indicator relay HONDA CIVIC 2003 7.G Owner's Manual

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Troubleshooting
Before troubleshooting the immobilizer system,
troubleshoot any EClvl Diagnostic Trouble Codes (DTCS)
(see page 11-3), and make sure the ECM has no
malfunction.
Note these items before trou bleshooting:
. Due to the action of the immobilizer system, the
engine takes slightly more time to start than on a
vehicle without an immobilizer system.. When the system is normal, and the proper key is
inserted, the indicator light comes on for 2 seconds,
then it will go off.. If the indicatorstartsto blink after 2 seconds, or if the
engine does not start. remove any other immobilizer
keys or large key fobs on the key ring, then repeat the
starting procedure.
lf the engine still does not start, continue with thisprocedure.
1. Turn the ignition switch ON {ll) with proper key.
2. Check to see if the immobilizer indicator light
comes on.
Does the indicator light blink?
YES Disconnect the 7P connector from the
immobilizer control unit-receiver, then go to step 9.
NO Check for these problems, then go to step 3.
. Blown No. 9 (10A)fuse in the under-hood
fuse/relay box.I. An open in the wire between the gauge assembly
and the immobilizer control unit-receiver.l. A faulty immobilizer indicator light,I. An open in the wire between the gauge assembly
and the under-hood fuse/relay box.l
Remove the driver's dashboard lower cover (see
page 20-59).
Remove the steering column lower cover (see page
11-9).
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-_--t
22-165
5. Disconnect the 7P connector (A)from the
immobilizer control unit-receiver (B),
Check for voltage between the immobilizer control
unit-receiver 7P connector No. 7 terminal and body
ground.
ls there battery voltage?
YES-Go to step 7.
NO Check for these problems;
. Blown No. 9 {10A)fuse in the under-hood fuse/
relay box.l. An open in the WHT/RED wire.l
Check for voltage between the immobilizer control
unit-receiver 7P connector No. 6 terminal and bodyground with the ignition switch ON {ll).
ls there battery voltage?
YES- Go to step 8.
NO Check for these problems:
. Blown No.6 (15A)fuse in the under-hood
fuse/relay box,I. Faulty PGM-Fl main relay 1,t. An open in the YEUBLK wire.l
1.
(cont'd)

ISystem Descriptions
The Multiplex Control System has four internal
functions:. Multiplexing (send multiple signals over sharedwtres). Wake up/sleep (runs at full power only on demand toreduce battery draw). Fail-safe (fixes or ignores faulty signals). Self-diagnosis (Mode 1 for the system, Mode 2 for
input lines)
The system controls the function of these circuits:. Entry lightcontrol (ignition key lightandceiting light). Wiper/washer intermittent wipe and park functions. Keyless/power door lock. Meter assembly, temperature gauge, and indicator
lights. HVAC (compressor and fan control). Key-in reminder. Headlight reminder. Seatbelt reminder
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/ar
22-171
Multiplex Communication
To reduce the number of wire harnesses, digital signals
are sent via shared multiplex communication linesrather than sending normal electrical signals throughindividual wires.. The input signals from each switch are converted todigital signals at the central processing unit (CpU).. The digital signalsaresentfromthetransmitting unitto the receiving unit as serial signals.. The transmitted signal is converted to a switch signalat the receiving unit, and it operates the related
component or monitors a swltch.. There are exclusive communicalion lines between
the ECM, the gauge assembly, and the under,dash
fuse/relay box.
Wake-up and Sleep
The multiplex control system has "wake-up" and"sleep" functions to decrease parasitic draw on the
battery when the ignition switch is OFF.. ln the sleep mode, the multiplex control unit stops
functioning (communication and CPU control) when it
is not necessary for the system to operate.. As soon as any operation is requested (for example, adoor is unlocked), the related control unit in the sleep
mode immediately wakes up and begins to function.. When the ignition switch is turned OFF, and the
driver's or front passenger's door is opened, then
closed, there is about a 10 second delay before the
control unit goes from the wake-up mode to the sleepmode.. lf any door is open, the sleep mode will not function.. lf a key is in the ignition switch, the sleep mode will
not function.. When in sleep mode, the draw is reduced from
70 80 mA to less than 10 mA.
