2003 HONDA CIVIC heater core

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

Heating and Air Gonditioning
Component Location Index
SERVICE VALVE{LOW.PRESSUBE SIDEI
EVAPORATOR CORE(Built-in the heater unit)Beplacement, page 21 42
COMPRESSORBeplacement, page 21 47Clutch Check, page 21-48Clutch Overhaul, page 21-49Thermal Protector Check, page 21-48Thermal Protector Replacement, page 21 51Relief Valve Replacement, page 21 51
SERVICE VALVE{HIGH-PRESSURE SIDEI
RECEIVER/DRYER
CONOENSEBReplacement, page 21-52

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

Heater Unit/Core Replacement
SRS components are located in this area. Review the
SRS component locations (see page 23'13), and
precautions and procedures (see page 23-14) in the SRS
section before performing repairs or service.
1. Make sure you have the anti-theft code forthe radio,
then write down the freouencies for the radio's
Dreset buttons.
4.
Disconnect the negative cable from the battery,
Disconnect the suction and receiver lines from the
evaporator core (see page 21-42).
From under the hood, open the cable clamp (A),
then disconnect the heater valve cable (B) from the
heater valve arm (C). Turn the heater valve arm to
the fully opened position as shown
When the engine is cool, drain the engine coolant
from the radiator (see page 10-6).
6. Slide the hose clamps (A) back, the n d isconnect the
inlet heater hose (B) and the outlet heater hose (C)
from the heater core. Engine coolant will run out
when the hoses are disconnected; drain it into a
clean drip pan. Be sure not to let coolant spill on
the electrical parts or the painted surfaces. lf any
coolant spills, rinse it off immediately.
Remove the bolt and the heater valve, then remove
the mounting nut from the heater unit. Take care
not to damage or bend the fuel lines and the brake
lines, etc.
7.
8 x 1.25 mm12 N.m (1.2 kgf.m,8.7lbf.ft)
(cont'd)
21-43

Heating and Air Conditioning
Heater Unit/Core Replacement (cont'd)
8. Remove the dashboard {see page 20-66).
9. Disconnectthe connectors (A) from the blower
motor, the recirculation control motor, the mode
control motor, and the power transistor, then
remove the wire harness clips (B) and the
connector (C). Remove the self-tapping screws and
the bracket (D).
Disconnect the connectors (A) from the evaporator
temperature sensor and the air mix control motor,
then remove the wire harness clips (B) and the
connector (C). Remove the self-tapping screw and
the cover (D). Disconnect the heater valve cable (E).
10,
7t,
21-44
11. Remove the mounting bolts, the mounting nuts,
and the heater unit.
Remove the self-tapping screws and the expansion
valve cover (A). Carefully pull out the evaporator
core (B) so you don't bend the inlet and outlet pipes.
Remove the grommet (C), then remove the self-
tapping screws and the flange cover (D). Bemove
the self-tapping screws and the pipe cover (E), then
carefully pull out the heater core (F) so you don't
bend the inlet and outlet oioes.
@
5x 1.0 mm9.8 N.m11.0 kgl m,7.2 tbf.ftl
12.

13. Installthe heater core and the evaporator core in
the reverse order of removal.
14. Installthe heater unit in the reverse order of
removal, and note these items:
. Do not interchange the inlet and outlet heater
hoses, and installthe hose clamps securely.. Refillthe cooling system with engine coolant (see
page 10-6).. Adjust the heater valve cable (see page 2'l-461.. Make sure that there is no coolant leakage.. Make sure that there is no air leakage.. Refer to evaporator core replacement {see step 6
on page 21-42).. Do the engine control module (ECl\4) idle learn
procedure (see page 11-139).. Enter the anti-theft code for the radio, then enter
the customer's radio station Dresets.
21-45

