumper wire.5. Measure the voltage betweenthe pump motor 2P connectorterminal No. l and bodyground.
Does the pump motor operate?
Repaia open in the wire botweentho under-hood ABS fuse/relaybox and pump motor.ls there battery voltage?
Check the pump motor opgra-tion:Connect the battery {+}terminal tothe pump motor 2P connector ter-minal No. 1. and the (-)terminalto
the terminal No. 2 for a moment.
ReDlaco lho modulator unit.(Feulty pump motor)Does the pump motor operate?
Chock for a short to body ground
in the PMR circuit:1. Turn the ignition switch OFF.2. Disconnect the ABS controlunit 22P connector.3. Check for continuity betweenterminal No. 19 and bodygrouno,
Repail opon in ths wirg botwgentho pump motor and bodv ground,
or poor ground (G,!09).
Ropair 3hort to body g?ound intha wire between the under-hood ABS fuse/rclay box andABS cortrol unit.
(To page 19-70)