
Wheel Sensor
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
at LOW SPEED
wheel Sp€od and Modulatot Control
VEHICLE SPEED
VEHICLE SPEED
WHEEL SPEED
PRESSU
OUTLETVALVE ON
OFF
INLETVALVE ON
OFF
MOTOR
ON
OFF
When the wheel speed drops sharply below the vehicle speed, 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 caliDer fluid oressure.
F
GEAR PULSER
19-31
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ABS Control Unit Terminal Arrangement
ABS CONTROL UNIT 26P CONNECTOR
Wire side of female terminals
TeiminalnumbelWiiecolorTerminal3ignTeiminalnamglDescription
Voltrge
tdminalsCondhions(lgnition Switch ON llll)Output voltago
1GRNn/VHTPCOM(Primary
common)
Power source for the solenoidvalve and pump motor.1-GNDON6
ONOV
OFFAC:3-6V
2BLI(WHTSCOM(Secondary
common)
Power source for the solenoid2-GNDOFF
lConnect the SCS seNice] connector IApprox.3 V
BLVBLU(lgnition 2)Detects ignition switch 2signal. (System activate signal)3-GNDBattery Voltage
4BLUA/ELRRO(Rear-right 0)Detocts right-rear wheelsensor srgnat.When the wheel isturned at 1 turn/second.
53 mV or above ondigitaltester (ACrange) {Beference)150 mvtrp or aboveon oscilloscope
GRYRLO(Rear-left 0)Detects left-rear wheel sensorsrgnat.6-19
8GRNFRO(Fronr-right 0)Detects right-front wheelsensor signal.8-21StopsApprox.2.5 VSTOP
{Stop)Detects bfake switch signal.(Prevents unnecessary ABS operation)9-GNDBrake pedal pressed.Battery Voltage
Brake Dedal released.OV
10BRN^/VHTFLO(Front-left 0)
Detects left-front wheel sensorsrgnal.
10-23
When the wheel isturned at 1 turn/second.
53 mV or above ondigitaltester lACrange) (Reference)
150 mvpp or aboveon oscilloscope
StopsADprox. 2.5 V
YELRL-oUT(Rearleft outlet)
Drives left-rear outlet solenoid12.GNDONONOV
OFFAC:3-6V
13RED^/vHTRR.IN(Rear-right
inlet)
Drives right-rear inlet solenoid13.GNDOFF
lConnect the SCS service\ connector IApprox. 3 V
14WHT/GRNB1(Baftery 1)Power source for the solenoidvalve and pump motor.14.GND
Every timeBattery Voltage82(Battery 2)Power source for the solenoidvalve and pump motor.15-GND
16BLKGND2(Ground 2)Ground for the ABS controlunit.16-GNDBelow 0.3 V
't7GRN/YELRR1(Rear-right 1)Detects right-rear wheelsensor signal.'t7 -4
When the wheel is turnedat l turn/second,
53 mV or aboveon digitaltester(AC range)(Reference) 150mVp-p or aboveon oscilloscope
19LT BLURL1(Rearieft 1)Detects left-rear wheel sensorsignal.19-6
GRN/BLKFR1(Front-right 1)Detects right-front wheelsensor srgnat.21-8
23GBN/ORNFL1{Front-left 1}Detects left-front wheel sensorsagnal.23-10StopsApprox. 2.5 V
REDRLI N(Rear-left inlet)
Drives left-rear inlet solenoid
25,GND
ON
=
-9ONOV
AC:3-6V
OFF
/Connect the SCS service] conneclor IApprox. 3 V
26BLKGND3(Gtound 3)Ground tor the ABS controluntI.26-GNDBelow 0.3 V
19-34
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ABS CONTROL UNIT 22P CONNECIOR
Wire side ol lemale terminals
TerminalnumDerWirecolorTerminal 3i9nTerminal nameDescription
Voltage
Conditions(lgnition Switch ON (ll)lOutput voltagetominals
1RED/BLUFR-IN(Front-right
inlet)
Drives right-front inletsolenoid valve.
1-GND.9otur
ONIONOV
OFFAC:3-6V
OFF
lconnect the SCS servicel
connedor lApprox.3 V
BRN(Service checksignal)
Detects service check signal(Diagnostic trouble codeindication)4.GND
SCS service connectorconnected.OV
SCS service connectordisconnected.Approx. S V
7BLU/RED(Warning
ramp)
Drives ABS indicator {The indi-
cator goes off when ABS con-
trol unit outputs battery volt-age).
7.GND
lndicator ONApprox. 2 V
lndicator OFFBattery Voltage
10YEUBLKFL-OUT(Frontieft
outlet)
Drives left-front outletsolenoid valve.1O-GNDON
=
I
ONOV
OFFAC:3-6V
l'lRED/BLKFL-IN(Front-left inlet)
Drives left-front inlet solenoid11-GNDOFF
lconnect the SCS servicq connector lApprox.3 V
YEUBLUFR-OUT(Front-right
outlet)
Drives right-front outletsolenoid valve.12-GND
14LT BLU(Data linkconnectod
Communicates with HondaPGM Tester.14-GNDApprox. 5 V
17BRN/YELMCK(Motor check)
Detects PumP motor drivesignal.17-GNDPumpmotorrelay
ONBattery Vollage
OFFOV
19YEUREDPMR(Pump motorreray,
Drives pump motor relay.
