2003 HONDA CIVIC Control

DTC 14: An Open in the Evaporator
Temperature Sensor Circuit
1. Remove the evaporator temperature sensor (see
page 21-37).
2. Measure the resistance between the No. l and
No. 2 terminals of the evaporator temperature
sensor.x Dip the sensor in ice water, and measure
resistance. Then pour hot water on the sensor, and
check for change in resistance.
EVAPORA
RESISTANCEk0
TOR TEMPERATURE SENSOR
t-lll#l
ll,l,llI UT-TU I---r---T--
t^11c))-l\9/
50 6810 20
TEMPERATURE
ls the tesistance within the specifications shown
on the graph?
YES-Go to step 3.
NO Replace the evaporator temperature
sensor.I
3. Disconnect heater control panel connector B {22P).
86'F30 'c
Terminal side of male terminals
4. Check for continuity between the No. 7 terminal of
heater control panel connector B (22P) and the
No. 1 terminal of the evaporalor temperature
sensor 2P connector.
HEATER CONTROL PANEL CONNECTOR B {22P)Wire side of female terminals
EVAPORATOR TEMPERATURE SENSOR 2P CONNECTORWire side of female terminals
ls there continuity?
YES Go to step 5.
NO Repair open in the wire between the heater
control panel and the evaporator temperature
sensor.I
5. Disconnect heater control panel connector A (14P).
(cont'd)
21-23

Heating and Air Gonditioning
\
DTC Troubleshooting {cont'd)
6. Check for continuity between the No. 2 terminal of
heater control panel connector A (14P) and the
No, 2 terminal of the evaporalor temperature
sensor 2P connector.
HEATER CONTROL PANEL CONNECTOR A {14PIWire side of female terminals
LT GRN
EVAFORATOR TEMPERATURE SENSOR 2P CONNECTORWire side of female terminals
ls there continuity?
YES-Check for loose wires or Door connections at
heater control panel connector A ('l4P) and B l22Pl
and at the evaporator temperature sensor 2P
connector. lf the connections are good, substitute a
known-good heater control panel, and recheck. lf
the symptom/indication goes away, replace the
original heater control panel.l
NO Reoair ooen in the wire between the heater
control panel and the evaporator temperature
sensor.I
21-24
4.
DTC 15: A Short in the Evaporator
Temperature Sensor Circuit
1. Remove the evaporator temperature sensor (see
page 21-37).
2. Test the evaporator temperature sensor (see page
21-37 J.
ls the resistance within the specifications shown
on the graph?
YES Go to step 3.
NO Replace the evaporator temperature
sensor. !
Disconnect heater control panel connector B l22Pl.
Check for continuity between the No. 7 terminal of
heater control panel connector B {22P) and body
ground.
HEATER CONTROL PANEL CONNECTOR B (22P)
Wire side of female terminals
ls there continuity?
YES Repair short to body ground in the wire
betvveen the heater control panel and the
evaporator temperature sensor. I
NO-Substitute a known-good heater control panel,
and recheck. lf the symptom/indication goes away,
replace the original heater control panel.I

3.
Recirculation Control Motor Circuit Troubleshooting
1. Check the No. 14('10A)fuse inthe under-dashfuse/
relay box.
ls the f use OK?
YES Go to step 2.
NO- Replace the fuse, and recheck.l
2. Disconnect the recirculation control motor 5P
conneclor.
Turn the ignition switch ON (ll).
lvleasure the voltage between the No. 5 terminal of
the recirculation control motor 5P connector and
body ground.
RECIRCULATION CONTROL MOTOR5P CONNECTOR
7.
Wire side of female terminals
ls there battery voltage?
YES Go to step 5.
NO- Repair open in the wire between the No. 14
fuse in the under-dash fuse/relay box and the
recirculation control motor .l
Turn the ignition switch OFF.
Testthe recirculation control motor {see page 21-
36),
ls the recirculation control motor OK?
YES Go to step 7.
NO- Replace the recirculation control motor, or
repair the linkage and doors.I
Disconnect heater control panel connector A (14P).
5.
6.
8. Check for continuity between the No. 5 and No. 6
terminals of heater control panel connector A (14P)
and body ground individually.
HEATER CONTROL PANEL CONNECTOR A I14P)
Wire side of female terminals
ls there continuity?
YES Repair any shortto body ground in the
wire(s) between the heater control panel and the
recirculation control motor.l
NO-Go to step 9.
9. Turn the ignition switch ON (ll), and check the same
wires for voltage.
HEATER CONTROL PANEL CONNECTOR A Il4PI
Wire side of lemale terminals
ls therc any voltage?
YES Repair any shonto power in the wire(s)
between the heater control panel and the
recirculation control motor. This shon may also
damage the heater control panel. Repair the shon
to power before replacing the heater control
pa nel. I
NO-Go to step 10.
{cont d r
21-25