Fail-safe
To prevent improper operation, the multiplex controlsystem has a fail-safe function. In the fail-safe mode,
the output signal js fixed when any part of the systemmalfunctions (for example a faulty control unit orcommunication line).
Each control unit has a hardware fail-safe function thatfixes the output signal when there is any CPUmalfunction, and a software fail-safe function thatignores the signal from the malfunctioning control unitand allows the system to operate normally.

Multiplex Control System
Multiplex Control Unit lnput Test (cont'd)
3. Inspect the connector and socket terminals to be sure they are all making good contact
.lftheterminalsarebent,looseorcorroded,repairthemasnecessary,andrecheckthesystem. llthe terminals look OK, go to step 4.
4. Reconnectthe connectorstothe under dash fuserelay box, and make surethese inputtests atthe appropriate connectors on lhe under-
dash fuse/relav box.
. lf any test indicates a problem, {ind and correct the cause, then recheck the system. lf allthe input tests prove OK, the multiplex control unit must be faulty. Replace the under_dash fuse/relay box assembly
CavitvWireTest conditionTest: Desired .esult r Possible cause if resullE qS!q!!e!!ed
J4BLK[J nder all conditionsCheck {or voltage 1o ground:Therc sholl.l he 1V or lessPoor ground (G20'l)An ooen in the wire
Y6BLKlJnder all conditionsCheck for voltage to ground:There should bc 1 V or less.Poor ground 1G501)An ooen in the wire
Y1BFNryELParking brake leverdown, turn theigntion switch ON (ll)
Check for voltage to ground:There should be battery voltagewhile the Brake system indicator ison forthe buld check.
An open in the wireShortto groundFaulty ABS modulatorcontrol unit
Check for voltage to ground:There should be 1V or less when the
J2WHT/REDUnder allconditionsCheck for voltage to groundiThere should be baftery voltage.Blown No.9 (10A)fuse in the under'hoodfuse/relay boxAn oncn in rhc wire
CavitvTest conditionTesi: Oesired resultPossible cause ifresult is notobtained
o3GRNDriver's door openCheck for voltage to ground:There should be 1 V or less-Faulty driver's door switchAn ooen in the wire
Driver's door closedCheck for voltage to ground:There should be 5 V or more.Faulty driver's door switchShort to qround
O4LT GRN/REDPassenger's doorCheck .for voltage 10 ground:There should be 1 V or less.Faulty passenger's door switchAn ooen inthewire
Passenger's doorCheck for voltage to ground:There should be 5 V or more.Faulty passenger's door switchShort to oround
osI]l.l
4.,
F1
F8
GRN/ORN
GRN/ORN
GRN/RED(USA)GRN/ORN(Canada)
Parking brake leverCheck for voltage to groLrnd:There shorl.l be 1 V or less.Faulty parking brake switch. An ooen in thewireCheck for voltage to ground:There should be 5 V or more.
. Faulty parking brake switchShortto ground
o5BLU/REDlgnition switch ON (ll),
driver's seat belt isCheck for voltage to ground:There should be 1V or less.Faulty driver's seat belt switchPoorground (G551)An oDen in the wire
Q6BLU/REDlgnition switch ON (ll)
driver's seat belt isbuckled.
Check {or voltage to ground:There should be 6 V or more.Faulty driver's seat belt switchShortto ground
P18RED
H",=
Check for voltage to ground:There sho0ld be 1V or less-
f -9*:li:'^:**:':s*:*
Faulty hatch latch swrtchPoor ground (G552)An open in the wireFaulty hatch latch switch
X5lgnirion key in the Check for voliage to gtound:ignit on switch Thpre should be I V or lcss
lgnrtron kev our o{ the Check for vollage to ground:
. Faulty ignition key switch. Poor ground (G401). An open in the wire
I : [11y.'::i':::1"' **6
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22-176

sRs
6.