19.GNDcl)
ON6IONOV
OFFAC:3-6V
OFFponnecl the SCS service]
connector IApprox.3 V
BLURR-OUT(Rear-right
outlet)
Drives right-rear outletsolenoid valve.
21.GND'a)
ONPumpmororrcray
ONOV
OFFAC:3 6V
OFF
lconnect the SCS service] connector lApprox.3 V
BLKGND2(Ground 2)Ground for the ABS controlunit.22.GNDBelow 0.3 V
19-35
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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. The ABS control unit operates the solenoid valve when the brake pedal is released after the initial diagnosis You may
hear the solenoid valve operate at this time, but it is normal
Pumo Motol
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 motor operate at this
time, but it is normal.
Brake Fluid Replacement/Ail Bleeding
L Brake fluid replacement and air bleeding procedures are the same as for vehicles without ABS To ease bleeding, start
with the front wheels.
Troubleshooting
1. The troubleshooting flowchart procedures assume that the cause of the problem is still present and the ABS indicator
is still on. Following the flowchart when the ABS indicator does not come on can result in incorrect diagnosis.
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
acceleration, during the specified vehicle speed, etc. Therefore, the symptom canngt be checked unless the check
conditions match with the problem conditjons
3. When the ABS jndicator does not come on during the test-drive. but troubleshooting is performed based on the DTC,
check lor loose connectors, poor contact of the terminals, etc., before you start troubleshooting.
4. After troubleshooting, erase the DTC and test-drive the vehicle. Be sure the ABS indicator does not come on.
5. The connector illustratjons show the female terminals with a single outline and the male terminals with a double out-
l ne.
ABS Function Test
To simulate ABS operation and activate the solenoid valves and pump, use the Honda PGM Tester.
Connect the PGM Tester to the 16P Data Link Connector (DLC). When the System Select menu is displayed, select the ABS
Test Mode menu, and follow the tester's prompts.
19-37
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DTC 51 - 53: ABS Pump Motor
NOTE: Short the PMR terminal to bodyground for a moment, and rochock the tuse.lf the fuse is blown, check lor a shon to bodyground in the MCK circuit.
NOTE: Short the PMR terminal to bodyground for a moment, and recheck the fuse,lf the tuse is blown, check tor a short to bodyground in the wire between the under hoodABS fuse/relay box 6nd the pump motor.
ABS CONTROL UNIT 22P CONNECTOR
Wire side of female terminals
(cont'di
- Wilh the ignition switch ON{ll), the ABS indicator doesnot go ott.- With the SCS seruico connec-tor connoctod {sce page 19381,DTCa 51 - 53 .re indicated.
check the MTR cHEcK (7.5 Ailuse in the under-hood ABStuse/relay box, and reinstall theluse if it is OK.
Rsplace the fuse and rech6ck.
check the PUMP MOTOR (40 A)fuse in the under-hood ABS fuse/relay box, and reinstall the fuse ifit is oK.
Roolace lhe tusg and rocheck.
Feplace the pump motor r6ley.
Check the pump motor powelsourc€ circuit:Turn the ignition switch ON (ll).
Ch6ck fo. a short to oowd in th6pump motor power sourca circuit:Remove the pump motor relay.Does the pump motor operate?
Repair rhort to power in the wirebclweon the under-hood ABSfuse/.6lay box and ihe ABSpump motor.
Does the pump motor operateT
Ch6ck tor loos6 ABS control unitconnectors. lf necotsary, 3ubsti-tute . known-good ABS controlunit and rocheck.
(To page 19 50)
19-49
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Troubleshooting
DTC 51 - 53: ABS Pump Motor (cont'dl
(From page 19 49)
UND€R-HOOO ABSFUSE/REI-AY BOX
MOTOR +B IREDIMOTOR GND IBLKI
TERMINAL TERMINAL
PUMP MOTOR CONNECTOB
Fr MOTOR +B {WHTI12 lF-(v)vI
Terminal side of female terminals
Terminalside ofmaleterminals
ABS CONTROL UNIT 22P CONNECTOR
JUMPER WIRE
Wire side of female terminals
Chock the pump motor ci.cuit:1. Remove the pump motor relay.2. Turn the ignition switch ON {ll).3. Connect the pump motor relayconnector +B and MOTOR ter-minals with a jumpor wire fora moment,
Check for an open in the pump
motor +B circuit:1. Turn the ignition switch OFF.2. Disconnect the pump motor
3. Turn the ignition switch ON (ll).
4. Connect the pump motor relayconnector +B and MOTOR terminals with a iumper wire.5. Measure the voltage beaveenthe pump motor connectorterminal No. l and bodygrou nd.
Does the pump motor operate?
Bepair opon in the wire botweenthe under-hood ABS fuse/relavbor and the pump motor.ls there battery voltage?
