2003 HONDA CIVIC heating system

Do the items in parts A, B, C, D, and E as required for mileage/time interval listed.
AReplace engine oillsee page 8-5i. Capacity without lilter change: 4.0 S (4.2 US qt, 3.5 lmp qt)Rotate tires. Follow the pattern shown in the Owner's Manual Checktire information and condition.
BReplace engine oil filter lsee page 8-6). Capacity with filter change: 4.20 (4.4 US qt, 3.7 lmp qt)Inspect front and rear brakes (see page 19 3i.. Check pads and djscs for wear (thickness), damage, and cracks.' Check calipers tor damage, leaks, and tjghtness ot mount bolts.Check parking brake adjustment. Should be Iully applied within 7 to I clicks.Inspect tie rod ends, steering gearbox, and boots {see page 17 5).. Check rack grease and steering linkage.. Check boots for damage and leaking grease. Chack fluid line {or damage and leaks.lnspect suspension components.. Chock bolts fo r tig htness.. Check condition of ball ioint boots lor deterioration and damage.Inspect driveshaft boots. Check boots for cracks and boot bands for tightness (see page 16-3).Insp€ct brake hoses and lines {including ABS). Checkthe mastercylinder, proponioning control valve, and ABS modulator{or damageand leakage.Check all fluid levels and condition ot tluids; check for leaks. lf necessary, add MTF lsee page 13'3), engioe coolant, brake fluid, and
Lwindshield washer fluid.lnspectexhaust system*. Check catalytic converter heatshield, exhaust pipe and mufflerfordamage,leaks, and tightness {soe page 9,8).lnspect {uel lines and connections*. Check for loose connections, cracks and deterioration; retighten loose connoctions and replacedamaged parts (s€e page 11 146).
InsDect and adiust drive belt.. Look for cracks and damage, and inspect auto tensioner (needs no adjustment).Replace the dust and pollen lilter (see page 21 39).. Replacethe dustand pollen filter whenever airf low lrom the heating and cooling system is lessthan normal.
Replace air cleaner element every 30,000 miles (48,000 km) (independent of time).
l
D
Ei I Replace brake fluid every 3 years (independent oI mileage).
According to state and federal regulations, failure to do the maintenance items marked with asterisk( * ) will not void customer's emissionswarranties. However, Honda recommends that all maintsnance service be done at the recommended interval to ensure long term reliability.
Y
3-5

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 Conditioning
A/C Service Tips and Precautions
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 systems.
Air conditioning refrigerant or lubricant vapor
can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.
The air conditioning system uses HFC-134a (R-134a)
ref rigerant and polyalkyleneglycol (PAG) ref rigerant oil,
which are not compatible with CFC'12 (R-12) refrigerant
and mineral oil. Do not use R-'12 refrigerant or mineral
oil in this system, and do not aftempt to use R 12
servicing equipment; damage to the air conditioning
system or your servicing equipment will result.
Use only service equipment that is U.L.-listed and is
certified to meet the requirements of SAE J2210 to
remove 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.
. Always disconnect the negative cable from the
battery whenever replacing air conditioning parts.
. Keep moisture and dirt out of the system. When
disconnecting any lines, plug or cap the fittings
immediately; don't remove the caps or plugs until
iust be{ore you reconnect each line.' Before connecting any hose or line, apply a few drops
of relrigerant oil to the O-ring.. When tightening or loosening a fitting, use a second
wrench to support the matching fitting.. When discharging the system, use a R-'134a
ref rigerant recovery/recycling/charging station; don't
release refrigerant into the atmosphere.
21-6
A: 130 m0 {4 l/3 tl.oz,4.6 lmp.oz)
],^
A/C Refrigerant Oll Replacement
Recommended PAG oil: KEIHIN SP 10:
. P/N 38897-P l3-A01AH: '120 m0 i4 fl oz). P/N 38899-P13'A01: 40 m0 i1 1/3 fl oz)
Add the recommended refrigerant oil in the amount
listed if you replace any of the following parts.
. To avoid contamination. do not return the oilto the
container once dispensed, and never mix it with other
refrigerant oils.. lmmediately af'ter using the oil, reinstallthe cap on
the container, and seal it to avoid moisture
aosorpron.. Donotspill the refrigerant oil on the vehicle; it may
damage the paint. lf it gets on the paint, wash it off
immediately.
Condenser ...........25 mA \516 tl.oz, 0.9 lmp.oz)
Evaporator ........... 45 m0 (1 113Il.oz, '1.4 lmp.oz)
Line or hose ......... '10 m0 {1/3 fl.oz,0.4 lmp.oz)
Receiver/Dryer .... '10 m0 ('113 fl.oz,0.4 lmp.oz)
Leakage repai r .... 25 m0, 1516 Il oz, 0.9 lmp.oz)
Compressor ......... For compressor replacemenl,
subtract the volume of oil drained
from the removed compressor from
130 m0 (4 1/3fl.oz, 4.6lmp.oz), and
drain the calculated volume of oil
f rom the new compressor: '130 m0
i.4113 fl.oz,4.6 lmp.oz) Volume of
removed compressor = Volume to
drain from new compressor.
NOTE: Even if no oil is drained from
the removed compressor, don't
d rain more than 50 m0 \1 2/3 fl.oz,'1.8 lmp oz)from the new
compressor.
\
REMOVEDCOMPBESSOR
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NEWCOMPRESSOR
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I I I DRAINING_*lH I voLUME

