2003 HONDA CIVIC fuel pump

Vacuum Hose Routing
I
O AIR FUEL RATIO IA/F) SENSOR {SENSOR 1}O SECONDARY HEATED OXYGEN SENSORISECONDARY HO2S} {SENSOR 2}
O MANIFOLD ABSOLUTE PRESSURE (MAPI SENSORO ENGINE COOLANT TEMPERATURE {ECT) SENSORO INTAKE AIR TEMPERATURE (IAT) SENSORO CRANKSHAFT POSITION (CKP) SENSORO KNOCK SENSORO CAMSHAFT POSITION (CMPI SENSOR BITOP DEAD CENTER ITDC) SENSOR)
O CAMSHAFT POSITION ICMPI SENSOR A@ IDLE AIR CONTROL (IACI VALVEO THRONLE BODY.O INJECTOR@ FUEL PULSATION OAMPER[I FUEL FILTER@ FUEL PRESSURE REGULATOR@ FUEL PUMP@ FUEL TANK
@ RESONATOR(9 AIR CLEANER@ POSITIVE CRANKCASE VENTILATION {PCVI VALVE@ THREE WAY CATALYTIC CONVERTER@ EVAPORATIVE EMISSION {EVAPI CANISTER@ EVAPORATIVE EMISSION {EVAP) CANISTERPURGE VALVE{} EVAPORATIVE EMISSION (EVAPI CANISTERVENT SHUT VALVE{' EVAPORATIVE EMISSION {EVAP) TWO WAY VALVE@ EVAPORATIVE EMISSION IEVAPI BYPASSSOLENOID VALVE@ FUEL TANK PRESSURE (FTP) SENSOR@ EVAPORATIVE EMISSION IEVAP} VALVE@ FUEL TANK VAPOR CONTROL VALVE60) FUEL TANK VAPOR RECIRCULATION VALVEO INTAKE AIR BYPASS CONTROL THERMAL VALVE
(cont'd)
11-25

wEc/wc
The i-WEC has a VTC (Variable Valve Timing Control) mechanism on the intake camshaft in addition to the usual
VTEC.
This mechanism improves fuel efficiency and reduces exhaust emissions at all Ievels of engine speed, vehicle speed.
and engine load.
The VTEC mechanism changes the valve lift and timing by using more than one cam profile.
The VTC changes the phase of the intake camshaft via oil pressure. lt changes the intake valve timing continuously.
HIGH
i
LOW <-ENGINE SPEED
Drivino ConditionVTC ControlDescriDtion
Qr Light-loadBase PositionCam angle is retarded to reduce the entry of exhaust
gas into the intake port and to achieve stable fuel
consumDtion durinq lean bu rn.
?l M ed iu m/h ig h-loadAdvance ControlCam angle is advanced for EGR effect and to reduce
this pumping loss. The intake valve is closed quickly
to help reduce the entry of airlfuel mixture into the
intake port and improve the charging effect.
€) High speedAdvance-Base PositionCam phase angle is controlled for optimum valve
timinq and maximum enoine oower.
{cont'd)
11-29

Fuel and Emissions Systems
(System Descriptions (cont'dl
VTC system. The VTC system makes continuous intake valve timing changes based on operating conditions.. Intake valve timing is optimized to allow the engine to produce maximum power.'CamangleisadvancedtoobtaintheEGReffectandreducethepumpingloss.Theintakevalveisclosedquicklyto
reduce the entry of the airlfuel mixture into the intake port and improve the charging effect.. Cam angle is reduced at idle to stabilize combustion and reduces engine speed.'lfamalfunctionoccurs,theVTCsystemcontrol is disabled and the valve timing is fixed at the fully retarded position.
MAXIMUM VTC ADVANCE 50'
i l(-4 sHoRT oVERLAP
'+-|l LoNG oVERLAP
VTEC system' The VTEC system changes the cam profile to correspond to engine speed. lt maximizes torque at low engine speedand output at high engine speed.. The low lift cam is used at low engine speeds, and the high lift cam is used at high engine speeds.
LOW SPEED VALVE TIMINGHIGH SPEED VALVE TIMING
TDC
MAXIMUM VTC ADVANCE 50'
11-30

