2003 HONDA CIVIC fuse box

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

PGM-FI System
MIL Circuit Troubleshooting (cont'dl
11.
Try to start the engine.
Does the engine start?
YES-Go to step 11.
NO-Go to step 14.
Turn the ignition switch OFF.
Connect ECM connector terminal E31 to bodyground with a jumper wire.
10.
12.
ECM CONNECTOR E 13lPI
MIL(GRN/ORN}
Wire side of female terminals
Turn the ignition switch ON (ll).
ls the M lL on?
YES 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 ECIM, replace the
original ECM.I
NO-Check for an open in the wire between the
ECM (E31) and the gauge assembly. Also check for
a blown MIL bulb. lf the wires and the bulb are OK,
replace the gauge assembly.l
Turn the ignltion switch OFF,
Inspect the No. 6 ECU (ECIM) (15A) fuse in the
under-hood fuse/relay box.
ls the f use OK?
YES-Go to step 22.
NO-Go to step 16.
't 4.
15.
ll2l345617l 18I
415161,/ 1182(2t2'23 24z7l/ 12931
JUMPERWIRE
11-98
to.Remove the blown No. 6 ECU {ECfU) (154) fuse
from the under-hood fuse/relay box.
Remove the glove box (see page 20-63) and the
PGM'FI main relay 1.
Check for continuity between body ground and
PGM-Fl main relay 1 4P connector terminals No. 2
and No. 4 individuallv.
PGM-FI MAIN RELAY 14P CONNECTOR
Wrre srde ol lemale termrnals
ls there continuity?
YES-Repair short in the wire between the No.6
ECU (ECl\4) (15A) fuse and the PGM-Fl main relay 1.
Also replace the No.6 ECU (ECM) (15A) fuse.l
NO-Go to step 19.
17.
18.
fVBv) (wHr/
IA BLK)(

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

DLC Circuit Troubleshooting
lf the ECM does not communicate with the OBD ll scan
tool, Honda PGfM Tester, or l/M test equipment, do this
troubleshooting procedure.
1. Measure voltage between DLC terminal No. 16 and
body ground.
DATA LINK CONNECTOR {DLCI
(WHT/RED)
Terminal side of lemale terminals
ls therc battery voltage?
YES-Go to step 2.
NO-Repair open in the wire between DLC terminal
No. 16 and the No. 9 BACK UP (7.5 A) fuse in the
under-hood f use/relay box. I
Measure voltage between DLC terminals No. 4 and
No. 16.
DATA LINK CONNECTOR (DLCI
Terminal side of Jemale terminals
Is there battery voltage?
YES Go to step 3.
NO Repair open in the wire between DLC terminal
No. 4 and body ground.l
4.
5.
3. Measure voltage between DLC terminals No. 5 and
No. 16.
DATA LINK CONNECTOR {DLC)
Terminal side of female terminals
ls there battery voltage?
YES Go to step 4.
NO- Repair open in the wire between DLC terminal
No. 5 and the ECM (E3). t
Turn the ignition switch ON {ll).
Measure voltage between DLC terminals No.5 and
No.7.
DATA LINK CONNECTOR {DLCI
Terminal side of lemale terminals
ls there 8.5 V or more?
YES Go to step 10.
NO Go to step 6.
6. Turn the ignition switch OFF.
(cont'd)
11-109

DTC P0340: CMP Sensor A No Signal
DTG P0344: CMP Sensor A Intermittent
Interruption
1. Reset the ECM (see page '11-4).
2. Start the engine.
ls DTC P0340 and/or P0344 indicated?
YES-Go to step 3.
NO Intermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the CMP sensor A and at the ECM.I
3. Turn the ignition switch OFF.
4. Disconnect the CMP sensor A 3P connector.
5. Turn the ignition switch ON (ll).
6. Measure voltage between CMP sensor A 3P
connector terminal No. 3 and body ground.
CMP SENSOR A 3P CONNECTOR
(BLK/YEL}
Wire side of female terminals
ls there battety voltage?
YES Go to step 7.
NO Check the No. 4 ACG {10A) fuse in the under-
dash fuse/relay box. lf the fuse is OK, repair open in
the wire between the CN4P sensor A and No. 4 ACG
(10A) fuse.I
tG1
123
7. Measure voltage between CMP sensor A 3P
connector terminal No. 1 and body ground.
CMP SENSORA 3P CONNECTOR
Wire side olfemale termina s
ls therc about 5 V?
YES-Go to step 8.
NO-Go to step 10.
8. Measure voltage between CMP sensor A 3P
connector terminals No. 2 and No. 3.
CMP SENSOR A 3P CONNECTOF
;f-;-1 ,o, ,r.*,"r.,
I l1 J l-t
,-or---T--I{8RN/YEL) ni-
ls there battety voltage?
YES Go to step 9.
NO-Repair open in the wire between the Cl\4P
sensor A and G101.1
9. Substitute a known-good CMP sensor A and
recheck.
ls DTC P0340 and/ot P0344 indicated?
YES 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.I
NO Replace the original CMP sensor A {see page
11-128).t
(cont'd)
11-121