SRS Indicator Circuit Troubleshooting (cont'dl
7.
Disconnect SRS unit connector C (8P) from the SRS
unit {see step 7 on page 23-22).
Disconnect gauge assembly connector A (22P).
Connect a voltmeter between the No, l4terminal of
gauge assembly connector A (22P) and body
ground. Turn the ignition switch ON (ll), and
measure voltage. There should be 0.5 V or less.
GAUGE ASSEMBLY CONNECTOR A {22P)
Wire side of female terminals
ls the voltage as specitied?
YES-Faulty SRS unit; replace the SRS unit (see
page 23-'l22l.a
NO-Short to power in the PNK wire of dashboard
wire harness A or in the floor wire harness; replace
the faulty harness.l
L Turn the ignition switch OFF. Check the No. 10
{7.5A)fuse in the under-dash fuse/relay box.
ls the tuse blown?
YES-Go to step 10.
NO Go to step 9.
23-106
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9. Connect a voltmeter between the No.2 terminal of
gauge assembly connector B (22P) and body
ground. Turn the ignition switch ON (ll), and
measure the voltage. There should be battery
voltaqe.
GAUGE ASSEMBLY CONNECTOR B (22P}
YEL
12345X68910
ll12,/ ,/,/x11o2122
Wire side of female terminals
ls therc battery voltage?
YES Faulty SRS indicator circuit in the gauge
assembly or poor contact at gauge assembly
connector B (22P) and the gauge assembly; if the
connection is OK, replace the gauge assembly.l
NO Open in the under-dash fuse/relay box No. 10
(7.5A) fuse circuit, or open in the YEL wire of
dashboard wire harness A. lf the under-dash fuse/
relay box is OK, replace lhe faulty harness.l
Replace the No. 10 (7.5A) fuse, then check to see if
the indicators comes on.
Do the indicators come on?
YES The system is OK at thls time.l
NO Repair the short to ground in the under-dash
fuse/relay box No. 10 (7.5A)fuse circuit.l
10.

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The SRS lndicator Stays On When ln "SCS"
Menu Method
NOTE:. lf you cannot retrieve DTCSwith the PGM Tester
using the SRS menu method. retrieve the flash codeswith the Tester in SCS mode {see page 23-24|,.. A new SRS unit must sense the entire system is OK
before completing its initial self-test. The most
common cause of an incomplete self-test is the
failure to replace all deployed parts after a collision,
in particular, seat belt tensioners and seat belt buckletenstoners.. An incomplete self-test prevents the PGM Tester fromretrieving DTCS, although flash codes are available in
the Tester's SCS mode.
1 . Erase the DTC memory using the MES connector(see page 23-26).
Does the SRS indicator go off while you are
erasing the DTC memory?
YES-Go to step 42.
NO Go to step 2.
Check the No. '13 { 10A) fuse in the under-dash
fuse/relay box.
lsthe f use OK?
YES--Go to step 19.
NO Go to step 3.
Replacethe No. 13 (10A) fuse.
Turn the ignition switch ON (ll), and wait for 30
seconds. Then turn the ignition switch OFF.
Check rhe No. 13 (10A) fuse.
ls the f use OK?
YES The system is OK at this time.I
NO Go to step 6.
3.
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6. Replace the No. 13 (10A) fuse.
7. Turn the ignition switch OFF. Disconnect the
battery negative cable, and wait for 3 minutes.
8. Disconnect the driver's airbag 4P connector (see
step 2 on page 23-21).
9. Disconnect the front passenger's airbag 4P
connector (see step 3 on page 23,21).
10. Disconnect both seat belt tensioner 2P connectors(see step 5 on page 23-221.
'11. DisconnectSRS unitconnectorA{18P)fromthe
SRS unit (see step 7 on page 23-22],.
'12. Reconnect the battery negative cable.
13. Turn the ignition switch ON (ll), and wait for 30
seconds. Then turn the ignition switch OFF.
