2003 HONDA CIVIC Ignition switch

Brake System Indicator Gircuit Troubleshooting
Brake system indicator does not come on
'1. Discon nect the m ultiplex contro I unit l3Pconnector
and the ABS control unit 31P connector.
2. Check for continuity between the ABS control unit
3l P connector terminal No,21 and bodyground.
ABS CONTROL UNIT 31P CONNECTOR
Wire side of female terminals
ls there continuity?
YES Repair short to body ground in the wire
between the multiplex control unit and the ABS
control unit.l
NO Go to multiplex control system
trou bleshooting lsee page 22''172).a
Brake system indicator does not go off
1. Turn the ignition switch ON {ll).
2. Release the parking brake.
Does the brake system indicatot go ofl after
several seconds?
YES The system is OK at this time.l
NO Go to step 3.
3. Check the brake fluid level.
ls the level OK?
YES Go to step 4.
NO Refill the brake fluid, and recheck.l
4. Check the ABS indicator.
Does the ABS indicator stay on?
YES Read the ABS DTC (see step 1 on page 19-32).
and do the applicable troubleshooting for the DTC
NO Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the ABS control unit3lPconnector.
7. Connect the ABS control unit 31P connector
terminal No. 21 and body ground with a jumper
ABS CONTROL UNIT 31P CONNECTOR
(cont'd )
Wire srde of lemale lerminals
19-55

ABS Components
8.
9.
10.
11.
12.
13.
Brake System Indicator Gircuit Troubleshooting (cont'd)
Turn the ignititon switch ON (ll).
Check the brake system indicator.
Does the brake system indicatot go off?
YES-Replace the ABS modulator-control unit.l
NO-Go to step 10.
Turn the ignition switch OFF.
Connect the multiplex control unit 13P connector
terminal No. 'l and body ground with a jumper wire.
MULTIPLEX CONTROL UNIT 13P CONNECTOR
JUMPERWIRE
Wire side of female terminals
Turn the ignition switch ON (ll).
Check the brake system indicator.
Does the btake system indicatot go off?
YES Repair open in the wire between the
multiplex control unit and the ABS control unit.l
NO Go to multiplex control system
troubleshootin g (see page 22-17 2). a
19-56
\

ABS Modulator-Control Unit Removal and lnstallation
NOTE:. Donotspill brake fluid on the vehicle; it may damage the painU if brakefluidgetsonthepaint,washitoff
immediately with water.. Becareful not to damage or deform the brake lines during removal and installation.. To prevent the brake fluid from flowing, plug and cover the hose ends and joints with a shop towel orequivalent
malenal.
Removal
'1. Turn the ignition switch OFF.
2. Pull upthelock(A) oftheABScontrol unit3lPconnector(B),thendisconnecttheconnector.
FLARE NUTl5 N.m (1.5 kgt.m,11 lbt.ftl
6)o
CII mm NUT8.8 N.m {0.9 kgl m.6.5lbf ft)
6 mm BOLT9.8 N.m11.0 ksf.m,7.2lbf.ft)
\.
--/Q \,
\---'
(cont'd)
19-57

Heating and Air Conditioning
General Troubleshooting Information
How to Retrieve a DTC
The heater control panel has a self-diagnosis function. To run the self-diagnosis function, do the following:
1. Turn the fan switch OFF.
2. Pressand holdthe recirculation control switch andthe rear window defoooer switch down.
3. Turn the ignition switch oN {lli.
4. Release both switches. The recirculation indicator and the rear window defogger indicator come on. The
recirculation indicator goes off 3 seconds later and the Ay'C indicator comes on. then the self-diagnosis will begin.
About 10 seconds later, the self-diagnosis will finish and the A,/C indicator goes off.
.lfanytroubleisfound.therecirculationindicatorblinksthediagnostictroublecode(DTC)toindicateafaulty
circuil or comDonent.. lf the system is OK, the recirculation indicator stays off.
atc
@r
RECIRCULATIONCONTROL SWITCH
BECIRCULATIONINDICATOB
/A\
-:@
INOICATOR
REAR WINDOWOEFOGGER INDICATOR
REAR WINDOWDEFOGGER SWITCH
Examole of DTC indication Pattern IDTC 7)
DTC 7
Reseiting the Selt-diagnosis Function
Turn the ignition switch OFF to cancel the self-diagnosis function. After completing repair work, run the self-diagnosis
function aoain to make sure thatthere are no other malfunctions.
Recirculation +indicatot
Recirculation +indicalorgo6s oft----->
21-8

5. Turn the ignition switch ON (ll), and check the same
terminals for voltage.
HEATER CONTROL PANEL CONNECTOR A {14PI
HEATER CONTROL PANEL CONNECTOR B I22PI
Wire side of female terminals
ls there any voltage?
YES-Repair any short to power in the wire(s)
between the heater control panel and the air mix
control motor. This short may also damage the
heater control panel. Repair the short to power
before replacing the heater control panel.l
NO Substitute a known-good air mix control
motor, and recheck. lf the symptom/indication goes
away, replace the original air mix control motor. lf
the symptom/indication continues, substitute a
known-good heater control panel, and recheck. lf
the symptom/indication goes away, replace the
original heater control panel.I
Wire side of female terminals
DTC 9: A Problem in the Air Mix Control
Linkage, Door, or Motor
1, Test the air mix control motor (see page 21-34).
ls the air mix control motor OK?
YES-Substitute a known-good heater control
panel, and recheck. lf the symptom/indication goes
away, replace the original heater control panel.l
NO-Replace the air mix control motor, or repair
the linkage and door.l
21-17

