Honda Civic Service Manual page 436

PGM-FI System
Random Misfire
lFoioo l*u o, [FTioo l*' *' and
The scan tool indicates Diagnostic Trouble Code (DTC)
P 0 3 0 0 * 5 o r P 1 3 0 0 * 3 * 1 a n d s o m e o f P 0 3 0 1 - P 0 3 0 4 :
Random misfire.
Description
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensor
which is attached to the crankshaft.
lf misfiring strong enough to damage the catalyst is detected. the MIL will blink during the time of its occurrence, and DTC
P0300*5 or P1300*3'*' and some of DTCs P0301 through P0304 will be stored. Then, after misfire has ceased, the MIL will
come on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC
P0300*5 or P1300*3 *a and some of DTCS P0301 through P0304 will be stored.
NOTE: lf some of the DTCS listed below are stored at the same time as a misfire DTC. troubleshoot those DTCS first, then
recheck for the misfire DTC.
P0106*4. P0107. P0108, P1128*3 *5, Pl129*3 *5; MAP sensor
P 0 1 3 1 . P 0 1 3 2 : H O 2 S
P0171, P0112i Fuel metering
P0401, P 1491, P1498: EGR svstem*1
P0505: ldle Control System
P1253: VTEC System*,
P 1 3 6 1 , P 1 3 6 2 : T D C s e n s o r
P1381, Pl382: CYP sensor
P1508: IAC valve
Possible Cause
. Fuel pump insufficient fuel pressure, amount of flow
. Fuel line clogging, blockage, leakage
. Fuel filter clogging
. Fuel pressure regulator stuck open
. EGR system malfunction*1
. Distributormalfunction
. lgnition coil wire open. leakage
*l: D16Y5 engine
. lgnition control module malfunction
*2: D16Y5, D16Y8, Bt6A2 engine
. MAP sensor range/performance, poor response*r
*3: '97 models
. Valves carbon deposit
*4;'96 models
. Compression low
*5: '98 - 00 models
. IAC valve malfunctionr.
. VTEC system malfunction*,
.
Fuel does not meet Owner's Manual spec., lackoffuel
. HO2S
.
HO2S circuit
Troubleshooting
By test-driving, determine the conditions during which misfire occurs, Depending on these conditions, test in the order
described in the table below.
\
Possible
\
- - - ^ - - -
\
rage
cause
E G R * 1
system
Crankshaft
position (CKP)
sensor
Fuel
pressure
Distributor and
lgnition wires
t c M
Clearance
tAc
Valve
MAP
sensor
section 6
11-230,
231
section 23 section 23 section 6 1 1 - 1 9 4 11
Only low rpm and
load
o
@ @
o o
Only accelerating @
o
@ @
Only high rpm and
t o a o
o
o
@
Not specific
o o
@
NOTE: lf misfire doesn't recur, some possible causes are fuel that doesn't meet owne/s manual
spec, lack of fuel, carbon deposits on spark plug, etc.
1 1 - 1 6 6
I
P0304