2003 HONDA CIVIC o2 sensor

- BU/YEL
-8lU/wH'I
EVAPORATOBTEMPERATUNESENSOR
sn 4-Lrenil
ffftH,, F*u,*
YEUBLU
YEL/NED
BED/YEI
RED/8LU
WHT/8LU
YEL/GRN
LTGRI'l
GNNMHT
GRN/YEL
8LK--..-...-l( coNNEcroFrir.Pt
f mxr{EcroB ! {2P)G5'1
8U
I
G602
m
::-:::: ., . a/c
M DEF
MODEl
Mq)EI
M00€2
M00t3
MOOE3
MOOEI
M00lco TnoLMOTOS
s
21-15

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

Heating and Air Conditioning
Radiator and Condenser Fans
Common
(cont'dl
Circuit Troubleshooting
9. Using a Backprobe Set, measure the voltage
between the No. 6 terminal of ECN4 connector B
{24P) and body ground with the ECM connectors
connecteo.
ECM CONNECTOR B {24P}
ls there battery voltage?
YES UDdate the ECM if it does not have the latest
so{tware, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
NO Repair open in the wire between the radiator
fan relay, the condenser fan relay and the ECM. t
Wire side of female terminals
21-30
Compressor Clutch Circuit
Troubleshooting
1. Check the No. 1 (20A) fuse in the under-hood
fuse/relay box, and the No. 14 {10A)fuse in the
under-dash fuse/relay box.
Are the tuses OK?
YES Go to step 2.
NO Replace the fuse(s), and recheck.I
2. Check the engine coolant temperature, the throttleposition sensor, and the idle speed (use the Honda
PGM Tester PGM-Fl data list if possible).
ls the coolant temperaturc above nomal, the
throttle position sensor rcading too high, or the
idle speed too low?
YES Troubleshoot and repair the cause of the
high engine coolant temperature, high throttle
position sensor reading, or low idle speed.l
NO-Go to step 3.
3. Remove the compressor clutch relay from the
under-hood fuse/relay box, and test it (see page 22-
51 ).
ls the relay OK?
YES Go to step 4.
NO Replace the compressor clutch relay.I
4. Measure the voltage between the No. 2 terminal of
the compressor clutch relay 4P socket and body
ground.
\
COMPfiESSON CLUTCH BELAY 'P SOCKET
ls there battery voltage?
YES Go to step 5.
NO Replace the under-hood fuse/relay box.I

Evaporator Temperature Sensor
Replacement
1.Remove the driver's dashboard lower cover (see
page 20-59) and the under cover (see page 20-60).
Remove the under-dash fuse/relay box (see page
22-491.
Disconnect the 2P connector (A) from the
evaporator temperature sensor (B), then remove
the connector clip (C). Remove the self-tapping
screw, and carefully pull out the evaporator
temperature.
4. Install the sensor in the reverse order of removal,
Evaporator Temperature Sensor
Test
l. Dip the sensor in ice water, and measure the
resistance between its terminals
EVAPORATOR TEMPERATURE SENSOR
2.
3.
Terminal side ol male terminals
Then pour hot water on the sensor, and check {or a
change in resistance.
Compare the resistance readings with the
specifications shown in the graph; the resistance
should be within the specifications
RESISTANCEk9
t0
32050 68 86 'F
10 20 30'c
TEMPERATURE
21-37

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.

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

Relay and Control Unit Locations
a
\
Dashboard (cont'd)
L
SRS UNIT
EPS CONTROL UNITPGM.FI MAIN RELAY 1lWire colors: YEUBLK,LWHT/BLK, WHT/BLK and RED/YEL
PGM.FI MAN RELAY 2fwire colors: YEUBLK, ILYEUGRN, YEUBLK and GRN/YEL I
AIR/FUEL RATIO SENSOR RELAY[Wire colorsr WHT, WHT/RED, IOBN and BLK/ORN I
22-10