2003 HONDA CIVIC iac

Fuel and Emissions Systems
System Descriptions (cont'dl
ldle Control System Diagram
The idle speed of the engine is controlled by the ldle Air Control (lAC) varve:
'Aftertheenginestarts,theIACvalveopensforacertainamountoftime.Theamountofairisincreasedtoraisethe
idle sDeed.. When the engine coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. Theamount of bypassed air is controlled in relation to engine coolant temperature.
INTAKE MANIFOLDIAC VALVEAKE AIR DUCT
CLEANER
\
BLK/REO
YEL/BLK ---< FromPGM.FIMAINRELAY
THROTTLE AODY
Intake Air System Diagram
This system supplies air for engine needs. A resonator in the intake air
drawn into the svstem.
VARIOUSSENSOnS
pipe provides additional silencing as air is
THROTTLE AODYVARIOUSSENSORS
BLK
BLK
I
11-36
{

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

DTC Pl519: IAC Valve Circuit Malf unction
1. Resetthe ECM (see page 11-4).
2. Turn the ignition switch ON (ll)
ls DTC P 1519 indicated?
YES Go to step 3.
NO-lntermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the IAC valve and at the ECM.I
3. Turn the ignition switch OFF.
4. Disconnect the IAC valve 3P connector.
5. Turn the ignition switch ON (ll).
6. Measure voltage betlveen IAC valve 3P connector
terminal No. 2 and body ground.
IAC VALVE 3P CONNECTOR
IGP {YEL/BLK)
Wire side of female terminals
ls there battery voltage?
YES Go to step 7.
NO-Repair open in the wire between the IAC valve
and the PGM-Fl main relay 1.1
Turn the ignition switch OFF.
123
7.
8, Check for continuity between body ground and IAC
valve 3P connector terminal No. 1.
IAC VALVE 3P CONNECTOR
123
PG1 {BLK}
a.
Wire side of lemale terminals
Is there continuity?
YES-Go to step 9.
NO Repair open in the wire between the IAC valve
and G'101.1
Disconnect ECM connector A (31P)
Check for continuity between body ground and
ECM connector terminal A12.
ECM CONNECTOR A 131P)
r l2l3l4 5617s
r01l12 .// 1156 ./118192C21
da25126l27ln2930
IACV {BLK/RED}
1,)
Wire side oJ Jemale terminals
ls there continuity?
YES-Repair short in the wire between the IAC
valve and the ECM (A12).1
NO Go to step 1 1.
9.
10.
LCOnI Ol
11-131

ldle Control System
(DTC Troubleshooting (cont'd)
11. Connect IAC valve 3P connector terminal No.3 to
body ground with a jumper wire.
IAC VALVE 3P CONN€CTOR
IACV IBLK/REO}
JUMPER WIRE
Wire side of female terminals
Check for continuity between ECM connector
terminalAl2 and body ground.
ECM CONNECTOR A 131P)
Wire side of female terminals
ls there continuity?
YES Go to step 13.
NO-Repair open in the wire between the IAC valve
and rhe EcM (A12).r
Reconnect the IAC valve 3P connector.
Turn the ignition switch ON (ll).
13.
14.
11-132
15. Measure voltage between body ground and ECM
connector terminal A12.
ECM CONNECTOR A 131P}
rl2l31456179
t01tl12l,/l/tc6,/ 1182C2122231?4l| 12.zil2830
IACV IBLK/RED)
Wire side ol female terminals
I s there battery voltage?
YES-Update the ECI\4 if it does not have the latest
software, 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 ECI\4.1
NO-Replace the IAC valve.I!

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

25. Support the subframe with the subframe adapter
and a jack.
---
26.
EOS02C000011
Make reference marks (A) on the front suspension
subframe (B) and mounting bolts (C). then remove
the front suspension subframe.
27. Remove the clutch cover.
28. Remove the front engine mount.
Place the transmission iack under the transmission,
and remove the transmission mounting bolts.
29.
(cont'd)
13-7

Manual Transmission
\
12 x 1.25 mm64 N.m{6.5 ksf.m,47 tbf.ft)
30.
Transmission Removal (cont'd)
Pull the transmission away from the engine until
the transmission mainshaft clears the clutchpressure plate, then lower the transmission on the
transmission jack.
Remove the transmission rear mount (A) and the
transmission rear mount bracket {B).
Remove the boot (A), the release fork {B). and the
release bearing (C) from the transmission (D).
32.
13-8
Transmission Installation
Special Tools Required. Engine hanger adapter, 2.0 to 2.4 liter VS802C000015. E ngine hanger VS802C000018. Engine support hanger, A & Reds AAR-T-12566". subframe adaDter EoS02c000011* Available through the Honda Tool and Equipment
Program 888-424-6857
1. Check the two dowel pins are installed in the clutch
housr ng.
Apply super high temp urea grease (P/N 08798-
9002) to the release fork (A) and the release bearing(B). Installthe release fork and the release bearing.
0.4 1.0 g {0.01 0.04 ozl
3. Installthe transmission rear mount bracket (A)and
the transmission rear mount (B).
x 1.25 mmN m {6.5 kgf.m,
Place the transmission on the transmission iack.
and raise it to the engine level.
't2
6447
1.0 '1.6 g{0.04 0.06 oz)