Body HONDA CIVIC 2003 7.G User Guide

'10. Check continuity between the ECM connector
terminal 810 and body ground.
ECM CONNECTOR S I24PI
23 t4 t567
8I10,/1,/315
118,Nnt,/2123
ACGL (WHT/BLUI
t1'
Wire side ol female terminals
ls there continuity?
YES- Repair short to ground in the wire between
the ECM and the engine wire harness 6P connector.
t
NO-Go to alternator and regulator test.
Alternator and Regulator Circuit Test
1. Be sure the battery is sufficiently charged and in
good condition {see page 22-50), and the
connections at the fuse box and alternator are
clean and tight.
2. Raise the hoist to full height.
3. Hook up the ammeter, 0 400 A, to the starter
sub harness.
Lower the hoist.
Hook up the voltmeter, 0 20 V (accurate within
0.1V),toT101.
(cont'd)
4-23

\
L
7, Check for continuity between ECM connector
terminal 818 and body ground.
ECM CONNECTOR B {24PI
123 t4 t561
8910,/1,/35
11ont,/2123
ACGC {WHT/GRN}
o
Wire side ot female terminals
9.
ls there continuity?
YES-Repair short to ground in the wire between
the alternator and the ECM.I
NO-Check that the terminals are firmly seated at
the ECM connector B. lf OK, substitute a known-
good ECM, and recheck (see page 11-6).
lf prescribed voltage is now available. replace the
original ECM,I
Turn the headlights and ignition switch OFF.
Disconnect ECM connector B (24P).
10. Check for continuity between ECM connector
terminal 818 and engine wire harness 6P connector
terminal No.2.
ACGC (WHT/GRN)
ECM CONNECTOR B l2,lPI
12314l5lll67
8910t.)15
11on2123
oC (WHT/GRN)
23
56
ENGINE WIRE HARNESS 6P CONNECTOR
Wire side oI lemale terminals
ls therc continuity?
YES Repair or replace the starter subharness or
the alternator (see page 4-30).I
NO Repair open in the wire between the
alternator and the ECM.I
4-25

Cooling System
Radiator and Fans Replacement
1. Drain the engine coolant (see page 10-6).
2. Remove the front bumper {see page 20,85).
3. Remove the bulkhead.
4. Remove the upper radiator hose and lower radiator hose.
DRAIN PLUG
UPPER BADIATOR HOSE
BAOIATOA FANASSEMBLY
{
O.RINGRADIATOR CAP
BADIATOB
LOWERCUSHION
\-
RADIATOR FANswtTcH24Nm{2.1t kgl m. 17lbl hl
LOWER FADIATORHOSE
RESERVETANK
A/C CONDENSERFAN ASSEMBLY
9.8 N m {1.0 kgf m,7.2 lbf ft)CONNECTORSRADIATOB FAN SWITCHCONNECTOB
5. Disconnect the fan motor connectors and radiator fan switch connector, then pull the radiator up and out.
6. Remove the fan shroud assemblies and other parts from the radiator.
7. Installthe radiator in the reverse order of removal. Make sure the upper and lower cushions are set securelV.
8. Install the bulkhead in the reverse order of removal. Apply body paint to the bulkhead mounting bolts.
9. Fill the radiator with engine coolant and bleed the air (see page 10-6).
10-10
\.

Fan Gontrols
Radiator Fan Circuit Troubleshooting
1. Check the No. 4 (20A) fuse in the under-hood
fuse/relay box, and the No. 14 (10A) fuse in the
under-dash fuse/relay box.
ls the tuse (s) OK?
YES-Go to step 2.
NO- Replace the fuse (s) and recheck.l
2. Remove the radiator fan relay from the under-hood
fuse/relay box, and test it (see page 22-51).
ls the relay OK?
YES Go to step 3.
NO Replace the radiator fan relay. t
3. Measure the voltage between the No. 2 terminal of
the radiator fan relay 4P socket and body ground.
RADIATOR FAN RELAY 4P SOCKET
Terminal side of female terminals
ls there battery voltage?
YES Go to step 4.
NO Replace the under-hood fuse/relay box. I
10-14
\-
(
4. Connect the No. landNo.2terminalsofthe
radiator fan relay 4P socket with a jumper wire.
RADIATOR FAN RELAY 4P SOCKET
JUMPERWIRE
Terminal side of Iemale terminals
Does the radiatot fan run?
YES Go to step 5.
NO Go to step 6.
Disconnect the jumper, and turn the ignition switch
ON { ll}. Check for voltage between the No. 3
terminal of the radiator fan relay 4P socket and
body ground.
BADIATOB FAN RELAY 4P SOCKET
Termlnal side of female terminals
ls there battety voltage?
YES-Go to step 9.
NO Check for an open in the wire between the
under-hood fuse/relay box and under-dash fuse/
relay box.l
\-

