2003 HONDA CIVIC under-dash

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

EPS Indicator Circuit Troubleshooting
1.Turn the ignition switch ON (ll), start the engine,
and watch the EPS indicator.
Does the EPS indicator come on?
YES lf the EPS indicator comes on and goes off, it's
OK. lf the EPS indicator stays on or blinks. go to
step 12.
NO Go to step 2.
Turn the ignition switch OFF, then ON (ll) again,
and watch the brake system indicator,
Does the brake system indicator come on?
YES-Go to step 3.
NO Repair open in the indicator power source
circuit.l. Blown No. 10 (7.5A)fuse.
. Open in the wire between the No. 10 (7.5A) fuse
and gauge assembly.. Open circuit inside the under-dash fuse/relay box,. Faulty gauge assembly.
Turn the ignition switch OFF,
Connect a jumper wire between the gauge
assembly 22P connector terminal No. 13 and body
ground, then turn the ignition switch ON (ll).
GAUGE ASSEMBLY 22P CONNECTOR (Blue connector)
Wire side of female terminals
Does the EPS indicator come on?
YES-Go to step 5.
NO Inspect the EPS indicator bulb, if the bulb is
OK, replace the bulb circuit board in the gauge
assembly.l
3.
4.
5. Turn the ignition switch OFF.
6. Disconnect EPS control u n it connector C (20P).
7. Turn the ignition switch ON (ll).
8. Connect EPS control unit connector C (20P)
terminal No. 6 to body ground with a jumper wire.
Wire s d€ oflemale16rmina s
Does the EPS indicatot come on?
YES Go to step 9.
NO Repair open in the wire between the gauge
assembly and the EPS control unit.l
Turn the ignition switch OFF.
Disconnect EPS control unit connector A (2P),
Check for continuity between EPS control unit
connector A terminal No. 2 and body ground.
EPS CONTROL UNITCONNECTOA A I2PI
wire s de oftemale terminals
ls there continuity?
YES Check for loose or poor connections at the
EPS control unit. lf the connections are good,
substitute a known-good EPS control unit. lf the
symptom/indication goes away, replace the
original EPS control unit and recheck.I
NO Repair open in the wire or a bad ground at
G151,t(cont'd)
9.
10.
'l 1.
EPS CONTBOL UNIT CONNECTOB C {2OP)
17-47

DTC 54: Main Relay Stuck OFF
1. Checkthe No.8 (20A) fuse in the under-hood fuse/
relay box, and reinstallthe fuse if it is OK.
ls the f use OK?
YES-Go to step 2.
NO Replace the fuse, and recheck.l
2. Disconnect the ABS control unit 31P connector.
3. l\4easure the voltage between the ABS control unit
connector terminal No. 18 and body ground.
ABS CONTROL UNIT 31P CONNECIOR
Wire side of female terminals
Is there battety voltage?
YES Replace the ABS modulator-control unit.l
NO-Repair open in the wire between the ABS
control unit and the under-hood fuse/relay box.I
DTC 61: lG2 Voltage
NOTE: Check the No. 11 (7.5A) fuse in the under-dash
fuse/relay box before troubleshooting.
1. Clear the DTC, then disconnect the Honda PGM
tesler.
2. Test drive the vehicle.
Doesthe ABS indicator come on and is DTC 61
ind icated ?
YES Go to step 3.
NO The system is OK at this time.l
3. Disconnect the ABS control unit3lPconnector.
4. Turn the ignition switch ON (ll).
5. Measure the voltage between the ABS control unit
31P connectorterminal No. 15 and body ground.
ABS CONTROL UNIT 31P CONNECTOR
ls there battery voltage?
YES Replace the ABS modulator-control unit.l
NO - Repair open in the wire between the ABS
control unit and the under-hood {use/relay box.l
Wire side of female terminals
19-51

8.
9.
Disconnect the gauge assembly connector A (22P).
Check for continuity between gauge assembly
connector A {22P) terminal No, 12 and body ground.
GAUGE ASSEMBLY CONNECTOR A (22P)
Wire side of female terminals
ls there continuity?
YES- Repair shon to body ground in the wire
between the gauge assembly and the ABS control
unit.l
NO Go to step 10.
Disconnect the gauge assembly connector B (22P).
Check for continuity between gauge assembly
connector B (22P) terminal No. 12 and body ground.
GAUGE ASSEMBLY CONNECTOR B (22PI
Wire side ol Iemale terminals
ls there continuity?
YES Check for loose terminals in the gauge
assembly connectors. lf the connectors are OK,
replace the gauge assembly.l
NO Repair open in the wire between the gauge
assembly and body ground (G501).1
'10.
11.
3.
ABS indicator does not go off
1. Checkthe No. 8 (20Alfuse in the under-hood fuse/
relay box, and reinstall the fuse if it is OK.
ls the fuse OK?
YES Go to step 2.
NO-Replace the fuse, and recheck. lf the fuse is
blown, check for a shon to body ground in this fuse
circuit. ll the circuit is OK, replace the ABS
modulator-control unit. I
Check the No. 11 (7.5A) fuse in the under-dash
fuse/relay box, and reinstall the fuse if it is OK.
ls the f use OK?
YES Go to step 3.
NO Replace the fuse, and recheck. If the fuse is
blown, check for a short to body ground in this fuse
circuit. lf the circuit is OK, replace the ABS
modulator-control unit. I
Disconnect the ABS control unit 31P connector.
Measure the voltage between terminal No. l8 and
body ground.
A8S CONTROL UNIT3lP CONNECTOR
ls there battery voltage?
YES-Go to step 5.
NO Repair open in the wire between the No. 8
(20A) fuse and the ABS control unit.l
(cont'd)
Wire side of female terminals
19-53