Fuel and Emissions Systems
(
{
System Descriptions (cont'd)
ldle Control System
When the engine is cold, the Ay'C compressor is on, the
transmission is in gear, the brake pedal is pressed. thepower steering load is high, or the alternator is
charging, the ECIM controls current to the ldle Air
Control (lAC) valve to maintain the correct idle speed.
Refer to the System Diagram to see the functional
layout of the system.
Brake Pedal Position Switch
The brake pedal position switch signals the ECM when
the brake pedal is oressed.
Electrical Power Steering (EPS) Senser
The EPS sensor signals the ECM when the power
steering load is high.
ldle Air Control llACl Valve
To maintain the proper idle speed, the IAC valve
changes the amount of air bypassing the throttle body
in response to an electrical signal from the ECM.
From AIR To INTAKECLEANER MANIFOLD
IAC VALVE
11-32
Fuel Supply System
Fuel Cut-off Control
During deceleration with the throttle valve closed,
current to the injectors is cut off to improve fuel
economy at engine speeds over 1,030 rpm. Fuel cut-off
action also occurs when engine speed exceeds
6,900 rpm, regardless of the position of the throttle
valve, to protect the engine from over-rewing. When
the vehicle is stopped. the ECM cuts the fuel at engine
speeds over 6,500 rpm.
Fuel Pump Control
When the ignition is turned on, the ECM grounds the
PGM-Fl main relay which feeds current to the fuel pump
for 2 seconds to pressurize the fuel system, With the
engine running. the ECM grounds the PGM-Fl main
relay and feeds current to the fuel pump. When the
engine is not running and the ignition is on, the ECI\4
cuts ground to the PGM-Fl main relay which cuts
current to the fuel pump.
PGM-FI Main Relay 1 and 2
The PGM-Fl main relay consists of two separate relays.
Relay 1 is energized whenever the ignition switch is ON(ll) to supply battery voltage to the ECM power to the
injectors, and power for relay, Relay 2 is energized to
supply power to the fuel pump for 2 seconds when the
ignition switch is turned ON (ll), and when the engine is
runnrng.

""rr"a* JIr''lHr/cnN 1
CONNECTOR E
CONNECTOi K
CONNECTOFJ/GRN
IGNITIONSWITCH
lG2
'I
TESTTACHOMETERCONNECTO8
UNDER.HOOD
UNDER.DASHFUSE/RELAY BOX:
UNDER.DASHFUSE/FELAY BOX
Brake pedal pressed: closedBrake pedal releasedr open
POStTtON SWTTCH
,or"-9J3{51re* _{F "_.rl
4 ACG (1oAt1 tGN CO|L t15A)2 A/F HEATER {2OA)17 FUEL PUMP I15A}1O METER {7.5AI14 A/C CLUTCH RELAY {1OA}
11-45

PGM-FI System
DTC Troubleshooting (cont'dl
DTC P0171: Fuel System Too Lean
DTC P0172: Fuel System Too Rich
NOTE: lf some of the DTCS listed below are stored at
the same time as DfC PO17'l and/ot PO172,
troubleshoot those DTCS first, then recheck for P0171
andlot P0112.
P0107, P0108. P1 128. P1 129: Manifold absolute
pressure (MAP) sensor
P1 162. P1 166, P 1 167: 4,,/F sensor (Sensor 1 ) heater
P0137, P0138: Secondary HO2S (Sensor 2)
P014'l: Secondary HO2S (Sensor 2) heater
P1259: VTEC system
1. Check the fuel pressure (see page 11-'145).
ls luel pressure OK?
YES Go to step 2.
NO Check these items:
. lf the pressure is too high, replace the fuel
pressure regulator (see page 11-152).1. lf the pressure istoo low.checkthefuel pump,
the fuel feed pipe, the fuel filter, and replace the
fuel pressure regulator (see page 11-152).I
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
11-70
3. Turn the ignition switch OFF.
4. With a vacuum pump, apply vacuum to the
evaporative emission (EVAP) canister purge valve
(A) from the evaporative emission (EVAP) canister
side.
' A973AX-041-XXXXX
Does it hold vacuum?
YES-Check the engine valve clearances and adjust
if necessary, lf the valve clearances are OK, replace
the injectors (see page 1 1-1 1 1).1
NO-Replace the EVAP canister purge valve.l

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