7.
Disconnect the radiator fan motor 2P connector.
Check for continuity between the No. 1 terminal of
the radiator fan relay 4P socket and the No. 2
terminal of the radiator fan motor 2P connector.
RAOIATOR FAN REI-AY 4P SOCKET
Terminal side offemale terminals
RADIATOR FAN MOTOR 2P CONNECTOR
ls thete continuity?
YES-Go to step 8.
NO Repair open in the wire between the under-
hood fuse/relay box and the radiator fan motor 2P
connector terminal No. 2,I
8. Check for continuity between the No, 1terminal of
the radiator fan motor 2P connector and bodv
g rou nd.
RADIATOR F
Wire side of female terminals
ls there continuity?
YES Replace the radiator fan motor.l
NO Check for an open in the wire between
radiator fan motor 2P connector terminal No. 1 and
body ground. lf the wire is OK, check for a poor
ground at G301.1
AN MOTOR 2P CONNECTOR
rftr
T-
Y
9.
10.
Reinstall the radiator fan relay.
Disconnect the radiator fan switch 2P connector.
Connect the No. 1 and No. 2 terminals, of the
radiator fan switch 2P connector with a jumper wire.
RAOIATOR FAN SWITCH2P CONNECTOR
11.
5\- IJUMPERf-; 'fl I wrRE
--
Wire side of female terminals
Does the radiator fan run?
YES- Replace the radiator fan switch.l
NO-Go to step 12.
Remove the jumper wire, and measure the voltage
between the No, 2 terminal of the radiator fan
switch connector and body ground,
RADIATOR FAN SWITCH2P CONNECTOR
ls there battery voltage?
YES Check for an open in the wire between
radiator fan switch 2P connector terminal No. 1 and
body ground. lf the wire is OK, check for a poor
ground at G301.1
NO Repair open in the wire between the radiator
fan switch terminal No. 2 and the under-hood
fuse/relay box.l
10-15

Fan Controls
Radiator Fan Switch Circuit
Troubleshooting (Openl
1. Disconnect the radiator fan switch 2P connector.
2. Turn the ignition switch ON (ll).
3. Measure voltage between the No.2 terminal ofthe
radiator fan switch 2P connector and body ground.
RADIATOR FAN SWITCH 2PCONNECTOR
ls there battety voltage?
YES-Go to step 4.
NO- Repair open in the wire between the radiator
fan switch 2P connector terminal No. 2 and under-
hood fuse/relay box.l
Turn the ignition switch OFF, and check for
continuity between the No. '1 terminal of the
radiator fan switch 2P connector and body ground.
RADIATOB FAN SWITCX 2PCONNECTOR
ls there continuity?
YES Replace the radiator fan switch. t
NO Check for an open in the wire between theradiator fan switch 2P connector terminal No. 1 and
body ground. lf the wire is OK, check for a poor
ground at G301.1
10-16
\-
Radiator Fan Switch Circuit
Troubleshooting (Short)
NOTE: After troubleshooting, perform the engine
control module (ECM)idle learn procedure (see page
1 1,139).
1. Remove the radiator fan relay from the under-hood
fuse/relay box, and test it (see page 22-51).
ls the relay OK?
YES Go to step 2.
NO Replace the radiator fan relay.I
2. Remove the radiator fan switch, and test it (see
page 10-17 ).
Is the radiatot tan switch OK?
4.
YES Go to step 3.
NO Replace the radiator fan switch.I
Disconnect the battery negative cable from the
battery.
Disconnect engine control module {ECM) connector
B (24P) and the under hood fuse relay box 14P
connector.
Check for continuity between the No. 2 terminal of
the radiator fan switch 2P connector and bodygrouno.
RADIATOR FAN SWITCH2P CONNECTOR
lstnere continuity?
YES Repair short in the wire between the radiator
fan switch 2P connector terminal No. 2 and under-
hood fuse/relay box.l
NO Replace the under-hood fuse/relay box.t
\I
\