14. Checkthe No. 13 ('10A) fuse.
ls the f use OK?
YES-Short to ground in the SRS unit; replace the
SRS unit (see page 23-122).a
NO Go to step 15.
15. Replace the No. 13 (10A) fuse.
{cont'd)
23-107

sRs
from the under-dash fuse/relav bor.
11.
18.
SRS Indicator Circuit Troubleshooting (cont'd)
'16. Disconnect dashboard wire harness B connector S
Turn the ignition switch ON {ll), and wait for 30
seconds. Then turn the ignition switch OFF,
Check the No. 13 (10A) fuse.
ls the f use OK?
YES Short to ground in dashboard wire harness
B; replace dashboard wire harness B.I
NO-Short to ground in the under-dash fuse/relay
box; replace the under-dash fuse/relay box.l
Turn the ignition switch OFF. Disconnect the
battery negative cable, and wait for 3 minutes.
Disconnect the driver's airbag 4P connector (see
step 2 on page 23-2'l).
Disconnect the front passenger's airbag 4P
connector (see step 3 on page 23-21).
Disconnect both seat belt tensioner 2P connectors
(see step 5 on page 23-22).
Disconnect SRS unit connector A (18P) from the
SRS unit (see step 7 on page 23-22).
19.
20.
21.
22.
23-108
24.Beconnect the battery negative cable.
Connect a voltmeter between the No. 3 terminal of
SRS unit connector A (18P) and body ground. Turn
the ignition switch ON (ll), and measure the voltage.
There should be baftery voltage.
SRS UNIT CONNECTOR A (18PI
Wire side of female terminals
ls there battery voltage?
YES Go to step 29.
NO Go to step 26.
Turn the ignition switch OFF.
Disconnect dashboard wire harness B connector S
26.
27.
PNK
from the under-dash fuse/relav box.

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28. Check resistance between the No. 3 terminal of
SRS unit connector A (18P) and the No. 2 terminal
of dashboard wire harness B connector S. There
should be 0 1.0 0.
DASHBOARD WIRE HARNESS B CONNECTOR S
Wire side offemale term
l2
rna lsPNK
a,
PNK T SRS uNrr
l23578I
101112l314151611l8
CONNECTOR A I18P)
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Wire side of female terminals
ls the rcsistance as specified?
YES-Open in the under-dash fuse/relay box orpoor contact at dashboard wire harness B
connectors; check the connection. lf the connection
is OK, replace the under-dash fuse/relay box.l
NO-Open in dashboard wire harness B; replace
dashboard wire harness B.I
Turn the ignition switch OFF.
Disconnect SRS unit connector C {8P) from the SRS
unit (see step 7 on page 23-22],.
29.
30.
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SRS UNIT CONNECTOR C I8P}
31. Connect the No. 3 terminal ofSRS unitconnectorA(18P) and the No. 5 terminal of SRS unit connector
C (8P)with a jumper wire.
PNK
JUMPERWIRE
PNK
Wire side of female terminals
SRS UNIT CONNECTOR A I18P)
Wire side of temale terminals
32. Turn the ignition switch ON (llf .
33. Check the SRS indicator.
Did the SRS indicator go off?
YES Faulty SRS unit; replace the SRS unit (see
page 23-122l.a
NO-Go to step 34.
34. Turn the ignition switch OFF.
35. Disconnect the jumper wire between the No. 3
terminal of SRS unit connector A (18P) and the
No. 5 terminal of SRS unit connector C (8P).
36. Check the No. 13 (10A)fuse in the under,dash
fuse/relay box.
ls the f use OK?
YES Go to step 40.
NO Go to step 37.
