HONDA CIVIC 2003 7.G Workshop Manual

DTC Troubleshooting Index
In case of multiple problems, the recirculation indicator will indicate only the DTC with the least number of blinks.
ln case of an intermittent failure, the heater control panel will store the DTC until the ignition is turned off.
DTC {Recirculation
Indication Blinks)
Detection ltemPage
7An open in the air mix control motor circuit(see paqe 21-16)
8A short ln the air mix control motor circuit(see Daoe 21-'16)
9A problem in the air mix control linkaqe, door, or motor(see paqe 21- 17)
10An open or shon in the mode control motor circuit(see oaqe 21-18)
11A problem in the mode control linkage, doors, or motor(see paqe 21191
12A problem in the blower motor circuit(see paqe 21-20)
13A problem in the EEPROM in the heater control panel;
the control oanel must be reolaced
(see page 21-38)
14An ooen in the evaDorator temDerature sensor circuit(see paqe 21-23)
A short in the evaDoralor temoerature sensor circuit(see oaqe 21-241
21-9

Heating and Air Conditioning
{
a
a
SvmptomDiagnostic procedureAlso check for
Recirculation control doors do not
change between Fresh and Recirculate
Recirculation Control Motor
Circuit Troubleshooting (see page
21 251
Cleanliness and tightness of all
connectors
Both heater and Ay'C do not workHeater Control Power and Ground
Circuits Troubleshooting (see
page 21-27)
Blown fuse No. '14 (10A) in the
under-dash fuse/relay box
Poor ground at G501
Cleanliness and tightness of all
conneclors
Condenser fan does not run at all (but
radiator fan runs with the Ay'C on)
Condenser Fan Circuit
Troubleshooting {see page 21-28)
. Poor ground at G301. Cleanliness and tightness of all
connectors
Both fans do not run with the A,/C onRadiator and Condenser Fans
Common Circuit Troubleshooting
(see page 21-29)
Blown fuse No. 1 (20A) and No.4
(20A) in the under-hood fuse/relay
box
Poor ground at G30l
Cleanliness and tightness of all
connectors
Compressor clutch does not engage(both fans run with A,/C on)
Compressor Clutch Circuit
Troubleshootinq (see Daqe 21-30)
Cleanliness and tightness of all
connectors
A/C system does not come on (both
fans and compressor)
Ay'C Pressure Switch Circuit
Troubleshooting (see page 21-32)
Blown fuse No. 1 (20A) and No. 4
(20A) in the under-hood fuse/relay
box
Poor ground at G301
Cleanliness and tightness of all
connectors
\Symptom Troubleshooting Index
\
21-10
!

System Description
Heater Control Panel Inputs and Outputs
CONNECTOR A {r/rP)
CONNECTOR
CONNECTOR
HEATER CONTFOL PANEL CONNECIORS
CONNECTOR B (22P)
W re s de oitema eterm nals
Cavity Wire color_| \ln YAIR MIX POTENTIAL +5V
Sional
OUTPUT2LT GRNSENSOR COMMON GROUNDINPUT3PNK/BLUAIR MIX HOTOUTPUTBLUA,/C PRESSURE SWITCHINPUT5GRNA/ELRECIRCULATEINPUT6GRNA/VHTFRESHINPUT7BLUI/ELPOWER TRANSISTOROUTPUT8BLU/REDBLOWER FEEDBACKINPUTIGRNAIR MIX COOLOUTPUT10YEL/REDMODE DEFOUTPUT11. YEVBTU
YEL/BLK
MODE VENT
REAR WINDOW DEFOGGER RELAY
OUTPUT
INPUTBLKGROUNDOUTPUT14B LK/YELlG2 (Power)INPUT
Bon
CavityWire colorSiqnal1--T
2
3BLIVREDREAR WINDOW DEFOGGER SWITCH LEDINPUT
4LT GRNA./C SWITCH LEDINPUT
5LT GRN/BLKRECIRCULATION CONTROL SWITCH LEDINPUT
6PNVBLKAIR MIX POTENTIALOUTPUT
7BRNEVAPORATOR TEIMPERATURE SENSOROUTPUT
8
9
10
GAUGE ASSEMBLYal' 'TDr ri11RED
RED/BLKTAILLIGHTS RELAYINPUT
14BLUREAR WINDOW DEFOGGER SWITCHINPUTicLT GRN/REDA/C SWITCHINPUT16YEVREDRECIRCULATION CONTROL SWITCHINPUT17YEUGRNMODE 4OUTPUT18WHT/BLUMODE 3OUTPUT19RED/BLUMODE 2OUTPUT20RED/YELMODE 1OUTPUTBRN^,^/HTIGN (PowedOUTPUT22R E DA/r'HT(Not used)
(cont'd)
21-11

