fuel HONDA CIVIC 2003 7.G Repair Manual

DTC P0300: Random Misfire and Any Combination of the Following:
DTC P0301: No. 1 Cylinder Misfire
DTC P0302: No. 2 Cvlinder Misfire
DTC P0303: No, 3 Cvlinder Misfire
DTC P0304: No. 4 Cvlinder Misfire
NOTE:. lfthe misfiring is frequent enough to trigger detection of increased emissions during two consecutive driving cycles.
the MIL will come on, and DTC P0300 (and some comlrination of P0301 through P0304) will be stored.. lf the misfiring is frequent enough to damage the catalyst, the MIL will blink whenever the misfiring occurs, and OTC
P0300 (and some combination of P0301 through P0304) will be stored. When the misfirlng stops, the MIL will remain
on.
1. Troubleshoot the following DTCs first if any of them were stored along with the random misfire DTC(s):
P0'107, P0108, P1128, P1129r N4anifold absolute pressure (MAP) sensor
P0111. P0'172t Fuel svstem
P0335. P0336: Crankshaft position (CKP) sensor
P0505: ldle control system
P1 149, Pl 162, P1 163, P1 164, P 1 165: Air fuel ratio (Ay'F) sensor
P1259: VTEC system
P1361, P1362: Camshaft position (CMP) sensor B {Top dead center (TDC) sensor)
P1519: ldle air control (lAC) valve
2. Test-drive the vehicle to verify the symptom.
3. Findthesymptom inthechart below, and dothe related procedures in the order listed until you find the cause.
SymptomProcedure(slAlso check foi:
Random misfire only
at low RPM and
under load
Check fuel pressure (see page 1 1-145).. Low compressron.. Low quality fuel.
Random misfire only
du ring acceleration
Check fuel pressure (see page 11-145).Malfunction in the
VTEC system (see page
1't-123).
Random misfire at
high RPM, under
load, or under
random conditions
Check fuel pressure (see page 11-145).Correct engine valve
clearances (see page 6-
91.
11-71

MIL Circuit Troubleshooting
1. Connect an OBD ll scan tool/Honda PGM Tester
(see page 11-3).
2. Turn the ignition switch ON (ll) and read the OBD ll
scan tool/Honda PGM Tester.
Does the OBD ll scan tool/Honda PGM Tester
communicate with the ECM?
YES Go to step 3.
NO Go to troubleshooting " DLC Circuit
Troubleshooting" (see page 11-109).
3. Check the OBD ll scan tool/Honda PGM Testerfor
DTCs.
Are any DTCs ind icated?
YES Go to the DTC Troubleshooting Index.
NO-Go to step 4.
4. Turn the ignition switch OFF.
5. Turn the ignition switch ON (ll)and watch the
lMalfunction Indicator Lamp (MlL).
Does the MIL come on and stay on for more than
20 seconds aftet turning the ignition switch
oN (tr)?
YES lf the MIL always comes on and stays on, go
to step 76. But if the lMlL sometimes works
normally, first check for these problems.
. An intermittent short in the wire between the
ECIM (E29) and the data link connector (DLC).
. An intermittent short in the wire between the
ECM (E31) and the gauge assembly.
NO lf the MIL is always off, go to step 6. But if the
lvllL sometimes works normally, first check for
these problems.
. A loose No. 10 METER (7.5A) fuse in the under
dash fuse/relay box.. A loose No. 20 lG (40A) (Canada: 50A)Iuse in the
under-hood fuse/relay box.. A ioose No. 6 ECU (ECM) (15A) fuse in the under-
hood fuse/relay box.
. A loose No. 17 FUEL PUMP (15A)fuse in the
under-dash fuse/relay box.. A poor connection at ECM terminal E31.. An intermittent open in the GRN/ORN wire
between the ECM (E31) and the gauge assembly.. An intermittent short in the wire between the
ECM (A21) and the manifold absolute pressure
(MAP) sensor.. An intermittent short in the wire between the
ECI\4 (A20) and the throttle posilion (TPi sensor.. An intermittent short in the wire between the
ECM (E5) and the fuel tank pressure (FTP) sensor.
6. Turn the ignition switch OFF.
7. Turn the ignition switch ON (ll).
ls the low oil pressure light on?
YES Go to step 10.
NO-Go to step 8.
8. Inspectthe No. 10 l\4ETER (7.5A)fuse inthe under-
dash fuse/relay box.
ls the luse OK?
YES Go to step L
NO Repair shon in the wire between No. 10
METER (7.5A)fuse and the gauge assembly. Also
replacethe No. 10 METER {7.5A) fuse.l
9. Inspect the No. 20 lG1 (40A) (Canada: 50A) fuse in
the under-hood fuse/relay box.
ls the f use OK?
YES Repair open in the wire between the No. 20
lG (40A) {Canadar 50A)fuse and the gauge
assembly. lf the wire is OK, test the ignition switch
{see page 22 53).
NO Repair short in the wire between No. 20 lG
(40A) lCanada: 50A)fuse and the under'dash fusel
relay box. Also replace the No.20 lG (40Ai
(Canada: 50A) fuse.I
(conr'd)
11-97