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

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
!

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 Gonditioning
a
\
Power Transistor Test
1. Disconnect the 4P connector from the power
Iranslslor.
2, Measure the resistance between the No. 1 and
No. 2 terminals of the power transistor. lt should be
about '1.4 1.5 kQ.
. lf the resistance iswithln the specifications, go to
step 3.. lf the resistance is notwithin the specifications,
replace the power transistor.
POWER TRANSISTOB
Carefully release the lock tab on the No. 4 terminal(BLUI/EL) (A) in the 4P connector, then remove the
terminal and insulate it from body ground.
(To 12 V power source on vehicle)
Reconnect the 4P connector to the power transistor.
Supply 12 volts to the No. 4 cavity with a jumper
wire.
Turn the ignition switch ON (ll), and check that the
blower motor runs.
. lf the blower motor does not run, replace the
power rranstsror.. lf the blower motor runs,the powertransistoris
oK.
12 V power source on vehicle)
21-38
1.
Heater Control Panel and Push
Switch Assembly Removal and
Installation
Remove the center panel (see page 20-62).
Remove the dials (A), then remove the self-tapping
screws and the heater control panel (B)from the
center panel (Cl. Remove the self-tapping screws
and the push switch assembly (D)from the center
panel.
lnstall the control panel and push switch assembly
in the reverse order of removal. After installation,
operate the control panel controls to see whether it
worKs propeny.
Run the self-diagnosis function to confirm that
there are no problems in the system (see page 21-
8).
3.
4.

Heating and Air Gonditioning
a
1.
Evaporator Core Replacement
Recover the refrigerant with a recovery/recycling/
charging station (see page 21-53).
Remove the bolt, then disconnect the suction line
(A) and the receiver line (B)from the evaporator
core.
6x10mm9.8 N.m (1.0 kgt.m, 7.2lbf.ft)
Remove the blower unit (see page 21-39).
Remove the self-tapping screws and the expansion
valve cover.
21-42
5. Carefully pull out the evaporator core without
bending the pipes.
Installthe core in the reverse order of removal, and
note these items.
. lfyou're installing a new evaporator core, add
refrigerant oil (KElHlN SP-]0) (see page 21-6).. Replace the O-rings with new ones at each fitting,
and apply a thin coat of refrigerant oil before
installing them. Be sure to use the correct O-rings
for HFC-134a (R-'134a) to avoid leakage.. lmmediatelyafter usingthe oil, reinstallthecap
on the container, and seal it to avoid moisture
absorotion.. Do not spill the refrigerant oil on the vehicle; it
may damage the paint. lf the refrigerant oil
contacts the paint, wash it off immediately.. Charge the system (see page 21-55).
6.