Heating and Air Conditioning
DTC Troubleshooting.(cont'd)
DTC 10: An Open or Short in the Mode
Control Motor Circuit
1. Test the mode control motor (see page 21-35).
ls the mode cottol motor OK?
YES Go to step 2.
NO Replace the mode control motor.I
Disconnect the mode control motor 10P connector.
Disconnect heater control panel connectors A (14P)
and B \22P1.
Check for continuity between body ground and
heater control panel connector A (14P) terminals
No. 2, 10, and 11 individually, and between body
ground and heater control panel connector B (22P)
terminals No. '17, 18, 19, and 20 individually.
HEATER CONTROL PANEL CONNECTOR A {14PI
2.
3.
Wire side ol lemale terminals
ls there continuity?
YES Repair any shortto body ground in the
wire(s) between the heater control panel and the
mode control motor.l
NO Go to step 5.
HEATER CONTROL PANELCONNECTOR B {22P)
Wire side of femaLe lerminals
21-18
5. Turn the ignition switch ON (ll), and check the same
terminals for voltage.
HEATEB CONTROL PANEL CONNECTOR A {14P)
Wire side of female terminal
HEATER CONTROL PANEL CONNECTOR B {22PI
35X6
tl1215T61118t92A2122
RED/YELWHT
Wire side of female terminals
ls there any voltage?
YES-. Repair any short to power in the wire(s)
between the heater control panel and the mode
control motor. This short may also damage the
heater control panel. Repair the short to power
before replacing the heater control panel.l
NO- Go to step 6.

Turn the ignition switch OFF, and check for
continuity between the following terminals of
heater control panel connectors A (14P) and B (22P)
and the mode control motor 10P connector.
14P: 10P:
No. 2 No. '10
No. 10 No, 1
No. 11 No.2
22P: 10P:
No. 17 No.8
No. 18 No.6,9
No. 19 No.5
No. 20 No. 4,7
HEATER CONTROL PANEL CONNECTOR A (14PIWire side of lemale terminals
HEATER CONTROL PANEL CONNECTOR B {22PIWire side of female terminals
ls there continuity?
YES-Check for loose wires or poor connections at
heater control panel connectors A (14P) and B (22P),
and at the mode control motor 10P connector. lf the
connections are good, substitute a known-good
mode control motor, and recheck. lf the symptom/
indication goes away. replace the original mode
control motor.lf the symptom/indication continues,
substitute a known-good heater control panel, and
recheck. lf the symptom/indication goes away,
replace the original heater control panel.l
NO Repair any open in the wire(s) between the
heater control Danel and the mode control motor.l
MODE CONTROL MOTOR lOP CONNECTORWire side of female terminals
DTC 11: A Problem in the Mode Control
Linkage, Doors, or Motor
1. Testthe mode control motor (see page 21-35).
ls the mode control motor OK?
YES Substitute a known-good heater control
panel, and recheck. lf the symptom/indication goes
away, replace the original heater control panel.l
NO Replace the mode control motor, or repair the
linkage and doors.l
21-19

Heating and Air Gonditioning
DTC Troubleshooting {cont'd)
DTC 12: A Problem in the Blower Motor
Circuit
'1. Check the No. 12 (40A)fuse inthe under-hood
fuse/relay box, and the No. 14 (10A) fuse in the
under-dash f use/relay box.
Are the tuses OK?
YES-Go to step 2.
NO Replace the fuse(s), and recheck.l
2. Connect the No. 2 terminal of the blower motor 2P
connector to body ground with a jumper wire.
BLOWER MOTOB 2P CONNECTOR
JUMPER ] BLU/BLK
Wire side ol female terminals
3. Turn the ignition switch ON (ll).
Does the blowet motor run?
YES Go to step 4,
NO Go to step 17.
4. Turn the ignition switch OFF.
5. Disconnect the jumper wire.
6. Disconnect the power transistor 4P connector.
21-20
8.
7. Check for continuity between the No. 3 terminal of
the power transistor 4P connector and body ground.
POWER TRANSISTOR 4P CONNECTOR
Wire side ol temale terminals
ls there continuity?
YES-Go to step 8.
NO-Check for an open in the wire between the
power transistor and body ground. lf the wire is OK,
check for poor ground at G502.I
Connect the No. 1 and No. 3 terminals of the power
transistor 4P connector with a jumper wire.
POWER TRANSISTOR 4P CONNECTOR
Wire side of female terminals
Turn the ignition switch ON (ll).
Does the blower motor tun at high speed?
YES-Go to step 10.
NO-Repair open in the wire between the power
transistor and the blower motor.l
Turn the ignition switch OFF.
Disconnect lhe jumper wire.
9.
10.
11.
2
34
BLK
o