19. Disconnect each of the components or the
connectors below, one at a time, and check for
continuity between PGM-FI main relay 1 4P
connector terminal No. 1 and body ground.
. PGfvl-Fl main relay 2. ECM connector A (31P)
. Each injector 2P connector. ldle air control (lAC)valve 3P connector. Camshaft Position (CMP) sensor B (Top dead
center (TDC) sensor) 3P connector. Crankshaft position (CKP) sensor 3P connector
PGM-FI MAIN RELAY 14P CONNECTOR
ls thete continuity?
YES Go to step 20.
NO- Replace the component that made continuity
to body ground go away when disconnected. lf the
item is the ECM, update the ECM if it does not have
the latest software. or substitute a known-good
ECM, then recheck (see page 11-6). lf the symptom/
indication goes away with a known'good ECM,
replace the original ECM.
Also replace the No. 6 ECU (ECM) (15 A) fuse,
Disconnect the connectors of all these components.
. PGM-Fl main relay 2. ECM connector A (31P)
. lnjectors. ldle air control (lAC)valve
. Camshaft Position {CMP) sensor B (Top dead
center (TDC) sensor). Crankshaft position (CKP) sensor
20.
Wire side of female terminals
22.
21. Check for continuity between PGM-FI main relay 1
4P connector termlnal No. 1 and body ground.
PGM-FI MAIN RELAY 14P CONNECTOR
ls there continuity?
YES Repair short in the wire between the PGM-Fl
main relay 1 and each item. Also replace the No. 6
ECU {ECM) (15A) fuse.l
NO-Replace the PGM-Fl main relay 1. Also replace
the No 6 ECU {ECIM) (15A) f use. I
Inspectthe No. 17 FUEL PUI\4P (15A)fuse in the
under-dash f use/relay box.
ls the tuse OK?
YES Go to step 34.
NO Go to step 23.
Remove the blown No, 17 FU EL PUMP (15A) fuse
from the under-dash fuse/relay box.
Disconnect ECfvl connector E (31P).
(conr'd)
23.
24.
Wire side of female terminals
11-99

PGM-FI System
25.
MIL Circuit Troubleshooting (cont'dl
Check for continuity between ECM connector
terminal E9 and body ground.
ECM CONNECTOR E (31P)
Wire side o{ {emale terminals
ls therc continuity?
YES-Go to step 26.
NO Replace the No. lTFUELPUMP(15A)fuse,
and update the ECM if it does not have the latest
software. or substitute a known-good ECM, then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM. replace the
original ECM.I
26. Remove the PGM-Fl main relay 2 (A).
11-100
27. Check for continuity between ECIVI connector
terminal Eg and body ground.
ECM CONNECTOR E 131P)
Wire side oI Jemale terminals
ls there continuity?
YES Repair short in the wire between the No. 17
FU EL PUMP (15A)fuse and the ECM (E9), or
between the No. 17 FUEL PU MP (15 A) fuse and the
PGM-FI main relay 2. Also replace the No. 17 FUEL
PUMP (15A)fuse.l
NO Go to step 28.
Remove the rear seat cushion (see page 20-80).
Remove the access panel from the floor.
Disconnect the fuel pump 5P connector.
\
28.
29.
30.

31. Check for continuity between fuel pump 5P
connector terminal No. 5 and body ground.
FUEL PUMP 5P CONNECTOR
Wire side of temale terminals
ls therc continuity?
YES Repair short in the wire between the fuel
pump and the PGM-Fl main relay 2. Also replace
thE NO. 17 FUEL PUMP (15A) fUSE.T
NO-Go to step 32.
32. Reinstallthe PGM-Fl main relay 2 (A).
33. Check for continuity between fuel pump5P
connector terminal No. 5 and body ground.
FUEL PUMP 5P CONNECTOR
=
Wire side ol lemal€ rerminals
ls there continuity?
YES Replace the PGM-Fl main relay 2. Also
replace the No. 17 FUEL PUMP (15A) fuse.l
NO Check the iuel pump, and replace il if
necessary. Also replace the No. 17 FUEL PUMP(15A) fuse.!
34. Disconnect ECM connector E (31P).
35. Turn the ignition swirch ON {111.
36. Measure voltage between ECM connectorterminal
E9 and body ground.
ECfl CON|{CCIOR E (3rPt
Wire side ol female lerminals
ls there battery voltage?
YES Go to step 37.
NO Repair open in the wire between the No. 17
FUEL PUMP (15A)fuse and the ECM (E9).1
(cont'd)
11-101

