2003 HONDA CIVIC under-dash

Control Unit Input Test
l.Before testing, troubleshoot the multiplex control system lsee page 22-jj2).
Remove the dashboard lower cover,
Disconnect the under-dash fuse/relay box connectors B, G, J, X and y
NOTE: All connectors are wire side of female terminals.
UNDER-DASH FUSE/RELAY BOXCONNECTOR B I6PIUNDER.DASH FUSE/RELAY BOXCONNECTOR G {1OP)
2.
3.
UNDER-DASH FUSE/RELAY BOXCONNECTOR J {8PI
l-,1 - llTtlF_j-JF-#
141516 7l8l
WHT/BLU
\
l-,1 - l-rl€ll
lslrlzlol
\BLU/RED
UNDER.DASH FUSE/RELAY BOXCONNECTOR X I8PI
4. Inspect the connector and socket terminals to be sure they are all making good contact.
. lf the terminals are bent, loose or corroded, repairthem as necessary, and recheckthe system.. lf the terminals are OK, goto step 5.
(cont'd)
BLU/WHT
BLU/BLK
22-141

Wipers/Washers
Control Unit Input Test (cont'dl
5. Reconnect the connectors, and make these input tests at the connector.
.lfanytestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem.
.lfalltheinputtestsproveOK,themultiplexcontrol unit must be faulty. Replace the under-dash fuse/relay box
assembly.
CavityWireTest conditionTest: Desired resultPossible cause if result is not obtained
J4BLKU nder all
conditlons
Check for voltage to ground: . Poor ground (G501)
There should be 1V or less. . AnoDeninthewire
Y6BLKU nder all
conditions
Check for voltage to ground: . Poor ground (G502)
There should be 1 V or less. . An oDen in the wire
BIWHTiBLUlgnition switch ON
{ll) and washer
switch ON
Check for voltage to ground:
There should be battery
vortage.
Blown No. 20 (20A) fuse in the
under-dash fuse/relay box
Faulty wiper/washer switch
An open in the wire
E'0BLU/REDlgnition switch ON
(ll) and wiper
switch OFF (wiper
motor stopped)
Check for voltage to ground:
There should be battery
voltage.
Blown No. 20 (20A) fuse in the
under-dash fuse/relay box
Faulty wiper/washer switch
Faulty windshield wiper motor
An open in the wire
G7BLUA/VHTlgnition switch ON(ll) and wipers in
park position
Check for voltage to ground:
There should be battery
voltage.
Blown No.20 (20A)fuse in the
under-dash fuse/relay box
Faulty windshield wiper motor
An ooen in the wire
x1BLU/BLKlgnition switch ON(ll) and wiper
switch in INT
Check for voltage to ground:
There should be battery
voltage.
Blown No.20 (20A)fuse in the
under-dash fuse/relay box
Faulty wiper/washer switch
An oDen in the wire
\J
\J
L
22-142
J

Accessory Power Socket
Circuit Diagram
22-149
Accessory Power Socket Test/
Replacement
1.
4.
Carefully pry the accessory power socket (A) out
from the center lower cover.
Disconnect the 2P connector (B) from the socket.
Inspect the connector terminals to be sure they are
all making good contact.
. lf the terminals are bent, loose orcorroded,
repairthem as necessary, and recheck the
system.. lf the terminals look OK, go to step 4.
Turn the ignition switch ACC (l), and check for
voltage between the No. 'l and No. 2 terminals.
. There should be battery voltage.. lf there is no banery voltage, checkfor:- poor ground {G502).- an open in the wire.- blown No. 18 (15A)fuse in the under-dash
fuse/relay box.

