Honda Civic Service Manual page 466

ldle Gontrol System
ldle Air Control (lAG) Valve ('99 - 00 Dl6Y8 engine with M/T, Bt6A2 enginel
[Fl50g l ]h"
scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt AC) vatve
-
C t r C U t t .
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM in
order to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR IC138'
la
rcpr
I - {YEL/8LKI
\
2 t -
- d ,
Y
-=
W i r e s i d e o t f e m a l e t e r m i n a l s
W i r e s i d e o f l e m a l e t e r m i n a l s
VALVE
The MIL has boon r€oorted on.
DTC P1508 is srored.
Probl6m verification:
1. Do the ECM/PCM Reset Pro-
cedure.
2. Start the engine, and warm it
up to normal operating lem-
perature.
Intermittent tailure, system is OK
at this timg. Check to. poor con-
noctions or loose wires at C138
{lAC valvel and ECM.
ls DTC P1508 indicated?
Ch6ck for an open in the wir€
{lGPl lino}:
1. Turn the ignition switch OFF.
2. Disconnect the IAC valve 2P
connector.
3. Turn the ignition switch ON (ll).
4. Measure voltage between body
ground and the IAC valve 2P
conneclor termina I No.2,
Repair opon in the wire bgtwoen
IAC valve and PGM-Fl main relay.
Check tof an open or short in the
wire {IACV line}l
1. Turn the ignition switch OFF
and reconnect the IAC valve
2. Disconnect the ECM connector
B {25P).
3. Turn the ignition switch ON (ll).
4 . M e a s u r e v o l t a g e b e t w e e n
b o d y g r o u n d a n d E C M c o n
n€ctor terminal 823.
( T o p a g e 1 1 - 1 9 7 )
1 1 - 1 9 6