Check the pump motor opera-tion:Connect the battery (+)terminal tothe pump motor connector termi-nal No. 1, and the (-) terminal tothe terminal No. 2 for a moment.
Reolace the modulator unit.
lFaulty pump moto.lDoes the pump motor operate?
Ch6ck for a short to body groundin the PMR circuit:1. Turn the ignition switch OFF.2. Disconnect the ABS controlunit 22P connector.3. Check tor continuity betweenterminal No. 19 and bodyground.
Repair open in the wire bstweenthe pump motor and body ground,
or poo. ground {G3511.
Repair short to body ground inthe wir6 botween the under-hood ABS tuse/rclay box and th€ABS contlol unit.
{To page 19-51)
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(From page 19-50)
Chcck for .n opsn in the PCOMcircuit:1. Turn the ignition switch OFF.2. Reconnect the ABS controlunit 22P connector.3. Connect the SCS service con-nector.4. Turn the ignition switch ON {ll).5. Measure the voltage betweenthe pump motor relay con-nector PCOM terminal andbody ground.
Repair opon in the wire betwoenthe under-hood ABS fuse/relaybox and tho ABS conlrol unh.ls there approx.3 V?
Check for an open in tho PMR cir-cuh:Measure the voltage between theABS control unit 22P connectorterminal No. 19 and body ground.
Ropair open in tho wir6 botwagntho undcr-hood ABS fuse/rolaybox .nd the ABS control unit.ls there approx. 3 V?
Ch.ck tor an opon in the MCKci.cuit:1. Turn the ignition switch OFF.2. Disconnect the SCS serviceconnector.3. Turn the ignition switch ON (ll).
4. Measure the voltage betweenthe ABS control unit 22P connector terminal No. 17 andbody ground while connect-ing the pump motor relayconnector +B and MOTOR ter-minal with a jumper wire tormoment,
Repair open in the wiro bdtweenthe under-hood ABS fus6/telaybox .nd the ABS control unit.ls there battery voltage?
Chock for loose ABS control unitconnectoas, It necsssary, substi-tule a known-good ABS controlunit and aocheck.
tr) l--l
r"r
ABS CONTROL UNIT 22P CO NECTOR
Wire side of female terminals
1t011
MCK IBRN,/YEL}
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![HONDA CR-V 1997 RD1-RD3 / 1.G Workshop Manual
Troubleshooting
DTG 54: Main Relay
IWHT/GRNI
AAS CONTROL UNIT 26P CONNECTON
Wire side of female terminals
ABS COf{TROL UN]T 22P CONNECTOR
PCOMIGRN/WHTIscoM{BLK/WHTI
Wire side of female terminals
- Wi HONDA CR-V 1997 RD1-RD3 / 1.G Workshop Manual
Troubleshooting
DTG 54: Main Relay
IWHT/GRNI
AAS CONTROL UNIT 26P CONNECTON
Wire side of female terminals
ABS COf{TROL UN]T 22P CONNECTOR
PCOMIGRN/WHTIscoM{BLK/WHTI
Wire side of female terminals
- Wi](/manual-img/13/5778/w960_5778-974.png)
Troubleshooting
DTG 54: Main Relay
IWHT/GRNI
AAS CONTROL UNIT 26P CONNECTON
Wire side of female terminals
ABS COf{TROL UN]T 22P CONNECTOR
PCOMIGRN/WHTIscoM{BLK/WHTI
Wire side of female terminals
- With the ignition switch ON(lll, the ABS indicator doesnot go off.- With the SCS service connec-tor connected {see page 19-381,DTC 54 is indicatod.
Check the ABS +B 120 A) fuse inthe under-hood ABS luse/relaybox, and reinstall the fuse if it isoK.
FeDlace the tu3e and recheck.
Ch€ck tor an open in the 81, 82circuit:Measure the voltage betweenbody ground and the ABS controlunit 26P connector terminal No. 14and No. 15 individually.
Repair open in the wiro bstweonth6 ABS conirol unit and theunder-hood ABS fuse/rolay box,
ls there battery voltage?
Check for a short to body groundin the PMR circuit:L Turn the ignition switch OFF.2. Remove the pump motor relay.3. Disconnect the ABS controlunit 22P connector.4. Check lor continuity betweenterminal No. 19 and bodygrouno.
Repair short to body ground inthe wire betweon the under-hood ABS lGe/r.lay box and theABS control unit.
Check for a short to body groundin the PCOM, SCOM cilcuit:1. Disconnect the ABS controlunit 26P connector.2. Check tor continuity betweenbody ground and the ABS con-trol unit 26P terminals No- 1and No.2 individually.
. R€pair short to body ground inth€ P1COM circuit wire betweenthe ABS control unit and theund6r-hood ABS tuse/r6layoox.. R6p.ir short to body ground inthe PCOM or SCOM circuit wirebetweon th6 ABS control unitand lhe mod!lator unit.. R.Dlece tho modulrtor unit.(Short circuit inside the unitl
ls there continuity?
(To page 19-53)
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