Ignition switch HONDA CIVIC 2003 7.G Workshop 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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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)

ICircuit Diagram
' I'10.20 {a0AJ :usAib.a)l50A) :C.nd.IGNITiON SWITCH
/ BAI \--_to oJ- BLI,'YEL tcl ./
J
G201
HAICIILATCHSWITCH
{cont'd)
UiIDM HOOD IUSE/NEUY BOX
MULTIPLEXc0NT80rtNsPECTror!CONNECIOF
UNDEf, DASHFUSE/NEUYBOX
22-169

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
JI
/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
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.
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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.

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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CavitvWireTest conditionTest: Desired resultPossible cause if resuk is not obtainedX8WHT/BLKUnder allconditionsAttach to ground:The ignition keylight should come on.Blown No.3 (7.5A)fuse in the under,hood
Blown LEDAn ooen in the wireo7GRN/REDCeiling light switch inthe middle position,all doors closed
Attach to ground:The ceiling light,spotlights should come on.Elown No. 3 (7.54)fuse in the undeFhood
Faulty ceiling lightAn oDen in the wirec]1BLU Under all conditionsAttach to ground: Dash lights shouldBlown No. 2 (15Aifuse in the under-hoodfuse/relay boxFaulty taillight relayAn ooen in the wireF8GRN/REDBrake fluid reservoirfloat in downposition (brake fluid
Check for voltage to ground:There should be less than I V.Faulty brake fluid level switchAn open in the wire
Brake lluid reservoirfloat in up position(brake fluid at fulllevel)
Check for voltage to ground:There should be 5 V or more.Faulty brake fluid level switchShortto ground
E10YELUnder all conditionsCheck for voltage to ground:There should be battery voltage inthe sleep mode and 3 Tvoltswhen
. An open or short in the wire
K10WHT/GRNUnder all conditionsCheck for voltage to ground:There should be battery voltage inthe sleep mode and 3 Tvoltswhen
An open or short in the wire
22-177

sRs
Precautions and Procedures
General Precautions
Please read the following precautions carefully beforeperforming airbag system service. Observe theinstructions described in this manual. or the airbags
could accidentally deploy and cause damage or injuries.
. Except when performing electrical inspections.
always turn the ignition switch OFF, disconnect the
negative cable from the battery, and wait at least 3minutes before beginning work.
NOTE: The memory is not erased even if the ignition
switch is turned OFF or the battery cables are
disconnected from the battery.. Use replacement pans which are manufactured to the
same standards and quality as the original parts. Do
not install used SRS parts from another vehicle. Useonly new pans when making SRS repairs.. Carefully inspect any SRS part before you install it.
Do not install any part that shows signs of being
dropped or improperly handled, such as dents, cracks,
or deformation.
. Before removing any SRS parts (including the
disconnection of connectors), always disconnect the
SRS connector.. Use only a digital multimeter to check the system. lf itis not a Honda multimeter, make sure its outout is 10mA (0.01A) or less when switched to the lowest value
in the ohmmeter range. A tester with a higher output
could cause accidental deployment and possible
injury.. Do not put objects on the front passenger's airbag.. The original radio has a coded theft protection circuit.
Be sure to get the customer's radio code and write
down the frequencies for the radio's preset stations
before disconnecting the battery cable.. Before returning the vehicle to the customer, enter
the radio code. then enter the customer's radio
station presets, and set the clock. Do the engine
control module (ECM) idle learn procedure (see page
11-139).
23-14
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Steering-related Plecautions
Cable Reel Alignment
. Misalignment of the cable reel could cause an open in
the wiring, making the SRS system and the horns
inoperative. Center the cable reel whenever the
following is performed (see step 6 on page 23-121).
- Installation of the steering wheel- Installation of the cable reel- Installation ofthe steering column- Other steering-related adjustment or installation
. Do not disassemble the cable reel.
. Do not apply grease to the cable reel.
. lf the cable reel shows any signs of damage or
contamination. replace it with a new one. For
example, it does not rotate smoothly.

