2003 HONDA CIVIC o2 sensor

4. Check for continuity between the appropriate
wheel sensor (+) circuittermlnal and otherwheel
sensor (+) circuit terminals (see table).
DTCAppropiate
Terminal
Other Terminal
12No.5:
FRW (*i
No.7No.2No.9
'14No.7:
FLW IT.)
No.5No.2No.9
toNo.2;
RRW (T-)
No.5No.7No.9
18No.9:
RLW (*)No.5No. 7No.2
ls there continuity?
YES Repair short in the wires between the
appropriate wheel sensor and the other wheel
sensor harnesses.l
NO Clear the DTC, disconnect the Honda PGM
Tester, and test-drive the vehicle. lf the ABS
indicator comes on and the same DTC is indicated,
replace the ABS modulator-control unit.l
Disconnect the harness 2P connector from the
appropriate wheel sensor and check the resistance
between the (+) side and the (-) side ofthe wheel
sensor.
ls there less than 450 Q ?
YES Replace the wheel sensor.
NO- Repair short to wire between the appropriate
wheel sensor (+) and (-)circuits.l
DTC 21: Continuous Operation (Chipped
pulser)
1. Clear the DTC, then disconnect the Honda PGM
tesler.
2. Test-drive the vehicle at 19 mph (30 km/h) or more.
Doesthe ABS indicator come on and is DTC 21
ind icated?
YES Go to step 3.
NO The system is OK at this time.l
3. Check the pulser gear for a chipped tooth.
ls the pulser OK?
YES Check for a loose ABS control unit 31P
connector. lf necessary, substitute a known-good
ABS modulator-control unit, and recheck.l
NO Replace the driveshaft or hub unit (chipped
pulser gear).1
1g-47

Wheel Sensor Inspection
1.
2.
Inspect the front and rear pulsers for chipped or
damaged teeth.
Measure the air gap between the wheel sensor and
the pulser all the way around while rotating the
pulser. Remove the rear brake disc to measure the
gap on the rear wheel sensor. lf the gap exceeds
1.0 mm (0.04 in.), check for a bent suspension arm.
Standard:
Front; 0.4- 1.0 mm (0.02-0.04 in.)
Rear: 0.2 1.0 mm (0.01 0.04 in.l
Front:
0.4 '1.0 mm10.02 0.0'l in.l
I
t
Bear:
0.2 1.0 mm{0.01 0.04 in.}
Wheel Sensor Replacement
NOTE: Inslall the sensors carefully to avoid twisting the
wtres.
Front:
6 mm BOLT9.8 N.m{1.0 kgf.m,7.2lbf.ftl
6 mm BOLT9.8 N.m{1.0 kgf.m,7.2 lbf.ftl
Rear:
6 mm BOLT9.8 N.m11.0 kgf.m,7.2 lbf.ft)
WHEEL SENSOR
6 mm BOLT9.8 N.m(1.0 kgf'm,7.2 rbr.ft)
19-59

Front Seat Cover Replacement
For some models: SRS components are located in this
area. Review the SRS component locations (see page
23 13) and the precautions and procedures (see page
23-'14) in the SRS section before performing repairs or
service,
NOTE:. Take care not to tear the seams or damage the seat
covers,. On the passenger's seat with side airbag, do not
touch the OPDS sensor in the seat-back pad, and keep
it away from oil. Oil can corrode the sensor causing it
to fail.. Put on gloves to protect your hands.
Seat-back Cover
Remove the front seat isee page 20-71).
With side airbag: From under the seat cushion,
detach the side airbag connector clip (A), and on
the passenger's seat, detach the OPDS unit
connector clip (B). Release the hook springs (C)
from the seat cushion frame spring {D), then pull
the guide cover (E) back, and remove the wire ties
(F). The passenger's seat is shown, the driver's seat
is svmmetrical except it has no OPDS unit
connector.
'L
2.
3.Fold the seat-back forward.
Release the hooks (A), and unzip the seat-back
cover (B).4.
(cont'd)
20-75

21-2
z t-'5
z t-o
z t-o
21-8
21-9
21-10
21-11
21-14
z t- to
HVAC (Heating, Ventilation, and Air Gonditioningl
Heating and Air Conditioning
SpecialTools
Comoonent Location lndex ........
A/C Service Tios and
Precautions
A,/C Refrigerant Oil
ReDlacement
General Troubleshooting
lnformation
DTC Troubleshooting Index .......
Symptom Troubleshooting
1ndex..............
System Description .....................
Circuit Diagram
DTC Troubleshooting ..................
Recirculation Control Motor
CircuitTroubleshooting .......... 21-25
Heater Control Power and Ground
Circuits Troubleshooting ........ 21-27
Condenser Fan Circuit
Troubleshooting ...................... 21-28
Radiator and Condenser Fans
Common Circuit
Troubfeshooting ...................... 21-29
Compressor Clutch Circuit
Troubleshooting ...................... 21-30
A,/C Pressure Switch Circuit
Troubleshooting ...................... 21-32
Air Mix Control Motor
Test and Reolacement ............. 21-34
Mode Control Motor
Test and Replacement ............. 21-35
Recirculation Control Motor
Test and Reolacement ............. 21-36
Evaporator Temperature Sensor
Reolacement and Test ............. 21-31
Power Transistor Test ................. 21 -38
Heater Control Panel and
Push Switch Assemblv
Removal and Installation ........ 21-38
Dust and Pollen Filter
Reolacement ..21-39
Blower Unit Removal and
lnstallation ...... 21-39
Blower Unit Comoonents
ReDlacement ............................ 21-41
Evaporator Core
Reolacement ..21-42*Heater Unit/Core
ReDlacement ..21-43
Heater Valve Cable
Adjustment .....21-46
CompressorReplacement .......... 21-47
Comoressor Clutch Check .......... 21-48
Comoressor Clutch Overhaul ..... 21-49
Compressor Thermal Protector
Reo1acement ............................ 21-51
Comoressor Relief Valve
Reolacement ............................ 21-51
Condenser Reolacement ............ 21-52
Refrigerant Recovery .................. 21-53
System Evacuation ...................... 21-54
System CharginS ......................... 21-55
Refrigerant LeakTest .................. 21-56
A,/C Svstem Tests ........................ 21-57

HEATER UNIT/COREBeplacement, page 21-43
BLOWEN UNITRemoval and Installation, page 21-39
HEATER VALVE CABLEAdjustment, page 21-46
BLOWER UNIT COMPONENTSReplacement, page 21-41
DUSTAND POLLENFILTERReplacement, page 21'39
RECIRCULATION CONTROL MOTORTest, page 21-36Replacement, page 21-36
MODE CONTROL MOTORTest, page 21-35Replacement, page 21-35
AIR MIX CONTROL MOTORTest, page 21'34Replacement, page 21'34
POWER TRANSISTORTest, page 21-38
HEATER CONTROL PANELRemovaland Installation, page 21 38
PUSH SWITCH ASSEMBLYRemoval and Installation, page 21'38EVAPORATOR TEMPERATURESENSORReplacement, page 21-37Test, page 21-37
21-5

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

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