37. Replace the No. 13 {10A)fuse.
(cont'd)
23-109

Service Manual lndex
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NOTE: Referto the lollowing listto look up A/C Pressure Switch CircuitDTCS, symptoms, fuses, connectors, wire Troubleshooting ......... ...-.-....-...-.-.-....-..21-32 Bharnesses, specifications, maintenanceschedules, and general serviceinlormation:
DTC Troubleshooting Indexes
A/C Signal CircuitTroubleshooting.........................-...... 11-'133 Back-up Light SwitchTest .......................................................... 13'3A/F lAir Fuel Ratiol SensorABS/TCS Components ........................ 19-34 Replacement ....................................... 1 1-113 Back-up Li9ht3EPS Components ................................. '17-22 Circuit DiagramFueland Emissions11-i A-Dillar Corner Trim
ABS Indicator Circuit
Heating/Ventilation ................................ 21-9 Replacement ...............-.....-..............-.... 20,96 Ball Joint BootssRS ........................................................ 23-28Replacement ......
... 19-52 Ball Joints
22-75
18 16
Remova1.............-.......... . ...........18-10Symptom Troubleshooting Indexes TroubleshootingABS/TCSComponents........................ 19 35Cruise Control System ..........................4 38 ABS Modulator-contml UnitEPS Components ................................. 17-23 Bemoval/lnstallation ............................ 19-57 BettervFan Controls10,12
Accessory Powor Socket Front
Blowor Pow€r Transistor
.......22 50
Blower UnitRemoval/lnstallation ............................ 21-39
Fuel and Em issions .............................. 11-10 ABS/TCS ComoonentsHeating/Ventilation..............................21 10 Component Location Index ................. 19-30 Beverage Holder
SRS ........................................................ 23'30 CircuitDiaqram.......................... 19'42Blower MotorReplacement .....21 41
21-38
Power 0istribution ...............................22-46 TesVReplacement .............................. 22'149Under-dash Fuse/Relay Box ............... 22 45Under-hood Fuse/Belay Box ...............22 44 Accessory Power Sockets
Fuse/Relay lndexes
(to harness)
Connector and Wire Harness lndexesComponent Connectors
Circuit Oiagram .................................. 22-149
Air Cleaner......2214 Rep1acemen1.....................................11-162
Air MixControl MotorMeintenence section .................... Section 3 Replacement ......................................... 21'34 Brake CelipersTest......................21-34 Overhaul19-14,23Gene.al lnlormation section........ Section 1
21.57
Airbag. Driver's
Ahernator FR Signal CircuitTroubleshooting .... .........-..........11 134
AntennaReplacement
Inspection ............................................. 19-24Rep|acement................. .................... 19-25
Bieke Meder Cylinder
Irake Discs
A
Replacement ....................................... 23 1 'l3 Inspection .................... ................... 19-13,22Repair ...........-...................................... 23 1 16Brake Fluid Level SwitchAirbag. Front Passenger's TestBeplacement....................................... 23-1 14AIC Brake LightsComponent Location fndex ...................21-3 Altemator CircuitDiagram....................................22-74Description.....................................-....21'1'l Beplacement ................ ........................... 4 29CircuitDiagram....................................21-14 Overhaul .................................................4-30 Brake Lines and Hoses
19.10
A/C CompressolReplacement .......-...-............................. 21 -41
A/C Compr€ssor ClulchRep1acement......................................... 19-15.........22-103 Inspection ............................................. 19-16Inspecton........Overhaul ..........
A/C CondenserReplacement,.,
21-442l-49 Audio Unit
Replacement
Brake PadsRemoval/lnstallation .. ........................22-100 Inspection/Rep1acement................ 19-11,20A/C Compressor Clutch CircuitTroubleshooting ................................... 21-30 Audio Unit Connector Brake Pedal22101 Adjustment..............19,6ArfC Comoressor Relief ValvcReplacement ..........-...-.......................... 21-51 Audio/Entertainment
A/C Compr$sor Thermal Protector Circuit DiagramReplacement............-............................ 21-51
Component Location In dex .................22-9A Test .......-.............. 22-84Breke Pedal Posilion Switch
Brake Pedal Position Switch Signal Clrcuit11-137
.....21 52
A/C Condenser Fan CircuitTroubleshooting ................... . . . . . .....21-28
)s
Troubleshooting
(cont'd)