Heating and Air Conditioning
Recirculation Control Motor Circuit Troubleshooting (cont'd!
10. Turn the ignition swirch OFF.
11. Check for continuity between the following
terminals of heater control panel connector A ( 14P)
and the recirculation control motor 5P connector.'l4Pt 5P:
No.5 No. 1
No.6 No.2
HEATER CONTROL PANEL CONNECTOR A {14P}Wire side ol temale terminats
RECIRCULATION CONTROL MOTOR 5P CONNECTORWire side ol lemale terminals
ls there continuity?
YES Check for loose wires or poor connections at
heater control panel connector A ( 14P) and at the
recirculation control motor 5P conneclor. lf the
connections are good, substitute a known-good
heater control panel, and recheck. lf the symptom/
indication goes away, replace the original heater
control panel,I
NO Repair any open in the wire{s) between the
heater control panel and the recirculation control
motor.l
21-26

Heater Control Power and Ground Circuits Troubleshooting
1. Check the No.14 (10A)fuse in the under-dash
fuse/relay box.
ls the f use OK?
YES-Go to step 2.
NO-Replace the fuse, and recheck.l
2. Disconnect heater control panel connectorA{'14P).
3. Turn the ignition switch oN (ll).
4. Measure the voltage between the No. l4terminal
of heater control panel connector A (14P) and body
grouno.
HEATER CONTROL PANEL CONNECTOR A {14P}
23456
78I10 l,111214
Wire side of temale terminals
BLK/YEL
ls there battery voltage?
YES-Go to step 5.
NO Repair open in the wire betvveen the No. 14
fuse in the under-dash fuse/relay box and the
heater control panel.l
Turn the ignition switch OFF.
6. Check for continuity between the No. l3terminal of
heater control panel connector A (14P) and body
g rou nd.
HEATER CONTRoL PANEL CONNEcToR A (1ilP)
123456
I89r0 t,1l1214
BLK
.o
Wire side of temaleterminals
ls therc continuity?
YES Check for loose wires or poor connections at
healer control panel connector A (14P). lfthe
connections are good, substitute a known-good
heater control panel, and recheck. lf the symptom/
indication goes away, replace the original heater
control panel.l
NO Check for an open in the wire between the
heater control panel and body ground. lf the wire is
OK, check for poor ground at G501. I
21-27

Heating and Air Conditioning
Compressor Clutch Circuit
Troubleshooting (cont'dl
16. Check for continuity between the No. lterminal of
the compressor clutch relav 4P socket and the No. l
terminal of the compressor clutch 1P conneclor.
COMPRESSON CLUTCH RELAY 4P SOCKET
COMPRESSOR CLUTCH 1P CONNECTORTerminal side of male terminals
ls therc continuity?
YES-Check the compressor clutch clearance, the
thermal protector, and the compressor clutch field
coil (see page 21-48).I
NO-Repair open in the wire between the
compressor clutch relay and the compressor
clutch.l
21-32
A/C Pressure Switch Circuit
Troubleshooting
'1. Turn the ignition switch ON {ll).
2. Turn the blower switch on, and check for blower
motor operatron.
Does the blower motor run on all speeds?
YES Go to step 3.
NO Troubleshoot the blower motor circuit (see
page 21-20).
3. Turn the ignition switch OFF.
4. Disconnect heater control panel connectorA ('14P).
5. Turn the ignition switch ON (ll).
6. Measure the voltage between the No, 4 terminal of
heater control panel connector A {14P) and body
grou nd.
HEATER CONTROL PANEL CONNECTOR A (I4P}
1.
ls there battety voltage?
YES Go to step 7.
NO-Go to step 9.
Stan the engine.
Wire side of female termina's