Heating and Air Gonditioning
System Description (cont'dl
The air conditioning system removes heat from the passenger compartment by circulating refrigerant through the
system as shown below.
/
BLOWER FAN
\
\,u
EXPANSION VALVE(Meters the requiredamount of refrigerantinto the evaporator)
A/C PRESSURE SWITCHWhen the refriqerant is below196 kPa (2.0 kgi/cm',28 psi)or above 3,140 kPa (32 kgf/cm'455 psi), the Py'c pressureswitch opens the circuit tothe Py'C switch and stops theair conditioning to protect thecompressor-
RECEIVER/DRYER(Traps debris, andremoves morsturel
APOBATOR TEMPERATURESENSOR
THERMAL PROTECTOR(Opens the compressor clutch circuitwhen the compressot temperaturebecomes too high)
RELIEF VALVE(Relieves pressure at the compressorwhen the pressure is too high)
A/C COMPRESSOR(Suction and comoression)\-^
I HrcH PRESSURE vAPoR
[ '.... -:--l Low PREsSUBE LrourD
tffi Low PREssURE vAPoR
This vehicle uses HFC-134a (R-'134a) refrigerant which does not contain ch lorofluorocarbons. Pay attention to the
following service items:
. Do not mix refrigerants CFC-12 (R-12) and HFC-134a (R-134a). They are notcompatible.. Use onlythe recommended polyalkyleneglycol (PAG ) refrigera nt oil (KElHlN SP '!0) designedfortheR-134a
compressor. Intermixing the recommended (PAG) refrigerant oil with any other retrigerant oil will result in
compressor failu re.. AllAy'C system parts (compressor, discharge line, suction line, evaporator, condenser, receiver/dryer. expansion
valve, O-rings for joints) have to be designed for refrigerant R 134a. Do not exchange with R-'12 parts.
. Use a halogen gas leak detector designed for refrigerant R-134a.. R-12 and R-134a refrigerant servicing equipment are not interchangeable. Use only a recovery/recycling/charging
station that is U.L.-listed and is certified to meet the requirements of SAE J2210 to service R-134a air conditioning
system.. Always recover the refrigerant R-134a with an approved recovery/recycling/charging station before disconnecting
any Ay'C fifting.
/-
CONDENSER(Radiation of heat)
21-12

Heating and Air Conditioning
Gircuit Diagram
UNDEN rcODFUSVRELIYSOXUNOER DASNfUSE/8EIlYBOX|GNUION SWTCfilG2 HoI ii 0l\l llll
+. C}F BLK/RED rG2 /
II
I
I
In.G301
A/C PnESSUEtswTOt
t...iCF
RADIATOS
oT0n
NADIATOS) tAl'// swtlcllj 19S"F 193"C) l
CONDEN$N
MOTOB
I8u(
I
IBLX
I
G301
l
;
/ .I IHEFMAI
Y PBorEcro8
lTl *n*,*,| _l
MUITIPLD(CONTFOIUNITI
-!10. irgF 8Ll
TT
BLU
I ilntho undor dasi luse/lelay box
21-14

- BU/YEL
-8lU/wH'I
EVAPORATOBTEMPERATUNESENSOR
sn 4-Lrenil
ffftH,, F*u,*
YEUBLU
YEL/NED
BED/YEI
RED/8LU
WHT/8LU
YEL/GRN
LTGRI'l
GNNMHT
GRN/YEL
8LK--..-...-l( coNNEcroFrir.Pt
f mxr{EcroB ! {2P)G5'1
8U
I
G602
m
::-:::: ., . a/c
M DEF
MODEl
Mq)EI
M00€2
M00t3
MOOE3
MOOEI
M00lco TnoLMOTOS
s
21-15

Heating and Air Conditioning
DTC Troubleshooting
DTC 7: An Open in the Air Mix Control Motor
Circuit
1. Test the air mix control motor {see page 2'l-341.
ls the air mix control motor OK?
YES-Go to step 2.
NO-Replace the air mix control motor.l
2. Disconnect the air mix control motor 5P connector.
3. Disconnect heater control panel connectors A {14P)
and B (22P).
4. Check for continuity between the following
terminals of heater control panel connectors A
(14P) and B (22P) and the air mix control motor 5P
connector,
14P: 5P:
No. 1 No.5
No.2 No.4
No.3 No.2
No.9 No. 1
22P: 5P:
No.6 No.3
Wire side ol lem.letehi.6ls
ls there continuity?
YES-Check for loose wires or poor connections at
heater control oanel connectors A (14P) and B (22P)
and at the air mix control motor 5P connector. lf the
connections are good. 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.l
NO Repair any open inthewire(s) ketweenthe
heater control panel and the air mix control
motor.l
21-16
DTC 8: A Short in the Air Mix Control Motor
Circuit
1. Test the air mix control motor(see page 21-341.
ls the ait mix control motor OK?
YES-Go to step 2.
NO-Replace the air mix contorol motor.I
2. Disconnect the air mix control motor 5P connector.
3. Disconnect heater control panel connectors A (14P)
and B (22P).
4. Check for continuity between body ground and
heater control panel connector A (14P) terminals
No. 1, 2, 3, and 9 individually, and between body
ground and heater control panel connector B (22P)
terminal No. 6.
HEATERCONTROL PANEL CONNECTOR A {I4PI
HEATER CONTFOL PANELCONNECTOR B I22P1
ls therc continuity?
YES-Repair any shortto body ground ln the
wire(s) between the heater control panel and the air
mix control motor.l
NO-Go to step 5.
Wire side of female terminals
Wire side oilema e lerminals

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