A/G Signal Circuit Troubleshooting
Turn the ignition switch ON (ll).
Momentarily connect ECM connector terminals 424
and E18 with a jumper wire several times.
1.
2.
5.
Wire side of female terminals
ls there a clicking noise I rom the NC compressor
clutch?
YES Go to step 3.
NO-Go to step 6.
Sta rt the engine.
Turn the blower switch ON.
Turn the Ay'C switch ON.
Does the NC operate?
YES-The air conditioning signal is OK.I
NO 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 €CM.l
6. Momentarily connect under-hood tuse/relay box
14P connector terminal No. 10 to body ground with
a jumper wire several times.
UNDER.HOOD FUSE/RELAY BOXI4P CONNECTOR
12356
1891011IJ14
ACC (RED)
JUMPER WIRE
Wire side of female terminals
ls there a clicking noise f rom the NC compressor
clutch?
YES- Repair open in the wire between the ECM(E'18) and the Ay'C clutch relay.l
NO- Check the A/C system for other symptoms.l
11-133

Brake Pedal Position Switch Signal Circuit Troubleshooting
1. Check the brake lights.
Are the brake lights on without pressing the brakepedal?
YES Inspectthe brake pedal position switch(see page 19-6).I
NO Go to step 2.
2. Press the brake pedal.
Do the brake lights come on?
YES-Go to step 3.
NO Go to step 4.
3. Measure voltage between ECM connector
terminals A24 and E22 with the brake pedal
presseo.
ls there battery voltage?
YES-The brake pedal position switch signal is
oK,I
NO Repair open in the wire between the Eclvl(E22) and the brake pedal position switch.l
Wire side of lemale terminals
4. Inspect the No. 7 HORN, STOP (15A) fuse ln the
under-hood fuse/relay box.
ls the tuse OK?
YES- Repair open in the wire between the brake
pedal position switch and the No.7 HORN, STOP( l5A) fuse, Inspect the brake pedal position switch(see page 19-10).1
NO Repair short in the wire between the ECM(E22) and the No.7 HORN, STOP (15A)fuse.
Replace the No.7 HORN, STOP (15A)fuse.t
11-137

ECM ldle Learn Procedure
The idle learn procedure must be done so the ECM can
learn the engine idle characteristics.
Do the idle learn procedure whenever you do any of
these actions:. Disconnect the battery.
Replace the ECM or disconnect its connector.
Reset the ECM.
NOTE: Erasing DTCS with the Honda PGM Tester
does not require you to do the idle learn procedure.
Remove the No.6 ECU {ECM) ( 15A) fuse from the
under-hood fuse/relay box.
Remove the No.19 baftery (80A) fuse from the under-
hood fuse/relay box.
Remove PGM-FI main relay 1.
Remove any of the wires from the under-hood fuse/
retay Dox.
Disconnect any of the connectors from the under
hood fuse/relay box.
Disconnect the connector between the engine
compartment wire harness and ECM wire harness.
Disconnect the G2 terminal from the transmission
ho u srng.
Disconnectthe G'l terminal from the body.
Disconnectthe G101 terminal from the cylinder head
cover.
Procedure:
To complete the idle learn procedure, do this:
1. Make sure all electrical items (Ay'C, audio, rear
defogger, l:ghts, etc.,) are off.
2. Start the engine, and hold it at 3,000 rpm with no
load {in neutral) until the radiator fan comes on, or
until the engine coolanttemperature reaches 194"F(90'c).
3. Let the engine idle for about 5 minutes with the
throttle fully closed.
NOTE: lf the radiator fan comes on, do not include its
running time in the 5 minutes.
11-139