PGM-FI System
67.
MIL Circuit Troubleshooting (cont'd)
Check for continuity between ECIM connector
terminal A20 and body ground.
ECM CONNECTOR A (31P)
rl2l3145ot/9
10t1121,/ 1,/1516ta,92A21
22 '3241 12526n
o
Wire side of female terminals
ls there continuity?
YES Repair shon in the wire between the ECN4
{A20) and the TP sensor, or repair short in the wire
between the ECM (A8) and the knock sensor. t
NO Update the ECM if it does not have the latest
software. or substitute a known-good ECM, then
recheck (see page l1-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.t
vcc2{YEL/BLU}
11-106
68. Measure voltage between body ground and ECM
connector terminal E5.
ECM CONNECTOR E (31PI
Is there about 5 V?
YES U pdate the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good EClvl, replace the
original ECM.t
NO-Go to step 69.
Turn the ignition switch OFF.
Disconnect the fuel tank pressure (FTP) sensor 3P
connector.
Turn the ignition switch ON (ll).
69.
70.
11.
Wire side of female terminals

Injector Replacement
Relieve fuel pressure (see page 1 l-144).
Disconnect the connectors from the injectors (A), disconnect the ground cable (B), and remove the bracket (C).
(2.2 kgf.m, l6 lbf.ftl
ffi \*\
3. Disconnect the quick-connect fittings (D).
4. Removethefuel rail mountingnuts(E) fromthefuel rail (F)then removethefuel rail and injectors asan assembly.
5. Remove the injector clip (G)from the injector.
6. Remove the injector from the fuel rail.
(cont'd)
11-111
1.
2.
o

PGM-FI System
Injector Replacement (cont'd)
7. Coatthenewo-rings(A)withcleanengineoll,andinserttheinjectors(B) intothefuel rail (C).
8, lnstall the injector clip {D).
9. Coat the injector o-rings (E)with clean engine oil.
10. Installthe injectors intothefuel rail, then install the fuel rail intotheintakemanifold(G).
1 '1. Install the fuel rail mounting nuts, ground cable. and bracket.
12. Connect the connectors to the injectors.
13. Connect the quick-connect fittings.
14. Turnthe ignition switch ON (ll), butdo notoperatethe starter. Afterthefuel pump runs for about 2 seconds, the
fuel pressure in the fuel line rises. Repeat this two or three times. then check for fuel leakage.
\
11-112

Fuel Supply System
{
a
Component Location Index
FUEL FEED LINEFUEL PULSATION DAMPERReplacement, page 1 1'154
PGM.FI MAIN RELAY 2Troubleshooting, page'l'l-141
FUEL TUBE/OUICK.CONNECT FITTINGSPrecautions, page 1 1-148Removal, page 11-'149Installation, page 1 1-'l50
FUEL VAPOR LINE
i../
PUMPTest, page 11-141
FUEL FILL CAP
FUEL TANKReplacement, page'l 1-155
PGM.FI MAIN RELAY 1
Fleplacement, page 1 1'1 53FUEL FILTERReplacement, page 1 1-1 52FUEL GAUGE SENDING UNITTest, page 11-156Replacement, page 1 1-153FUEL PRESSUN REGULATORReplacement, page'1 1-'152
11-140

Fuel Pump Circuit Troubleshooting
lf you suspect a problem with the fuel pump, check that
the fuel pump actually runs; when it is on, you will hear
some noise if you listen to the fuel fill port with the fuel
fill cap removed. The fuel pump should run for 2
seconds when the ignition switch is first turned on. lf
the fuel pump does not make noise, check as follows:
1. Turn the ignition switch OFF.
2. Remove the glove box {see page 20-63), then
remove the PGM-FI main relay 2 (A).
Turn the ignition switch ON {ll).
Measure voltage between PGM-Fl main relay 2 5P
connector lerminal No. 5 and body ground.
PGM.FI MAIN RELAY 25P CONNECTOR
IGPl(YEL/BLK}
Wire side of female terminals
ls there battery voltage?
YES-Go to step 5.
NO Repair open in the wire between the PGM'Fl
main relay 1 and the PGM-Fl main relay 2.t
3.
5. N4easure voltage between PGM-Fl main relay 2 5P
connector terminal No. 1 and body ground.
PGM.FI MAIN RELAY 25P CONNECTOR
Wire side oJ female terminals
ls there battery voltage?
YES Go to step 6.
NO Repair open in the wire between the under-
dash fuse/relay box and PGM-Fl main relay 2.1
6. Turn the ignition switch OFF.
7. Disconnect ECM connector E (31P).
8. Check for continuity between PGM-FI mainrelay2
5P connector terminal No. 3 and ECM connector
terminal E1.
PGM-FI MAIN RELAY 2 5P CONNECTOB
Wire side of female terminals
ls there continuity?
YES-Go to step 9.
NO-Repair open in the wire between the PGM Fl
main relay 2 and the ECM (E1).1
IMOFPR(GBN/YEL)
(cont'd)
11-141
Et2lFtxm
7-
z
ECM CONNECTOR E 131P}