Honda Civic Service Manual page 279

PGM-FI System
I
DTC Troubleshooting (cont'dl
DTC P0301: No. 1 Cylinder Misfire
DTC P0302: No. 2 Cylinder Misfire
DTC P0303: No. 3 Cylinder Misfire
DTC P0304: No. 4 Cylinder Misfire
1. After checking and recording the freeze data, reset
the ECM (see page 1 1-4). lf there is no freeze data of
the misfire, just clear the DTC.
2. Start the engine, and listen for a clicking sound
from the injector at the problem cylinder.
Does the injector click?
YES-Go to step 3.
NO-Go to step 30.
3. Turn the ignition switch OFF.
4. Exchange the ignition coil from the problem
cylinder with one from another cylinder,
5. Test-drive the vehicle for several minutes in the
range of the freeze data or under va rious
conditions if there was no freeze data.
6. Check for a DTC or a Temporary DTC with the scan
r o o t .
ls DTC or Tempotaty DTC P0301, P0302, P0303
or P0304 ind icated?
YES Go to step 7.
NO Intermittent misfire due to poor contact at the
i g n i t i o n c o i l c o n n e c t o r s { n o m i s f i r e a t t h i s t i m e ) .
Make sure the coil connections are secure.l
11-72
8 .
9 .
1 .
1 1 .
Determine which cylinder(s) had the misfire.
Does the misf ire occur in the cylinder where the
ignition coil was exchanged?
YES Replace the faulty ignition coil.!
NO-Go to step 8.
Turn the ignition switch OFF.
Exchange the spark plug from the problem cylinder
with one from another cylinder.
Test-drive the vehicle for several minutes in the
range of the freeze data or under various
conditions if there was no freeze data.
Check for a DTC or Temporary DTC with the scan
Tool.
ls DTC ot Tempotary DTC P0301, P0302, P0303
or P0304 ind icated?
YES Go to step 12.
NO Intermittent misfire due to spark plug fouling,
e t c . ( n o m i s f i r e a t t h i s t i m e ) . 1
D e t e r m i n e w h i c h c y l i n d e r ( s ) h a d t h e m i s f i r e .
Does the misl ire occur in the cylinder where the
spark plug was exchanged?
Y E S R e p l a c e t h e f a u l t y s p a r k p l u g . l
NO Go to step 13.
Turn the ignition switch OFF.
Exchange the lnjector from the problem cylinder
w i t h o n e f r o m a n o t h e r c y l i n d e r .
L e t t h e e n g i n e i d l e f o r 2 m i n u t e s .
1 0 .
1 4 .
t 5 .