Fuel and Emissions
Fuel and Emissions Systems
SpecialTools
General Troubleshooting
Information
DTC Troubleshooting lndex ....
Symptom Troubleshooting
1ndex...............
System Descriptions ................
Howto Set Readiness Codes ..
PGM-FlSystem
Component Location Index ....
DTC Troubleshooting ..............
MIL Circuit Troubleshooting ...
DLC Circuit Troubleshooting ..
Injector Replacement ...............
A,/F Sensor Replacement .........
Secondary HO2S
Replacement
ECT Sensor Reolacement .......
CMP Sensor B {TDC Sensor)
Replacement
IAT Sensor Replacement .........
Knock Sensor Replacement ....
CKP Sensor Reolacement .......
VTEC/VTC
Comoonent Location Index ....
DTC Troubleshooting ..............
VTC Oil Control Solenoid
Valve Removal/Test .............
CMP Sensor A Replacement ...
VTEC Solenoid Valve
Removal/lnsoection .............
ldle Control System
Component Location Index
DTC Troubleshooting ..............
A,/C Signal Circuit
TroubleshootinS ...................
Alternator FR Signal Circu it
TroubleshootinS ...................
EPS Signal Circuit
TroubleshootinS ...................
Brake Pedal Position Switch Signal
Circuit Troubleshooting .............
ldle Speed Inspection
ECM ldle learn Procedure .......
Fuel Supply System
Component Location Index
Fuel Pump Circuit Troubleshooting
1't-2
I I-J
11-7
1 1-10
11-12
11-46
11-49
11-52
11-97
11-109
11-111
11-113
11-113
11-114
11-114
11-115
11-115
11-116
11-117
1 1-1 18
11-127
11-128
11-128
11-129
1I-130
I t- t55
11-134
1 1- 135
1 1-137
1 1-138
1 1-139
1 1-140
11-141
11-144
Fuel PressureTest ................... 11-145
Fuel Lines Inspection ............... 11-146
Fuel Line/Ouick-Connect
Fittings Precautions ............. 1 1-148
Fuel Line/Ou ick-Con nect
Fittings Removal .................. 1 1-149
Fuel Line/Ou ick-Con nect
Fittings lnstallation ............... 11-150
Fuel Pressure Regu lator
Replacement ......................... 11-152
Fuel Fifter Replacement ........... 11-152
Fuel Pump/Fuel Gauge Sending
UnitReDlacement ................. 11-153
Fuel Pulsation Damoer
Rep1acement ......................... 11-154
Fuel Tank Reolacement ........... 11-155
Fuel GaugeSending UnitTest ....... 11-156
Low Fuel lndicatorTest ................. 1 1-158
Intake Air System
Comoonent Location Index .... 11-159
Throttle BodyTest ................... 11-160
Intake Air Bypass Control
Thermal Valve Test .............. 11-161
Air Cleaner Reolacement ........ 11-162
Air Cleaner Element
Reolacement ......................... 11-162
Throttle Cable Adjustment ...... 11-163
Th rottle Cable
Removal/lnstallation ............ 1 1-164
Th rottle Body Removal/
Installation .. 11-165
Th rottle Body Disassembly/
Reassemblv .......................... 11-166
Catalytic Converter System
DTC Troubleshooting .............. 1 1-167
PCV System
DTC Troubleshooting .............. 1 1-168
PCV Valve InsDection
and Test ...... 1 1- 169
PCV Valve Reolacement .......... 11-169
EVAP System
Component Location Index .... 11-170
DTCTroubleshooting .............. 11-171
EVAP Two Way Valve Test ...... 11-186
Fuel Tank Vaoor Control
Valve Test ... 11-187
EVAP Canister Replacement ... 11-189
Fuel Tank Vaoor Control
Valve Reolacement .............. 1 1-189Fuel Pressu re Relieving ...........