Keyless/Power Door Lock System
Keyless Receiver Unit Input Test (cont'dl
With the connector still disconnecled, make the input test at the connector.
.lftestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem.
. lf the inputtest proves OK, goto step 6.
Reconnect the 5P connector, and make these input tests at the connector.
.lfanytestindicalesaproblem,findandcorrectthecause,thenrecheckthesystem.
. lf all the inputtests prove OK, replacethe keyless receiver unit.
CavityWireTest conditionTest: Desired resultPossible cause il result is not obtained
2BLU/ORNUnder all
conditions
Check for continuity between
the No.2 terminal and the
No. 2 terminal ofthe
under-dash fuse/relay box
connector K { 17P).
There should be continuitv.
An open in the wire
CavitvWireTest conditionTest: Desired resultPossible cause if result is not obtained
1BLKUnder all
conditions
Check for voltage to ground:
There should be 1 V or less.
. Poor ground (G502)
. An oDen in the wire
YELlgnition switch
oN (||)Check for voltage to ground:
There should be battery
voltaqe.
Blown No. 10 {7.5A) fuse in lhe
under-dash fuse/relay box
An ooen in the wire
WHT/REDUnder all
conditions
Check for voltage to ground:
There should be battery
voltaqe.
' Blown No.9 (10A) fuse in the
under-hood fuse/relay box. An ooen in the wire
22-154

Control Unit Input Test
1. Before testing, trou bleshoot the m u ltiplex contro I system (see page 22-172).
2, Remove the dashboard lower cover.
3. Disconnect the under-dash fuse/relay box connectors.
NOTE: All connectors are wire side of female terminals.
UNDER.DASH FUSE/RELAY BOXCONNECTOR C {1itPlUNDER.DASH FUSE/RELAY BOXCONNECTOR F I12P)
UNDER.DASH FUSE/RELAY BOXCONNECTOR M Il2PI
UNDER-OASH FUSE/RELAY BOXCONNECTOR J {8PI
UNDER.OASH FUSE/RELAY BOXCONNECTOR P I18PIUNDER.DASH FUSE/RELAY BOXCONNECTOR K {17PI
BLU/ORN
UNDER.DASH FUSE/RELAY BOXCONNECTOR O (8P)
YEL/BLK YEL/BLK YEL YEL
UNDER-DAsH FUsE/neLeY sbxCONNECTOR X (8P)
YEL YEL/BLK
UNDER.DASH FUSE/RELAY BOXCONNECTOR Y {13P)
,/1,/34568
LT GRN/REDWHT/BLK YEL/RED WHT/GRN WHT/BLU
4. Inspect the connector and socket terminals to be sure they are all making good contact.
. lf the terminals are bent, loose orcorroded, repairthem as necessary, and recheckthe system.. lf the terminals look OK, go to step 5.
(cont'd)
GRN
BLU/REDBLU
RED/WHT
22-155

