2003 HONDA CIVIC valve

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

Heating and Air Conditioning
Heater Valve Cable Adjustment
1. From underthe hood, open the cable clamp {A),
then disconnect the heater valve cable (B) from the
heater valve arm {C).
tFrom under the dash, disconnect the heater valve
cable housing from the cable clamp (A), and
disconnect the heater valve cable (B) from the air
mix control linkage {C).
, t.- l
\'r2t' ''' '
' ::"'
Set the temperature control dial on Max Cool with
the ignition switch ON (ll).
Attach the heater valve cable (B) to the air mix
control linkage (C) as shown above, then snap the
heater valve cable housing into the cable clamp (A).
.'.-:',,
-"ll
.....-
21-46
5, From under the hood, turn the heater valve arm {C)
to the fully closed position as shown, and hold it.
Attach the heater valve cable (B) to the heater valve
arm, and gently pull on the heater valve cable
housing to take up any slack, then install the heater
valve cable housing into the cable clamp (A).
.
\

Compressor Thermal Protector
Replacement
1. Remove the bolt, the ground terminal (A), and the
holder (B). Disconnect the field coil connector (C).
then remove the thermal protector (D).
Replace the thermal protector (A) with a new one,
and apply silicone sealant (B) to the bottom of the
thermal Drotector.
A
3. lnstall in the reverse order of removal.
7.4 N.m(0.75 kgf.m,5 rbf.ftl
Compressor Relief Valve
Replacement
2.
1.
4.
Recover the refrigerant with a recovery/recycling/
charging station (see page 21-53).
Remove the relief valve (A) and the O-ring (B). Plug
the opening to keep foreign mafter from entering
the system and the compressor oil from running
out.
A9,8 N.m(1.0 kgf m,7.2lbf.ft)
Clean the mating surfaces.
Install a new O-ring on the relief valve, and apply a
thin coat of refrigerant oil to the O-ring.
Remove the plug, and install and tighten the relief
valve.
Charge the system (see page 21-55).
21-51

Heating and Air Conditioning
Refrigerant Leak Test
Special Tool Required
Leak detector, Honda Tool and Equipment YGK-H-10PM
commerciallv available
Compressed air mixed with R-134a forms a
combustible vapor.
The vapor can burn or explode causing serious
injury.
Never use compressed air to pressure test
R-134a service equipment or vehicle air
conditioning system.
Air conditioning refrigerant or lubricant vapor
can irritate your eyes, nose, or throat.
Be carefulwhen connecting service equipment.
Do not breathe refrigerant or vapor
Use only service equipment that is U.L.-listed and is
certiified to meet the requirements of SAE J2210 to
remove HFC-134a (R-134a) from the air conditioning
system.
lf accidental system discharge occurs, ventilate the
work area before resuming service.
R-134a service equipment or vehicle air conditioning
systems should not be pressure tested or leak tested
with compressed air.
Additional health and safety information may be
obtained from the refrigerant and lubricant
manufacturers.
21-56
1. Connect a R-134a refrigerant recovery/recycling/
charging station (A) to the high-pressure serviceport (B) and the low-pressure service port (C), as
shown, following the equipment manufacturer's
anstructions.
Open the high pressure valve to charge the system
to the specified capacity, then close the supply
valve, and remove the charging system couplers.
Select the appropriate units of measure for your
refrigerant charging station.
Refrigerant capacity:
500 to 550 g
0.50 to 0.55 kg
1.10 to 1.21 lbs
17.6 to 19.4 oz
Check the system for leaks using a R-134a
refrigerant leak detector with an accuracy of 14 g(0.5 oz) per year or better.
lf you find leaks that require the system to be
opened (to repair or replace hoses, fittings, etc.),
recover the system.
After checking and repairing leaks, evacuate the
system.
3.