)
Orive BehInspecaron................ 4-26
Door PanelsRemoval/lnstallation -............................. 20-4
Door Sash TrimRep1acement......................................... 20 10
Door StrikersAdiustment ........................................... 20-13
Door Weatherst psBeplacement...........-............................. 20 1 1
EPS Conirol UnitRemoval/1nsta11ation ..................-......... 17-67
EPS Indicator CircuitTroubleshooting ................................... 17 -47
EPS MotorRemoval/lnstallation .-.......................... 17-49
EVAP CanisterRep1acement......................... ......... 11,189
EVAP Control Syst€mComponentLocation Index ..............'11-170
EVAP Two-Wey ValveTest ..........-.............-............................ 11 186
Evaporetor CoreRep1acement........................ . ... 21-42
Evaporator Tomperature SensorReplacement......................................... 21 -37Test..................................... ..........2137
EvaporrtoFHeater UnitReplacement........................................ 21 43
Exhaust ManifoldRemoval/1nsta11ation ................................ I 7
Exhaust Pipe8ep|acement............................................. 9-8
Front SpeakersRep|acement....................................... 22-102
Front SuspensionComponentLocation Index................... 18-3
Fueland EmissionsDescription ........................................... 11-12
Fuel Fill DoorAdjustment ..........-................................ 20 93
Fuel Fill Door OpenetBeplacement........................ . ............ 20.109
Fuel Fill Door Opener CableReplacement....................................... 20- lO7
Fuel FilterReplacement....................................... 1 1-152
Fuel Gauge Sending UnitTest ......................-.-..........-.................. 11'156
Fuel Injection Syslem (PGM"FIlComponent Location 1ndex................. 11-49
Fuel IniectorsRep1acemen1....................................... 1 1 1 1 l
Fuel Lines and HosesInspection .......................................... 1 1'146Removal ....................... . .. . .... 11-149Insta|1ation .......................................... 1 1 150
FuelPipe ProtectolReplacement....................................... 20-104
Fuel Pressure RegulatotReplacement....................................... 1 1-152
Fuel Pulsation DamperReplacemenl................................... 11 154
Fuel PumpReplacement,,,,,.,.,.,,,.,,,,,,,,,,,,.,.,.,,,..,.. 11-153
Fuel Pump CircuitTroubleshooting -.......-....................... 1 1-141
FuelSupply SystemComponent Location lndex .............. 11 140Adjustment................................... 11-144Test........-...-................. ... ............- 11-145
FuelTankBeplacemenl.............. . ..... .. 11 155
Fuel Tank Vapor ControlValveTest ......................-....... ... . . 11-187Replacement,,.,,...,.,,,.,.,,,,... .. .. 11 189
Fuses{See first page ofthis Index)
)
Rep|acement................. ..................... 4 26
Drive Belt Auto-tensionellnspection ............................................... 4 21Rep1acement.................................... ..4-28
Driver's PocketRemoval/lnstallation -........................... 20-60
Driver's TrayRemoval/lnstallation .........................-.- 20-65
DRL {Daytime Running LightslControl Unitlnput Test .................... ........ . . . ......22-16
DTCs(See first page olthis Index)
Dust and Pollen FillerReplacement......................................... 21-39
Dynamic Damper, DriveshaftsReplacement........................................... 16-8
ECT SensorReplacement.,.,,,.,.,,,,,,,,,,,,,,................ 1 1-1 14
El€ctrical Power Steering IEPS)Signal CircuitTroubleshooting ........ ... .. 11-135
EmblemsReplacement......................-................ 20-100
Engine AssemblyRemova1 .................................................... 5 2Installation ............._.................................. 5-9
Engine Block AssemblyComponent Location Inder ..................... 7.3
Engine Block, BareInspect|onRepair
Fan ControlsComponent Location Index................. 10'l 1Circuit Diagram .. ..... . .. . .................. 10 13
Fender Fairing, FrontReplacement...-................................... 20-103
Final Driven Gear. M/TReplacement.... . . ................................ 13-53
FrameRepair Chan............ ... ....................... 20 11 4
Frame StiffenelReplacement......-................................ 20- J'13
Front ConsoleRemoval/lnstallation ............................ 20 5lDisassembJy/Reassemb|y ................... 20 58
Front DoorsComponent Location Index................... 20-2Adiustment ........................................... 20.12
Front Driveshaft AssemblyInspeclion .................... ... ....16 3Remova1...................-...... ... .....16-3Disassembly ............................... .....165Resassemb|y ................................-......... 16-9Insta11arion ........................ ...... ............ l6 17
Front lmpact SensorsRep1acement............................ ...23 125
................7-15................1 11
)
Entry Light Control SystemComponent Location Index ...............-. 22-89Circuit Dia9ram .................................... 22 90
EPS ComponentsComponent Location 1ndex..........-...... 17-!7Description ........................ ...... ..17-24Circuit Diagram11 26(cont'd)