2003 HONDA CIVIC o2 sensor

VTEC/VTC
10.
DTC Troubleshooting (cont'd)
Measure voltage between ECM connector terminal
A25 and body ground.
ECM CONNECTOR A 131P)
Wire side of female te.minals
ls there about 5 V?
YES-Repair open in the wire between the ECM(A25) and CMP sensor A.I
NO-Go to step 11.
Turn the ignition switch OFF.
Disconnect ECM connector A (31P)
Check for continuity between ECM connecror
terminal A25 and body ground.
ECM CONNECTON A 131P}
Wire side of femaleterminals
ls tnere continuity?
YES-Repair short in the wire between the ECM(A25) and the CMP sensor A. t
NO Update the ECt\4 if it does not have the latest
software, or substitute a known-good ECM, thenrecheck (see page 1 1-6). lf the symptom/indicationgoes away with a known-good ECM, replace the
original ECM.I
11.
't2.
11-122
DTC P0341: WC Phase Gap
1. Resetthe ECM {see page 11-4).
2. Start the engine.
ls DTC P0341 indicated?
YES Go to step 3.
NO Intermittent failure, system is OK at this time.Check for poor connections or loose terminals atthe CMP sensor A and at the ECM.I
3. Check the VTC oil control solenoid valve (see page
11_127]-.
Isthe VTC oil control solenoid valve OK?
YES-Go to step 4.
NO-CIean the VTC oil control solenoid valve, orreplace it (see page 11-'l27l.a
4. Remove the head cover, and check the cam chain
{see page 6-12).
ls the cam chain OK?
YES Go to slep 5.
NO Replace the cam chain (see page 6-12).1
5. Check the VTC actuator (see page 6-8).
ls the VTC actuator OK?
YES- U pdate the ECM if it does not have the tatest
soflware, or substitute a known-good ECI\4, thenrecheck (see page 11-6). lf the symptom/indicationgoes away with a known-good ECM, replace the
original ECM.I
NO- Replace the VTC actuator.l

VTEC/WC
1.
CMP Sensor A Replacement
Remove the air cleaner (see page 1 1-162).
Disconnect the CMP sensor A 3P connector.
Remove the CMP sensor A (A).
Installthe sensor in the reverse order of removal
with a new o-ring (B).
B-'-----'-l:,",14*
11-128
WEC Solenoid Valve Removal/
Inspection
1.Disconnect the VTEC solenoid valve 2P connector.
Measure resistance between VTEC solenoid valve
connector terminals No. 1 and No. 2.
Resistance: 14-30 Q
3. lf the resistance is within specifications, remove the
VTEC solenoid valve assemblv (A)from the
cylinder head, and check the VTEC solenoid valve
filter (B)for clogging. lf it is clogged, replace the
solenoid valve filter, the engine oilfilter, and the
engine oil.
6x1.0mm9.8 N.m (1.0 kgf.m, 7,2 lbf.ftl
L

Throttle Body Removal/lnstallation
NOTE:' Do not adjust the throttle stop screw.. Afterreassembly,adjustthethrottlecable{seepagell-163) and the cruise control cable (see page 4-45).. The throttle position (TP) sensor is not removable.
THROTTLELEVER
There should beno clearance
THROTTLE CABLE
MANIFOLDABSOLUTE PRESSURE{MAP} SENSOR
22Nm(2.2 kgt.m, 16 lbf.ft)
EVAPORATIVE EMISSION {EVAPICANISTER PURGE VALVE
IDLE AIR CONTROL{IACI VALVE
11-165

Intake Air System
Throttle Body Disassembly/Reassembly
EVAPORATIVE EMISSION {EVAP)CANISTER PURGE VALVE
A
V
2 N.m{0.2 kgt m, 1 lbf.ft)
3.5 N.m(0.35 kgf m.2.5lbf ft)
MAP SENSOR
THROTTLE BODY
L
TP SENSOR
11-166

Catalytic Converter System
DTC Troubleshooting
DTC P0420: Catalytic System Efficiency
Below Threshold
NOTE: lf some of the DTCS listed below are stored at
the same time as DTC P0420, troubleshoot those DTCS
first, then recheck for DTC P0420.
P0137, P0138: Secondary Heated Oxygen Sensor(secondary HO2S) (Sensor 2)
P0141: Secondary HO2S (Sensor 2) heater
1. Reset the ECM {see page 1'l-4}, then continue to
step 2 through 5 to reset the readiness code.
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) untilthe radiator fan comes on.
Drive for about l0 minutes without stopping. Your
speeo can vary.
With the transmission in 4th gear, drive at a steady
speed between 50 62 mph (80-'100 km/h) for
30 seconds.
Repeat step 4 three times. Between each repetition,
close the throttle completely for 1 2 seconds. lf
the engine is stopped during this part of the
procedure, repeat steps 3, 4 and 5.
Check for a Temporary DTC with the scan tool.
Does the scan tool indicate Temporaty DTC
P0420?
YES Check the TWC. lf necessary, replace the
TWC.I
NO Check for readiness code completion. lfthe
readiness is complete, it was a interminent failure,
and the system is OK at this time. lf the readiness
code is incomplete, repeat steps 2 through 5.1
4.
11-167

