under-dash HONDA CIVIC 2003 7.G Repair Manual

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

Multiplex Control System
Troubleshooting
Mode 1 Tset
1. Remove the driver's dashboard lower cover {see
page 20-59).
2. Check the No. 9 ( 10A) fuse in the under-hood fuse/
relay box and the No. 10 (7.5A) fuse in the under-
dash fuse/relay box.
Are the fuses OK?
YES-Go to step 2.
NO-Find and repairthe cause ofthe blown fuse.!
3. Turn the ignition switch ON (ll).lf the driver's
seatbelt is unbuckled the seat belt reminder will
chime 6 times.
4. Set the ceiling light to the center position and close
allthe doors.
5. Connect the specialtoolto the multiplex inspection
conneclor.
6. After about 5 seconds the spotlight and ceiling light
should come on for 2 seconds, go out, then blink on
for 0.2 second to show the system is now in mode
1.
Did the spotlight and ceiling light indicate mode
1?
YES-Go to step 8.
NO Go to step 7.
22-172
-
7. Check for continuity between terminal 4ofthe
under-dash fuse/relay box connector J and body
ground.
ls there continuity?
YES Replace the under-dash fuse/relay box.l
NO - Repair the open in the wire.lf the wire is ok,
repair G301.1
8. lf ther are any DTCS present, the spotlight and
ceiling light will blink to indicate the DTC(S). lf more
than one DTC is present, the DTCS will be displayed
in ascending order, lf there are no DTCS the
spotlight and ceiling light will not blink again after
the mode 1 indication.
Are there any DTCg?
YES Go to step 9.
NO Go to the Mode 2 test.
9. Troubleshoot the DTC(S) in the order indicated
using the following charts.
lf a faulty control unit is suspected, substitute it
with a known food part and recheck for DTCS,
. lf the DTC(s) isstill present. go to the next step
listed for the DTC.. lf the DTC(S) is no longer present replace the
original part.

I
Individual
Multiplex
DTC
Probable Cause
The multiplex control unit cannot
receive signals from the gauge
assemDty.'lFaulty power or ground to thegauge assembly
2.Faulty gauge assemblv
3.Faulty under-dash f use/relay
box
The multiplex control unit cannot
receive signals from the ECM
1Faulty power or ground to the
ECM
2.Faulty ECM?Faulty under-dash fuse/relay
box
JInternal failure of the multiplex
control unit
1Faulty under-dash fuse/relay
box
5The gauge assembly cannot receive
signals from the multiplex control
unit and the ECM
Faulty power or ground to thegauge assembtv
Faulty qauge assemblv
6The ECM cannot receive signals
from multiplex control unit and thegauge assembty
1Faulty power or ground to the
ECM
Faulty ECM'
I
'Before replacing a Faulty ECM/PCM make sure ithas the latest software revision. UDdate if
necessary before swapping or replacing.
DTCs
Multiplex
DTC
Probable Cause
1,2 and 3
&
ECM DTC
P0600
Simultane
ously
Short to ground on one of the
communication wires.
Short to ground on the YEL wire
between the PCM terminal E24
and the under-dash fuse/relay
box terminal E10
2.Short to ground on the WHT/
GRN wire between the Gauge
assembly terminal A2 and
under-dash fuse/relay box
terminal K10
1and6
Simultane
ous ly
Open in the communication wire
IOpen in WHT/GRN wire
between the under-dash fuse/
relay box terminal K10 and the
Gauqe assemblV terminal 42
2and5
Simultane
ously
Open in the communication wire
1Open in the YEL wire between
the under-dash fuse/relay box
terminal E10 and ECM terminal
(cont'd)
22-173

IMultiplex Control Unit Input Test
Remove the driver's dashboard lower cover (see page 20-59).
Disconnect the under-dash fuse/relay box connectors C, E, F, J, K, O, p, O, X and y.
NOTE: All connectors are wire side of female terminals.
CONNECTOR C {14P}CONNECTOR E I13P)
1.
2.
CONNECTOR F {12P}
GRN/RED {USAIGRN/ORN (Canada)
coNNECTOR P (18P)
CONNECTOR J {8PI
WHT/RED
123
4561
BLK
{cont'd)
GRN/ORN BLU
CONNECTOR K {17P)
I
CONNECTOR O I12P)
CONNECTOR X {8P)CONNECTOR O (8P}
LT GRN/RED GRN/ORN
CONNECTOR Y {13P)
BRN/YEL
BLU/REDBLU/RED
345
67E10 )./12
YELGRN/RED
12457
810/V,/ l,/
WHT/GBN
3567I
,/1,/l,/121517
REDGRN/RED
WHT/BLK
RED/WHT
23,/1,/
618r012
BLK
22-175

I
g]
3
1 1. Check resistance between the No. 2 terminal of the
floor wire harness 3P connector and body ground.
There should be an open circuit. or at least 1 fvl Q ,
FLOOR WIRE HARNESS 3P CONNECTOR
Wire side ot temale terminals
ls the resistance as specified?
YES-Go to step 12.
NO Short to ground in the floor wire harness or
multiplex control unit. Replace the faulty harness or
part.I
Check resistance between the No. 3 terminal of the
floor wire harness 3P connector and body ground.
There should be an open circuit, or at least 1 M Q.
FLOOR WIRE HARNESS 3P CONNECTOR
LT GRN
Wire side of female terminals
ls the resistance as specified?
YES Go to step 13.
NO-Short to ground in the floor wire
replace the floor wire harness.I
12.
13. Check resistance between the No. 8 terminal of
SRS unit connector C (8P) and the No. 3 terminal of
the floor wire harness 3P connector. There should
be0 1Q.
FLOORWIRE HARNESS SRS UNITCONNECTORC I8P}3P CONNECTOB
Wire side of female terminals
ls the resistance as specitied?
YES Go to step 14.
NO Open in the floor wire harness; replace the
floor wire harness.l
Check resistance between the No. 4 terminal of
SRS unit connector C (8P) and the No. 2 terminal of
the floor wire harness 3P connector. There should
be0-1 0.
14.
FLOOR WIRE HARNESS3P CONNECTORSRS UNIT CONNECTOR C IsPI
Wire side of female terminals
ls the resistance as specified?
YES Replace the SRS unit (see page 23-122).1
NO Open in the floor wire harness or multiplex
control unit, or poor connection at the floor wire
harness, the under-dash fuse/relay box, and the
multiplex control unit. Check the connection at the
floor wire harness, the under-dash fuse/relay box,
and the multiplex control unit. lf the connection is
OK, replace the faulty harness or part.l
harness;
23-73