A/C System Tests
Pressure Test
Test resultssvmotom3DGaUSeDischarge (high)pressureabnormally high
After stopping compressor, pressure
drops quickly, and then continues toAir in systemRecover, evacuate (see page 21-54),and recharge with specified amount{see oaoe 21 55).
Beduced or no air flow throughcondenserClogged condenser or radiatorfinsCondenser or radiator fan not
CleanCheck fan voltage and rpm.Check fan direction.
Line to condenser is excessively hot.Restricted flow of refrigerant inReplace restricted lines.
Discharge pressureHigh and low pressures are balancedsoon after stopping compressor, Lowside is hioherthan normal.
. Faulty compressor dischargevalve. Faultv comoressor seal
Beplace the compressor.
Outlet of expansion valve is notfrosted, low pressure gauge indicatesFaulty expansion valveMoisture in system
. Replace the expansion valve.. Recover, evacuate for at least30 minutes, and recharge withsDecified amount.
Suction (low)pressureabnormally low
Expansion valve is not frosted, andlow-pressure line is not cold. Lowpressure gauge indicates vacuum,
' Frozen expansion valve(Moisture in system). Faulty expansion valve
Recover, evacuate for at least30 minutes, and recharge withspecified amount.Beplace the expansion valve.
Discharge temperature is low, and theair flow from vents is restricted.Frozen evaporatorRun the fan with compressor off, thencheck evaooratot temoerature sensor.
Exoansion valve is frosted.ean or reolace,
Receivetdryer outlet is cool, and inletis warm (should be warm duringooeralton),
Clogged receiver/dryerReplace receaver/dryer.
Suction pressureabnormally highLow pressure hose and check joint arecooler than the temperature aroundevaoorator,
Expansion valve open too longBepair or replace.
Suction pressure is lowered when..nrlenser is cooled bv water.Excessive refrigerant in systemRecover, evacuate, and recharge withqnp.ifie.lamo'rnr
High and low pressure are equalizedas soon asthecompressor is stopped,and both gauges fluctuate while
Faulty gasketFaulty high pressure valveForeign panicle stuck in high
Replace the compressor.
Suction anddaschargepressuresabnormallv hioh
Reduced air flow through condenser.. Clogged condenser or radiatorfins' Condenser or radiator fan notworkino orooerlv
CleanCheck voltage and fan rpm.Check fan direction.
Suction anddischarge pressureabnormally low
Low-pressure hose and metalendareas are coolerthan evaoorator,Clogged or kinked low-pressurehose oartsRepair or replace.
Temperature around expansion valveis too low compared with that aroundClogged high-pressure lineRepair or replace,
Fefrigerant leaks:omoressor clulch is dirtv.:omoressor shaft seal leakinqReolace the comDressor,
lomoressor bolt(s) are dirtv.no around bolt(s)Tiohten bolt{s) ot reolace comDressor,
;omDressor oasket is wet with oil.ietnoace the comoressor.
(cont'd)
21-57

Connectors and Harnesses
Engine Wire Harness
Camshaft position (CMP) sensorLllr sensorEC[,4 connector AECI/l connector BEngine coolant temperature (ECT)
sensorEngine oil pressure switchEVAP canister purge valveldle air control (lAC)valve
lgnition coil No. llgnition coil No. 2lgnition coil No. 3lgnition coil No. 4Iniector No. 1Inlector No.2Iniector No.3Iniector No. 4Intake air temperature {lAT) sensor
TDC sensorThrottle position (TP) sensorVehicle speed sensor (VSSI
VTC oil control solenoid valveVTEC oil pressure switchVTEC solenoid valvec 101
c102
233
242
Transmission housingLeft side of engineRight side ofengineUnder glove boxUnder glove boxLeft side of engine
Bight side oI engineLeft side of intake manifoldLeft side of intake manifoldMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine companment
28
1845672524201912
811102729303
22
12333332222233
322220
Left side of intake manifoldLeft side of engineLeft side of intake manifoldTransmission housingRight side o{ engineRight side of engineRight side of engineUnder right side of dash
Front of engine companment
Front of engine compartment
ECM wire harness {see page22-321Starter subharness (see page22-15)Starter subharness (see page22 151
Connector to Harness Index (cont'dl
22-16