EVAP System
Component Location Index
EVAPORATIVE EMISSION {EVAP)CANISTER VENT SHUT VALVETroubleshooting,step 23 on page 1'l 178,step 1g on page l1- 182
EVAPORATIVE EMISSION IEVAPICANISTER PURGE VALVETroubleshooting,step 3 on page 'l1-175,
step 1on page 11-180
FUEL TANK VAPOR CONTROL VALVETest, page 11'187Replacement, page 11 189
FUEL TANK PRESSURE SENSORTroubleshooting, page 1 1-171
EVAPORATIVE EMISSION {EVAPICANISTERTroubleshooting, step 28 on page 11'183Replacement, page 1 1-189
EVAPORATIVE EMISSION {EVAP}BYPASS SOLENOID VALVETroubleshooting,step 12 on page '11'176,
step '10 on page 11 181
EVAPOBATIVE EMISSON {EVAP)TWO WAY VALVETest, page 'l1-'186
11-170

DTC Troubleshooting
DTC P0451: FTP Sensor Range/Performa nce
Problem
Special Tools Required
Vacuum Pump/Gauge, 0-30 in. Hg A973X-041-XXXXX
1. Remove the fuel fill cap.
2. Turn the ignition switch ON (ll)
3. l\4onitor fuel tank pressure (FTP) sensorvoltage
with the Honda PGM Tester, or medsure voltage
between ECM connectorterminals E4 and E14.
ECM CONNECTOR E 131P)
Wire side of female terminals
ls there about 2.5V?
YES-Go to step 4.
NO Replace the FTP sensor.I
Turn the ignition switch OFF.
Disconnect the hose between the EVAP two way
valve and the FTP sensor at the EVAP two way
valve end.
4.
5.
7.
8.
6. Connect a vacuum pump to the open end of the
hose.
Turn the ignition switch ON {ll).
l\4onitor FTP sensor voltage with the Honds PGM
Tester, or measure voltage between ECM
connector terminals E4 and E14, and carefully
squeeze the vacuum pump a little.
ECM CONNECTOR E 13lPI
Wire side of lemale terminals
The voltage should smoothly drop from about 2.5 V
to about 1.5 V. Stop applying vacuum when the
voltage drops to about 1.5 V or damage to the FTP
sensor may occur.
Does the voltage drop to about 1.5 V and hold?
YES Check for misrouted, leaking, or broken FTP
sensor vacuum lines. lf the vacuum lines are OK,
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
NO Replace the FTP sensor. !
9.
11-171

EVAP System
DTC Troubleshooting (cont'd)
DTC P0452: FTP Sensor Circuit Low Voltage
1. Check the vacuum lines at the FTP sensor for
misrouting, leakage. breakage, or clogging.
Are the vacuum lines OK?
YES Go to step 2.
NO Repair or replace vacuum lines as
necessary. I
2. Reset the ECM (see page 11-4).
3. Remove the fuelfill cap.
4. Turn the ignition switch ON (ll)
5. Monitor FTP sensor voltage with the Honda PGM
Tester, or measure voltage between body ground
and ECM connector terminal E14.
ECM CONNECTOR E 131PI
1 2t3t45o/89
././114tc61./182C21
22123241 t26271/ 2931
TP (LT GRN)
Wire side of female terminals
ls thete about 2.5 V?
YES- Intermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the FTP sensor and at the ECrM.l
NO Go to step 6.
11-172
6. Turn the ignition switch OFF.
7. Reinstallthe fuel fill cap.
8. Disconnect the FTP sensor 3P connector.
9. Turn the ignition switch ON (ll)
10. Measure voltage between FTP sensor 3P connector
terminals No. 1 and No.2.
FUEL TANK PRESSURE SENSOR 3P CONNECTOR
VCgl {YEL/BLU}
Wire side of female terminals
ls there about 5 V?
YES Go to step 1 '1.
NO-Repair open in the wire between the FTP
sensor and the ECM {E5).1