2003 HONDA CIVIC idle air

ldle Gontrol System
Component Location Index
TE'
IDLE AIR CONTROL {IAC) VALVETroubleshooting, page 1 1-'131
11-129

ldle Control System
DTC Troubleshooting
DTC P0505: ldle Control System Malfunction
NOTE: lf DTC P1519 is stored atthe same time as DTC
P0505, troubleshoot DTC P1519 first, then recheck for
DTC P0505.
1. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle,
2. Checkthe engine speed at idle with no,load
conditions: headlights, blower fan, rear defogger,
radiator fan, and air conditioner off.
Is the engine running at 750t50 rpm?
YES - Intermittent failure, system is OK at this
trme.I
NO lf the idle speed is less than 700 rpm, go to
step 3; if it's 800 rpm or higher, go to step 4.
3. Disconnect the idle air control {lAC) valve3P
connector.
Does the engine speed increase or fluctuate?
YES- Check the idle speed {see page 1 1-138). lf the
idle will not adjust properly, clean the passage in
the throttle body, and then adjust the idle. I
NO- Replace the IAC valve.I
4. Turn the ignition switch OFF.
5. Remove the intake air duct from the throttle body.
6. Start the engine, and let it idle.
11-130
(
7. Put your fingers on the lower pon (A) inthethrottle
oooy.
Does the engine stall?
YES Checkthe idle speed (see page 11-138). lfit's
out of specification, replace the IAC valve.l
NO With the throttle valve completely closed,
check for vacuum leaks, and repair as necessary.l

ldle Gontrol System
't.
Alternator FR Signal Circuit Troubleshooting
Disconnect the alternator 4P connector from the
alternalor.
Turn the ignition switch ON {ll).
Measure voltage between ECM connector
terminals 424 and 813.
ECM CONNECTORS
2.
3.
A l31Pl
1 21345611 | 1.,'I
1011112,/56,/r8119l2C21
2312428129130
L(BRN/YEL)
ALTF(WHT
213 4t561
89ltal,/l/15
Wire side of female terminals
ls there about 5 V?
YES Go to step 4.
NO-Go to step 13.
4. Turn the ignition switch OFF.
5. Reconnect the alternator 4P connector.
6. Slan the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle.
7. lvleasure voltage between ECM connector
terminals A24 and B 13.
Does the voltage decrease when the headlights
and rear window defogger arc tutned on?
YES The alternator FR signal is OK.l
NO-Go to step 8.
8. Turn the ignition switch OFF.
9. Disconnect ECM connector B (24P).
10. Disconnect the alternator 4P connector.
/REDI
11-134
'11. Connect alternator 4P con necto r term inal No.4 to
body ground with a jumper wire.
ALTERNATOR 4P CONNECTOR
12
ALTF34IWHT/RED)
JUMPER WIRE
12.
Wire side of female terminals
Check for continuity between body ground and
EClvl connector terminal 813.
ECM CONNECTOB B (24PI
Wire side of female terminals
ls there continuity?
YES-Testthe alternator (see page 4-22).1
NO Repair open in the wire between the ECM(B 13) and the alternator.l
Turn the ignition switch OFF.
Disconnect ECM connector B (24P).
\
13.
't 4.

ldle Control System
ldle Speed lnspection
NOTE:' Leave the idle air control (lAC) valve connecled.. Before checking the idle speed, check these items:- The malfunction indicator lamp (MlL) has not been
reported on.- lgnition timing- Spark plugs- Air cleaner- PCV system. Pullthe parking brake lever up. Start the engine, and
make sure the headlights are off.
1. Disconnect the evaporative emission (EVAP)
canister purge valve 2P connector.
2. Connect a tachometer (A)to the test tachometer
connector (B), or connect the Honda PGM Tester (C)
or an OBD ll scan tool to the data link connector(DLC) (D) located under the driver's side of the
dashboard.
11-138
4.
3.
5.
6.
Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle.
Check the idle speed with no-load conditions;
headlights, blower fan, radiator fan, and air
conditioner off.
ldle speed should be: 750 t 50 rpm
Let the engine idle for 1 minute with the heater fan
switch on Hl and air conditioner on, then check the
idle speed.
ldle speed should be: 750 t 50 rpm
NOTE: lf the idle speed is not wilhin specification,
go to the Symptom Troubleshooting Index,
Reconnect the EVAP canister purge valve 2P
connector.