sRs
Precautions and Procedures {cont'dl
SRS Unit, Front lmpact Sensors, and Side
lmpact Sensors
. Be careful not to bump or impact the SRS unit, front
impact sensors, or side impact sensors whenever the
ignition switch is ON (ll), or for at least 3 minules after
the ignition switch is turned OFF.
. During installation orreplacement, be careful notto
bump (by impact wrench, hammer, etc.) the area
around the SRS unit, front impact sensors, and sjde
impact sensor. The airbags could accidentally deploy
and cause damage or injury.
After a collision in which any airbags or seat belt
tensioners were deployed. replace the SRS unit, front
impact sensors, and other related components (see
page 23-112). After a collision in which a side airbag
was deployed. replace the side impact sensor on the
deployed side and the SRS unit. After a collision in
which the airbags or the side airbags did not deploy,
inspect for any damage or any deformation on the
SRS unit, front impact sensors, and the side impact
sensors. lf there is any damage, replace the SRS unit
and/or the sensors.
23-16
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. Do not disassemble the SRS unit, front impact sensors,
or side impact sensors.
. Turn the ignition switch OFF, disconnect the battery
negative cable, and wait at least 3 minules before
beginning installation or replacement of the SBS unit,
or disconnecting the connectors from the SRS unit.
. Be sure the SRS unit, front impact sensors, and side
impact sensors are installed securely. with the
mounting bolts torqued to 9.8 N.m (1.0 kgf.m,7.2 lbf.ft)
. Do not spill wateroroil on the SRS unit, front impact
sensors, or the side impact sensors, and keep them
away from dust.
. Store the SRS unit, front imDact sensors and side
impact sensors in a cool (less than 104"F/40'C) and
dry (less than 80 % relative humidity, no moisture)
area.
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sRs
Precautions and Procedures (cont'dl
Disconnecting System Connectors
Before removing a front airbag. side airbag, or other SRS related devices {the SRS unit, the cable reel, the front impact
sensors, the side impact sensors, the seat belt buckle tensioners, and the seat belt tensioner connector), disconnectingconnectors from related devices, or removing the dashboard or the steering column, disconnect the airbag connectorsor the side airbag connectors to prevent accidental deploVment.
Turn the ignition switch OFF, disconnect the negative cable from the battery, and wait at least 3 minutes before
beginning the following procedures.'BeforedisconnectingSRSunitconnectorA(1)fromtheSRSunit,disconnectthedriver'sairbag4Pconnector(3).
the front passenger's airbag 4P connector (4), the driver's seat belt tensioner 2P connector (6), and the frontpassenger's seat belt tensioner 2P connector (7).
. Before disconnecting SRS unit connector B (8) from the SRS unit, disconnect both side airbag 2P connectors (11. '12),
and both seat belt buckle tensioner 4P connectors (9, 10).. Before disconnecting the cable reel 4P connector (2), disconnect the driver's airbag 4P connector (3).'Beforedisconnectingthefloorwireharness4Pconnector(5),disconnectbothseatbelttensioner2Pconnectors
(6.7).
23-20
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General Troubleshooting Information
DTC (Diagnostic Trouble Codesl
The self-diagnostic function of the SRS system allows it
to locate the causes of system problems and then store
this information in memory. For easier troubleshooting,
this data can be retrieved via a data link circuit.
. When you turn the ignition switch ON (ll), the SRS
indicator will come on. lf it goes off after 6 seconds,
the system is normal.. lf there is an abnormality, the svstem locates and
defines the problem, stores this information in
memory, and turns the SRS indicator on. The data
will remain in the memory even when the ignition
switch is turned off or if the battery is disconnected.. When you connect the Honda PG lM Tester to the 16P
data link connector (DLC)to short the SCS terminal,
and turn the ignition switch ON (ll). the SRS indicator
will indicate the diagnostic trouble code (DTC) by the
number of blinks.. When you connect the Honda PGM Tester to the 16P
data link Connector (DLC), you can retrieve the DTC in
the Honda Systems "SRS" menu.. After reading and recording the DTC, proceed with
the troubleshooting procedure for th is code.
Precautions. Use only a digital multimeter to check the system. lf
it's not a Honda multimeter, make sure its output is
10 mA (0.01A) or less when switched to the smallest
value in the ohmmeter range, A tester with a higher
output could damage the airbag circuit or cause
accidental airbag deployment and possible injury.. Whenever the ignition switch is ON (ll), or has been
turned OFF for less than 3 minutes, be careful not to
bump the SRS uniU the airbags could accidentally
deploy and cause damage or injuries.. Before you remove the SRS harness, disconnect the
driver's airbag connector. the front passenger's
airbag connector, both side airbag connectors, both
seat belt buckle tensioner connectors, and both seat
belt tensioner connectors.. Make sure the battery is sufficiently charged. lf the
battery is dead or low, measuring values won't be
correct.. Do not touch a tester probe to the terminals in the
SRS unit or harness connectors, and do not connect
the terminals with a jumper wire. Use only the
backprobe set and the Honda PGM Tester. Backprobe
spring loaded lock type connectors correctly.
Reading the DTC
When the SRS indicator is on, read the DTC using either
of the following methods:
PGM Tester "SRS" Menu Method:
Connect the Honda PGM Tester {A) to the 16P data link
connector {DLC)(B), and follow the Tester's Drompts in
the "SRS" menu.
lf the Tester indicates no DTC, no communication. DTC
3-6 to 3-'10, DTC 4-6 to 4-10, DTC 9-1, or DTC 9-2,
double-check by using the "SCS" menu method.
(cont'd)
23-23