Honda Civic Service Manual page 217

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.
Svmotom
Diaqnostic procedure
Also check lor
E n g i n e w i l l n o t s t a r t
(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
1 4 1 ) .
Low compressron
N o i g n i t i o n s p a r k
l n t a k e a i r l e a k s
L o c k e d u p e n g i n e
B r o k e n t i m i n g c h a i n
Contaminated fuel
E n g i n e w i l l n o t s t a r t ( M l L
comes on and stays on, or
n e v e r c o m e s o n a t a l l , n o
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 . C h e c k t h e f u e l p r e s s u r e ( s e e p a g e 1 1 - 1 4 5 ) .
Low compression
I n t a k e a i r l e a k s
Contaminated fuel
Cold fast idle too low
(MlL works OK. no DTCS set)
1 . D o t h e E C M i d l e l e a r n p r o c e d u r e ( s e e p a g e 1 1 - 1 3 9 ) .
2 . C h e c k t h e i d l e s D e e d ( s e e p a q e 1 1 - 1 3 8 ) .
Cold fast idle too high
(MlL works OK, no DTCS set)
D o t h e E C I \ 4 i d l e l e a r n p r o c e d u r e ( s e e p a g e 1 1 - 1 3 9 ) .
C h e c k t h e i d l e s p e e d { s e e p a g e 1 1 - 1 3 8 ) .
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 . D o t h e E C M i d l e l e a r n p r o c e d u r e ( s e e p a g e 1 1 - ' 1 3 9 ) .
2 . C h e c k t h e i d l e s p e e d ( s e e p a g e 1 1 - 1 3 8 ) .
3, Inspecvadjust th e throttle cable (see page 11''163).
4. Insoect and test the throttle bodv (see paqe 11- 160)
I n t a k e a i r l e a k s
After warming up, idle speed
is below specifications with
no load
{MlL works OK, no DTCS set)
1 . D o t h e E C I V I i d l e l e a r n p r o c e d u r e ( s e e p a g e 1 1 - 1 3 9 ) .
2. Troubleshootthe alternator FR signal circuit (see
p a g e 1 1 - ' 1 3 4 ) .
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
n o t o a o
(MlL works OK. no DTCS set)
1 . D o t h e E C M i d l e l e a r n p r o c e d u r e { s e e p a g e 1 ' j - 1 3 9 ) .
2 . T r o u b l e s h o o t t h e a l t e r n a t o r F R s i g n a l c i r c u i t ( s e e
p a g e 1 1 - 1 3 4 ) .
Low power
(MlL works OK, no DTCS set)
1 . C h e c k t h e f u e l p r e s s u r e ( s e e p a g e l l - 1 4 5 ) .
2. Inspect and test the th roftle body (see page 11-160).
3 . I n s p e c v a d j u s t t h e t h r o t t l e c a b l e ( s e e p a g e 1 1 - ' 1 6 3 ) .
Low compressron
C a m s h a f t t i m i n g
problem
E n g i n e o i l l e v e l
p r o o t e m
E n g i n e s t a l l s
(MlL works OK. no DTCS set)
1 . D o t h e E C M i d l e l e a r n p r o c e d u r e ( s e e p a g e 1 ' l ' 1 3 9 ) .
2 . C h e c k t h e f u e l p r e s s u r e { s e e p a g e l l - 1 4 5 ) .
3 . C h e c k t h e i d l e s p e e d ( s e e p a g e I 1 - 1 3 8 ) .
4. Troubleshootthe brake pedal position switch signal
c i r c u i t ( s e e p a q e 1 1 - 1 3 7 ) .
l n t a k e a i r l e a k s
F a u l t y h a r n e s s a n d
sensor connections
\
\-
1 1 - 1 0
\-