Intake Air System
Throttle Cable Removal/lnstallation
1. Fully open the throttle valve, then remove the
throttle cable (A) from the throttle link (B).
Remove the cable housing (C)from the cable
bracket (D).
Remove the throttle cable (A)from the accelerator
pedal (B).
2.
3.
SILICONE GREASE B(P/N 08798-9002)
(P/N 08?98-9002)
11-164
5.
Install in the reverse order of removal.
After installing, start the engine. Hold the engine at
3,000 rpm with no load (in neutral) untilthe radiator
fan comes on, then let it idle.
Hold the cable, removing all slack from it.
Set the locknut on the cable bracket {A).Turn the adjusting nut (B) so that its free play is
0 mm.
The should beno crearance.
Remove the cable from the cable bracket (A). Set
the adjusting nut on the other side of the throttle
bracket, then tighten the locknut {C}.
With the cable properly adjusted, check the throttle
valve to be sure it opens fully when you push the
accelerator pedal to the floor. Also check the
throttle valve to be sure it returns to the idle
position whenever you release the accelerator
Deoat.
7.
!
8.
9.
('1.0 kgf.m,7.2 tbf.ftl

Throttle Body Removal/lnstallation
NOTE:' Do not adjust the throttle stop screw.. Afterreassembly,adjustthethrottlecable{seepagell-163) and the cruise control cable (see page 4-45).. The throttle position (TP) sensor is not removable.
THROTTLELEVER
There should beno clearance
THROTTLE CABLE
MANIFOLDABSOLUTE PRESSURE{MAP} SENSOR
22Nm(2.2 kgt.m, 16 lbf.ft)
EVAPORATIVE EMISSION {EVAPICANISTER PURGE VALVE
IDLE AIR CONTROL{IACI VALVE
11-165

PCV System
DTC Troubleshooting
DTC P1505: PCV Air Leakage
1. Reset the ECM (see page 11-4).
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on
3. Let the engine idle tor al least 40 seconds with the
throttle fully closed.
4. Check for a DTC P1505 with the scan tool
ls DTC P1505 indicated?
YES-Check these parts for vacuum leaks l
. PCV valve. PCV hose. EVAP canister purge valve
. Throttle body. Brake booster hose
NO - Intermittent failure, system is OK at this
time.l
11-168

28.
29.
ls thete continuity?
YES-Go to step 28.
NO-Replace the EVAP canister vent shut valve (A)
and o-ring (B).1
Disconnect ECM connector E (31P).
Check for continuity between EVAP canister vent
solenoid valve 2P connector terminal No. 2 and
body ground.
EVAP CANISTER VENT SHUTVALVE 2P CONNECTOR
Wire side o{ female terminals
ls there continuity?
YES-Repair short in the wire between the EVAP
canister vent shut valve and the ECM (E21).1
NO Update the ECM if it does not have the latest
soflware, 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
30.
Vacuum Hoses and Connections Test
Do the fuel tank vapor control valve test (see page
1 1-187).
ls the fuel tank vapot control valve OK?
YES-Go to step 31.
NO Replace the fueltank vapor control valve.l
Tighten the fuel cap 3 "clicks", then monitorthe
FTP sensor readings with the Honda PGM Tester.
Start the engine. and let it idle for 5 minutes.
Check the FTP sensor readings.
ls the reading above 0.5 kpa (4 mm Hg, 0.16 in.
Hg) pressure, or about 3 V?
YES Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck {see page 1 1-6). lf the symptom/indication
goes away with a known-good ECfvl, replace the
original ECM.t
NO Check the following parts for leaks:l
. Fueltank (A)
. Fuel fill cap (B)
. Fuel fill pipe (C)
. Fueltank vapor control valve(D). Fueltank vapor recirculation valve (E)
. Fueltank vapor recirculation tube (F)
. Fueltank vapor signaltube (G)
. Fueltank vapor control venttube(H). FTP sensor (J)
- Repair or replace any leaking parts.
5t.
11-179