2003 HONDA CIVIC Indicator

Gauges
2.
3.
Gauge Assembly Replacement
1.Remove the instrument panel (see page 20-59),
then remove the upper column cover {see page 17-
Place a clean shop towel (A) under the gauge
assembly to prevent scratching the steering
colum n or dash panel.
Remove the screws from the gauge assembly (B).
Disconnect the connectors (C), and remove thegauge assemDry.
Installthe gauge assembly in the reverse order of
removal.
Coolant Temperature Gauge
Troubleshooting
Before testing, check the No. I { 10A) fuse in the under-
hood fuse/relay box and the No. '10 (7.5A) fuse in the
under dash fuse/relay box.
1. Start the engine, and check the malfunction
indicator lamp (MlL).
Does the MIL come on?
YES- Troubleshoot the cause of the ECM DTC (see
page 1 1-57), and recheck.
NO-Go to step 2.
2. Check for a multiplex control unit DTC (see page
22,168).
ls a DTC ind icated?
YES Troubleshooting the cause of the multiplex
control unit DTC {see page 22-168), and recheck.
NO Go to step 3.
3. Do the communication line check with the self-
diagnosis procedure (see page 22-56).
ls the word "Error" indicated on the odo/ttip
d isplay ?
YES The gauge cannot receive the signal from the
multiplex control unit and the ECI\,4. Check for an
open in the WHT/GRN wire (gauge connector
terminal B 13). lf no open is found, go to step 5.
NO Go to step 4.
4. Do the gauge drive circuit check with the self-
diagnosis procedure (see page 22-56).
Does the temperature gauge needle sweep lrom
the minimum position to the maximum, then tetutn
to the minimum position?
YES Go to step 5.
NO Replace the gauge assembly.l
5. Substitute a known-good ECM and recheck.
Did the symptom/ ind ication go away?
YES Replace the ECM.
NO Substitute a known good gauge assembly. lf
the symptom/indication goes away, replace thegauge assembly.l
4.
22-64

Exterior Lights
Component Location Index (cont'dl!
DAYTIME RUNNING LIGHTS RELAY {Canadal[Wire colors: RED, REDryEL, ILRED/BLK and RED/BLU ITest, page 22-51
_LOW BEAM CUTRELAY {Canadal _Wire colorsr REDMHT, RED/BLK, ILREDryEL and RED/BLU ITest, page 22-51
DASH LIGHTS BRIGHTNESSCONTROLLER
/
COMBINATION LIGHT SWITCHTesVReplacement, page 22-80
oAYTIME RUNNING LIGHTS CONTROL UNIT lcanada)Input Test, page 22-76
DRL INDICATOR LIGHT {Canadal
HIGH BEAM INDICATOR LIGHTBulb Replacement, page 22-63
UNDER.DASH FUSE/RELAY BOX
:' --,': - '
' i,-'-'l
..i \
I t- -
22-70

Exterior Lights
Daytime Running Lights Control Unit Input Test - Canada
The DRL indicator light in the gauge assembly will come on when you turn the ignition switch to ON (ll) with the
headlight switch off and the parking brake se1. lt should go off when you turn on the headlight switch and release the
parking brake. lf it comes on at any other time, do the control unit input test.
NOTE: When the daytime running lights are on, the high beam indicator will glow at half its normal intensity.
1. Remove the driver's dashboard lower cover (see page 20-60).
2, Disconnectthe l4Pconnector(A) from thedaytime running lightscontrol unit(B).
RED/BLUGNN/BLKRED/BLUGRN/BLKGRN/ORN
BLU/RED RED/YEL YEL/RED
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 4.
\
22-76