Driver's side:
7. From under the dash, disconnect the interior wire
harness connector (A), driver's door wire harness
connectors (B), side turn signal light connector (C).
roof antenna connector (D), antenna lead (E). clutch
switch connectors (F), and brake switch connector(G), and disconnect the floor wire harness
connectors (H) and engine compartment wire
harness connectors (l)from the under-dash fuse/
relav box (J).
Middle portion:
8. Disconnect the floor wire harness connectors (A)
and combination subharness connector (B).
Passenger's side:
9. From under the dash, disconnect the dashboard
wire harness connectors (A), EPS subharness
connectors (B), engine compartment wire harness
connectors (C), A,/C subharness connectors (D),
passenger's door wire harness connectors {E), and
side turn signal light connector (F).
10. Detach all of the harness and connector clips.
(cont'd)
20-67

Heating and Air Conditioning
{
a
a
SvmptomDiagnostic procedureAlso check for
Recirculation control doors do not
change between Fresh and Recirculate
Recirculation Control Motor
Circuit Troubleshooting (see page
21 251
Cleanliness and tightness of all
connectors
Both heater and Ay'C do not workHeater Control Power and Ground
Circuits Troubleshooting (see
page 21-27)
Blown fuse No. '14 (10A) in the
under-dash fuse/relay box
Poor ground at G501
Cleanliness and tightness of all
conneclors
Condenser fan does not run at all (but
radiator fan runs with the Ay'C on)
Condenser Fan Circuit
Troubleshooting {see page 21-28)
. Poor ground at G301. Cleanliness and tightness of all
connectors
Both fans do not run with the A,/C onRadiator and Condenser Fans
Common Circuit Troubleshooting
(see page 21-29)
Blown fuse No. 1 (20A) and No.4
(20A) in the under-hood fuse/relay
box
Poor ground at G30l
Cleanliness and tightness of all
connectors
Compressor clutch does not engage(both fans run with A,/C on)
Compressor Clutch Circuit
Troubleshootinq (see Daqe 21-30)
Cleanliness and tightness of all
connectors
A/C system does not come on (both
fans and compressor)
Ay'C Pressure Switch Circuit
Troubleshooting (see page 21-32)
Blown fuse No. 1 (20A) and No. 4
(20A) in the under-hood fuse/relay
box
Poor ground at G301
Cleanliness and tightness of all
connectors
\Symptom Troubleshooting Index
\
21-10
!

Heating and Air Gonditioning
DTC Troubleshooting {cont'd)
DTC 12: A Problem in the Blower Motor
Circuit
'1. Check the No. 12 (40A)fuse inthe under-hood
fuse/relay box, and the No. 14 (10A) fuse in the
under-dash f use/relay box.
Are the tuses OK?
YES-Go to step 2.
NO Replace the fuse(s), and recheck.l
2. Connect the No. 2 terminal of the blower motor 2P
connector to body ground with a jumper wire.
BLOWER MOTOB 2P CONNECTOR
JUMPER ] BLU/BLK
Wire side ol female terminals
3. Turn the ignition switch ON (ll).
Does the blowet motor run?
YES Go to step 4,
NO Go to step 17.
4. Turn the ignition switch OFF.
5. Disconnect the jumper wire.
6. Disconnect the power transistor 4P connector.
21-20
8.
7. Check for continuity between the No. 3 terminal of
the power transistor 4P connector and body ground.
POWER TRANSISTOR 4P CONNECTOR
Wire side ol temale terminals
ls there continuity?
YES-Go to step 8.
NO-Check for an open in the wire between the
power transistor and body ground. lf the wire is OK,
check for poor ground at G502.I
Connect the No. 1 and No. 3 terminals of the power
transistor 4P connector with a jumper wire.
POWER TRANSISTOR 4P CONNECTOR
Wire side of female terminals
Turn the ignition switch ON (ll).
Does the blower motor tun at high speed?
YES-Go to step 10.
NO-Repair open in the wire between the power
transistor and the blower motor.l
Turn the ignition switch OFF.
Disconnect lhe jumper wire.
9.
10.
11.
2
34
BLK
o