Fuel and Emissions Systems
Symptom Troubleshooting Index
When the vehicle has one of these symptoms, check the diagnostic trouble code (DTC) with the scan tool. lf there is no
DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.
SvmotomDiaqnostic procedureAlso check lor
Engine will not sta rt
(MlL works OK, no DTCS set)
1. Test the battery {see page 22-50).
2. Test the starter (see page 4-8).
3. Troubleshoot the fuel pump circult (see page 11
141).
Low compressron
No ignition spark
lntake air leaks
Locked up engine
Broken timing chain
Contaminated fuel
Engine will not start (MlL
comes on and stays on, or
never comes on at all, no
DTCS set)
Troubleshoot the l\4lL circuit (see page 1 '1-97).
Engine will not start
(immobilizer indicator stays
on or flashs)
Troubleshoot the immobilizer system (see page 22-165).
Hard starting(MlL works OK, no DTCS set)
1. Testthe battery (see page 22-50).
2. Checkthe fuel pressure (see page 11-145).
Low compression
Intake air leaks
Contaminated fuel
Cold fast idle too low(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure (see page 11-139).
2. Checkthe idle sDeed (see paqe 11-138).
Cold fast idle too high
(MlL works OK, no DTCS set)
Do the ECI\4 idle learn procedure (see page 1 1- 139).
Checkthe idle speed {see page 11-138).
Inspect/adjust the throttle cable (see page 1 '1-'163).
Inspect and test the throttle body {see page 1 1-160}.
']
2.
3.
ldle speed fluctuates
(MlL works OK, no DTCS set)
1. Dothe ECM idle learn procedure (see page 11-'139).
2. Check the idle speed (see page 11-138).
3, Inspecvadjust th e throttle cable (see page 11''163).
4. Insoect and test the throttle bodv (see paqe 11- 160)
Intake air leaks
After warming up, idle speed
is below specifications with
no load
{MlL works OK, no DTCS set)
1. Do the ECIVI idle learn procedure (see page 1 1- 139).
2. Troubleshootthe alternator FR signal circuit (see
page 11-'134).
3. InsDect and test the throttle bodv {see paqe 1 1-160).
Vacuum hose clogged/
cracked/poor
connectron
After warming up, idle speed
is above specifications with
no toao(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure {see page 1'j-139).
2. Troubleshoot the alternator FR signal circuit(see
page 11-134).
Low power
(MlL works OK, no DTCS set)
1. Check the fuel pressure(seepagell-145).
2. Inspect and test the th roftle body (see page 11-160).
3. Inspecvadjust the throttle cable (see page 11-'163).
Low compressron
Camshaft timing
problem
Engine oil levelprootem
Engine stalls(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure (see page 1'l'139).
2. Check the fuel pressure{seepagell-145).
3. Check the idle speed (see page I 1-138).
4. Troubleshootthe brake pedal position switch signal
circuit (see paqe 11-137).
lntake air leaks
Faulty harness and
sensor connections
\
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11-10
\-

Vacuum Hose Routing
I
O AIR FUEL RATIO IA/F) SENSOR {SENSOR 1}O SECONDARY HEATED OXYGEN SENSORISECONDARY HO2S} {SENSOR 2}
O MANIFOLD ABSOLUTE PRESSURE (MAPI SENSORO ENGINE COOLANT TEMPERATURE {ECT) SENSORO INTAKE AIR TEMPERATURE (IAT) SENSORO CRANKSHAFT POSITION (CKP) SENSORO KNOCK SENSORO CAMSHAFT POSITION (CMPI SENSOR BITOP DEAD CENTER ITDC) SENSOR)
O CAMSHAFT POSITION ICMPI SENSOR A@ IDLE AIR CONTROL (IACI VALVEO THRONLE BODY.O INJECTOR@ FUEL PULSATION OAMPER[I FUEL FILTER@ FUEL PRESSURE REGULATOR@ FUEL PUMP@ FUEL TANK
@ RESONATOR(9 AIR CLEANER@ POSITIVE CRANKCASE VENTILATION {PCVI VALVE@ THREE WAY CATALYTIC CONVERTER@ EVAPORATIVE EMISSION {EVAPI CANISTER@ EVAPORATIVE EMISSION {EVAP) CANISTERPURGE VALVE{} EVAPORATIVE EMISSION (EVAPI CANISTERVENT SHUT VALVE{' EVAPORATIVE EMISSION {EVAP) TWO WAY VALVE@ EVAPORATIVE EMISSION IEVAPI BYPASSSOLENOID VALVE@ FUEL TANK PRESSURE (FTP) SENSOR@ EVAPORATIVE EMISSION IEVAP} VALVE@ FUEL TANK VAPOR CONTROL VALVE60) FUEL TANK VAPOR RECIRCULATION VALVEO INTAKE AIR BYPASS CONTROL THERMAL VALVE
(cont'd)
11-25

Fuel and Emissions Systems
(
(
(
System Descriptions (cont'dl
Secondary Heated Oxygen Sensor (Secondary HO2S)
The secondary HO2S detects the oxygen content in the
exhaust gas downstream of the three way catalytic
converter (TWC) and sends signals to the ECM which
checks the efficiency of the TWC. To stabilize its output,
the sensor has an internal heater. The secondarv HO2S
is installed in the TWC.
ztRcoNtaELEMENTSENSORTERMINALS
HEATERTERMINALS
Starting Control
When the engine is started, the ECM provides a rich
mixture by increasing injector duration.
Throttle Position ITP) Sensor
The TP sensor is a potentiometer connected to the
throttle valve shaft. As the throttle position changes, the
sensor varies the signal voltage to the ECM. The TP
sensor is not replaceable apart from the throftle body.
ELEMENTBRUSH HOLDER
gRUSH
11-28
Vehicle Speed Sensor (VSS)
The VSS is driven by the differential. lt generates apulsed signal from an input of 5 volts. The number ofpulses per minute increases/decreases with the speed
of the vehicle.
BEARING