4. Make these input tests at the connector,
.lfanytestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem.
. lf all the input tests prove OK, the control unit must be faulty. Replace it.
CavityWireTest conditionTest: Desired resultPossible cause if result is not obtained2R E D/BLUUnder all
conditions
Check for voltage to ground:
There should be battery voltage.
Blown No. 14 (40A) fuse in the
under-hood fuse/relay box
Blown No. 3 {10A)fuse in the
under-dash fuse/relay box
An open in the wire12YE L/RE Dlgnition switch
oN (r)Check for voltage to ground:
There should be battery voltage.
Blown No. l2 (7.5A)fuse in the
under-dash fuse/relay box
An open in the wire
BLKUnder all
conditions
Check for continuity to ground:
There should be continuitv.
. Poor ground {G50'1). An oDen in the wire7BLKUnder all
conditions
Check for continuity to ground:
There should be continuitv.
. Poor ground (G501)
' An open in the wire
10REDI/ELCombination
light switch ON/ =f\
Check for voltage to ground:
There should be battery voltage.
Blown No. 15 (15A) fuse in the
under-hood fuse/relay box
Faulty headlight relay 2
Faulty combination light switch
An open in the wire
1RED/B LUCombination
light switch ON
{iD), and
dimmer switch
in HIGH
Connect a jumper wire between
No.3 and No. 1 terminals.
Both headlights (HIGH) and
h igh beam indicator light
should come on.
Blown bulb
Faulty low beam cut relay
Faulty combination light switch
Poor ground (G50'l )
An open in the wire'11
3
RED/BLK
GRN/BLK
Combination
light switch ON(iD), and
dimmer switch
in HIGH
Com bination
light switch ON(iD), and
dimmer switch
in HIGH
Connect a jumper wire between
No. 5 and No. 11 terminals.
Right headlight (HIGH) should
come on.
Check for continulty to ground
There should be continuity.
. Blown bulb. Faulty combination light switch. Poor ground (G 50'1 ). An open in the wire
. Faulty combination light switch. Poor grou nd {G501). An open in the wire
5
6GRN/ORNParking brake
lever oulled
Check for continuity to ground:
There should be continuitv.
Faulty parking brake switch
An open in the wire
8BLU/REDCombination
light switch OFF
Check for voltage to ground:
There should be battery voltage.
Faulty headlight relays
Short to ground
An ooen in the wire
WHT/BLUlgnition switch
oN 0r)
Attach to ground:
The DRL indicator light should
come on.
. Blown No. 10 (7.5A) fuse in the
under-dash fuse/relay box. Faulty DRL indicator. An ooen in the wire
t5G RN/REDlgnition switch
oN (||)Attach to ground:
The brake system light should
come on.
Faulty brake system indicator
An open in the wire
22-77

Turn Signal/Hazard Flasher
Component Location Index
COMBINATION LIGHT/TURN SIGNAL SWITCHTest, page 22-80Beplacement, page 22-80
TURN SIGNAL INDICATOR LIGHTS(ln the gauge assembly)Bulb Replacement, page 22'63
HAZARD WARNING SWITCHTest, page 22-88Replacement, page 22-88
TURN SIGNAL/HAZARD RELAYInput Test, page 22-87
UNDER.DASH FUSE/RELAY BOX
22-85

System Description
The vehicle is equipped with an immobilizer system that will disable the vehicle unless the proper ignition key is used.This system consists of a transponder located in the ignition key, an immobilizer control unit-receiver, an indicatorlight, and the ECM.
When the key is inserted in the ignition switch and turned to the ON {ll) position, the immobilizer control unit-receiversends power to the transponder in the ignition key. The transponder then sends a coded signal back to the immobilizer
control unit-receiver which then sends a coded signal to the ECI\4.
iEl'JUiliii'tlun"oona"|.r KEYCYLTNDER
lf the proper key has been used, the immobilizer indicator light will come on for about 2 seconds, then go off.lf the wrong key has been used or the code was not received or recognized by the unit, the indicator light will comeon for about 2 seconds, then it will blink until the ignition switch is turned OFF.lf the ignition switch is turned OFF, the indicator will blink for about 5 seconds to signal that the unit has reset
correctly, then the indicator will go off.
lf the customer has lost his key, and cannot start the engine, contact Honda Customer Relations.
IMMOBILIZER INDICATOR LIGHT BLINKING PATTERN:
IGNITION SWITCHON
OFF
PROPER KEYINSERTEDINDICATORLIGHTON
WRONG KEYINSERTEDINDICATORLIGHTON
OFF
(| i.,
IMMOBILIZER CONTROL UNIT.RECEIVER
)
22-163

)
I
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).
l
-_--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
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.