Honda Civic Service Manual page 461

1 . After the engine starts, the lAc valve opens for a certain time. The amount
of air is increased to raise the idle speed
about 150 - 300 rpm.
When the coolant temperature is tow, the IAC valve is opened to obtain the
proper fast idle speed. The amount of
bypassed air is thus controlled in relation to the engine coolant temperature'
IOLE SPEED
lrpml
1 7 6
80
ENGI E
COOLANI TEMPERATURE
t " F l
t o c )
l l
't.
W h e n t h e i d | e s p e e d i s o u t o f s p e c i i i c a t i o n a n d t h e s c a n t o o | d o e s n o t i n d i c a t e D i a g n o s t i c T r o u b | e c o d e ( D T c ) P 0 5
or P1508. check the following items:
. Adiust the idle speed {see page 11-220}
.
Starter switch signal (see page 11-202)
. Air conditioning signal (see page l1-204)
. ALT FR signal (see Page 11-2081
'
Brake switch signal (see page 11-210)
.
PSP switch signal (excapt Canada model) (see page 11-212)
. A,/T gear position signal {see section 14, Dl6Y5 engine (CVT):
p a g e 1 1 - 2 1 6 )
.
Clutch switch signal (D16Y5 engine with M/T) (see page 11-218)
.
Hoses and connections
' IAC valve and its mounting O-rings
lf the above items are normal, substitute a known-good IAC valve and readjust
the idle speed (see page 11-220)
| f t h e i d | e s p e e d s t i | | c a n n o t b e a d j u s t e d t o s p e c i f i c a t i o n ( a n d t h e s c a n t o o | d o e s n o t i n d i c a t e D T c P 0 5 0 5 o r
after IAC valve replacement. substitute a known-good ECM/PCM and recheck.
lf symptom goes away, replace the
original ECM/PCM.