Keyless/Power Door Lock System
Control Unit Input Test (cont'dl
5. Reconnect all connections to the underdash fuse/relay box, and make these input tests at the appropriate connectors on the under-dashfuse/relay box.
'lfanytestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem.. lf all the inputtests prove OK, goto step 6.
CavitvWireTest conditionTest: Desired resultPossible ca use if result is notobtainedc1'l8LUUnder all conditionsAftach to ground:Parking, side marker, licenseplate lights, and tajllights shouldcome on.
Blown No.2 (15A)fuse in the underhood fuse/relay boxFaulty taillight relayFaulty under-dash fuse/relay boxAn onen in rhc wireBLU/BEOUnder all conditionsAttach to ground:Headlights should come on.Blown No. 15 or 17 (15A)fuse in theunderhood fuse/relay boxFaulty headlight relay '1 or 2An ooen in the wireJ2WHT/REDUnder all conditionsCheck for voltage to ground:There should be battery voltage.Blown No.9 (15A)fuse in the under-hood fuse/relay boxAn oncn in thc wircBLKUnder all conditaonsCheck for voltage to ground:Thcre shouln hc 1 V or lpqsPoor ground (G501)An ooen in the wireJ6OBNUnder allconditionsAttach to ground:The horns should sound.Blown No. 7 (15A)fuse in the underhood fuse/relay boxFaulty horn relayFaulty hornsAn 6nen in rhe wireJ7Under all conditionsCheck for voltage to ground:There should be battery voltage.Elown No. 16 (20A)fuse in the underhood fuse/relay boxAn oocn in ihc wi.cP18BEDHatch openCheck for voltage to ground:There should be 1 V or less.Poor ground (G552)Faulty hatch latch switchAn oncn in rhc wirFHatch closedCheck for voltage to groundlThere shoul.l he 5 V or moreFaulty hatch latch switch
GBNDriver's door openCheck for voltage to g.ound:There should be 1 V or less. Faulty driver's door switch. An ooen in the wireDriver's door closedCheck for voltage to ground:There should be 5 V or more.Faulty driver's door switchShort to oroundo4LT GRN/REDPassenger's door openCheck for voltage to ground:There should be 1 V or less.Faulty passenger's door switchAn ooen inthewirePassenger's door closedCheck for voltage to groundlThere should be sVor more
. Faulty passenger's door switch. Short to oroundX5REDAVHTlgnition key inserted intothe ignition swhchCheck for voltage to ground:There should be 1 V or less.Poor ground {G401)Faulty ignition key switchAn ooen inthewirelgnition key removed fromrhe ionition switchCheck for voltage to ground:There should be 5 V or more.Faulty ignition key switchShort to oroundY1WHT/BLKDriver's door lock knobswitch unlockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G50'l)Faulty driver's door lock knob switchAn open in the wireDriver's door lock knobCheck for voltage to groundlIhere should be 5 V or more.Faulty driver's door lock knob switchShort to oroundY8YEUREDDriver's door lock knobswitch lockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G50'l)Faulty driver's door lock knob switchAn oncn inihewireDriver's door lock knobswitch unlockedCheck for voltage to ground:There should be 5Vor more' Faulty driver's door lock knob sw;tch. Shorr to oroundY10WHT/GRNDrtver's door lock switchunlockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G501iFaulty driver's door lock switchAn ooen in the wireDriver's door lock switch inCheck for voltage to ground:Therc shorl.l be 5V or m6rpFaulty driver's door lock switchShort to o rolrndY12WHT/BLUDriver's door lock switchlockedCheck for voltage to ground:There should be 'l V or less.Poor ground (G501)Faulty driver's door lock switchAn oDen in the wireDriver's door lock switch inCheck tor voltage to ground:There should be 5Vor moreFaulty driver's door lock switch
22-156
J

6. Disconnect the M, P, K and J connectors from the underdash fuse/relay box, and make these input tests at the connectors.
.lfanytestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem..lfalltheinputtestsproveOK,themultiplexcontrolunitmustbefaulty.Replacetheunder-dashfuse/relayboxassembly.
CavitvWireTest conditionTest: Desired resultPdsiblo c6use if result is not obtain€dK2BLU/ORNUnder all conditionsCheck for continuity betweenthe K2 terminal and the keylessreceiver unit 5P connectordisconnected:There should be continuitv.
An open in the wire
M7YEUBLKConnect J7 terminal to [,47lMgl terminal, and MglMTl terminalto J4
Check actuator operation:The driver's door lock actuatorshould lock lunlockl
Faulty driver's door lock actuatorAn open in the wireM9YEL
M6YEUBLKConnect J7 terminal to M6lMSl terminal, and M8lM6l terminalto J4
Check actuator operation:The passenger's door lockactuator should lock iunlockl
Faulty passenger's door lock actuatorAn open in the wireM8YEL
P16YELConnect J7 terminal to P17lP16l terminal, and P16lP17l terminalto J4
Check actuator operation:The hatch lock actuator shouldlock lunlockl
. Faulty hatch lock actuator. An open in the wireP17YEUBLK
-
22-157

Multiplex Control System
Component Location Index
IGNITION KEY LIGHTTest, page 22'91
lr, J
REAR CEILING LIGHTTest, page 22'96
LIGHT/SPOTLIGHTSTest, page 22-96
GAUGE ASSEMBLY
ECM
MULTIPLEX CONTROL UNIT{Built into the under-dashfus6/relav boxlTroubleshooting, page 22'172Input Test, page 22-175
22-168
t