8. Connect the No.4 terminal ofheatercontrol
connector A (14P) to body ground with a jumper
wire,
HEATER CONTROL PANEL CONNECTOR A I14P}
BLU
23456
78Ir0lx1112l3t4
JUMPER WIBE
Wire side of female terminals
Does the A/C system come on?
YES Replace the heater control panel.!
NO Refer to the multiplex control system (see
page 22-168).1
Using the Backprobe Set, connect the No. 9
terminal of under-dash fuse/relay box connector
F (12P) to body ground with a jumper wire.
UNOER.DASH FUSE/RELAY BOX CONNECTOR F {12P}
9.
25
61B g lrotll2
BLU/WHT
JUMPERWIRE
Wire side of female terminals
Does the NC system come on?
YES Go to step 10.
NO- Refer to the multiplex control system (see
page 22-168).1
NOTE: Check for multiplex codes in mode '1. Follow
the troubleshooting {or any codes found. lf no
codes are found, subsititute a known-9ood
multiplex control unit and a ECM one at a time.
Disconnect the Ay'C pressure switch 2P connector
and under-dash fuse/relay box connector F { 12P).
10.
'13.
21-33
11. Check for continuity between the No. 2 terminal of
the A,/C pressure switch 2P connector and the No. 9
terminal of under-dash fuse relav box connector
F t12Pt.
A/C PRESSURE SWITCH 2PCONNECTORWire side of female terminals
UNDER.OASH FUSE/RELAY BOX CONNECTOR F (12P)
Wire side of fenale lerrrinal'
ls there continuity?
YES Go to step 12.
NO Repair open in the wire between the
under-dash fuse/relay box and the A,,/C pressure
switch.I
Check for continuity between the No. 1 and No. 2
terminals of the A,/C pressure switch.
12.
A/C PRESSURE SWITCH
ls there continuity?
YES Repair open in the wire between the heater
control panel and the A,/C pressure switch.l
NO Go to step 13.
check for proper Ay'C system pressure.
ls the pressure within specitications?
YES Replace the AilC pressure switch.l
NO Repair the AilC pressure problem.I

Heating and Air Conditioning
Air Mix Control Motor Test
1. Disconnect the 5P connector from the air mix
control motor.
2. Connect battery powertothe No. l terminal ofthe
air mix control motor, and ground the No. 2
terminal; the air mix control motor should run, and
stop at Max Cool. lf it doesn't, reverse the
connections;the air mix control motor should run,
and stop at Max Hot. lf the air mix control motor
does not run, remove it. then check the air mix
control linkage and door for smooth movement.
. lf the linkage and door move smoothly, replace
the air mix control motor.. lf the linkage ordoorstickor bind, repairthem as
needed.. lf the air mix control motor runs smoothly, go to
step 3.
AIR MIX CONTROL MOTOR
3.
4.
Measure the resistance between the No. 4 and
No. 5 terminals. lt should be between 2.1 k to
3.9 kQ.
Reconnect the air mix control motor 5P connector,
then turn the ignition switch ON {ll).
Using the Backprobe Set, measure the voltage
between the No. 3 and No. 4 terminals.
Max Cool about 1V
Max Hot about 4 V
lf either the resistance or voltage readings are not
as specified, replace the air mix cotrol motor.
21-34
Air Mix Control Motor Replacement
1.Remove the under-dash fuse/relay box (see page
22-491.
Disconnect the 5P connector {A) from the air mix
control motor (B). Remove the self-tapping screws
and the air mix control motor from the heater unit.
Remove the rod (C) from the arm (D) of the air mix
controi motor.
Install the motor in the reverse order of removal.
After installation, make sure the motor runs
smoothly.
3.
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