oxygen HONDA CIVIC 2003 7.G Workshop Manual

18.
19.
Remove the drive belt (see page 4-26).
Remove the lvC line mounting bolt.
20. Remove the radiator cap.
21. Raise the hoist to full height.
22. Remove the front tires/wheels.
23. Remove the splash shield.
o@
24. Loosen the drain plug in the radiatorto drain the
engine coolant (see page 10-6).
25. Drain the transmission fluid (see page 13'3).
26. Drain the engine oil {see page 8-5).
27. Disconnect the stabilizer links (see page 18-18).
28. Disconnect the suspension lower arm ball joints
(see step 3 on page 18-19).
29. Remove the driveshafts {see page 16-3). Coat all
precision finished surfaces with clean engine oil.
Tie plastic bags over the driveshaft ends.
30. Disconnect the air fuel ratio {4,/F) sensor connector
(A) and secondary heated oxygen sensor
(secondary HO2S) connector (B), then remove the
three way catalytic converter {TWC) assembly {C).
31. Remove the lower hose.
(cont'd)
5-5

Engine Assembly
18.
Engine Installation {cont'dl
10 x 1.25 mm33 N.m {3.i1kgf.m,25 tbt.ftl
19.
20.
Connect the suspension lower arm ball joints (see
step 6 on page 18-19).
Connect the stabilizer links (see page 18-18).
Install the three way catalytic converter (TWC)
assembly (A); use new gaskets (B) and new self-
locking nuts {C).
\D
21.
-d
,ry6\
8 x 1.25 mm22N.m |.2.2kgl m,16 tbt.ft)
Connect the air fuel ratio (4,/F) sensor connector (D)
and secondary heated oxygen sensor (secondary
HO2S) connector (E).
Install the lower radiator hose.
5-12
va
23. Installthe splash shield.
24.
25.
26.
Lower the hoist.
Installthe drive belt.
Installthe A,/C line mounting bolt.
6 x '!.0 mm9.8 N.m (1.0 kgf.m,7.2 tbt.ftl
. -t- --- ----r

lntake Manifold and Exhaust System
Exhaust Pipe and Muffler Replacement
SELF-LOCKING NUT10 x 1.25 mm33 N.m {3.4 kgf.m,25 rbf.ft)Beplace.
8 x 1.25 mm22 N.m {2.2 kgf m, 16lbf.ft)Replace.Tighten the bolts in steps,alternating side to-side.
\
NOTE: Use new gaskets and self-locking nuts when reassembling.
8 x 1.25 mm22 N.m (2.2 kst.m. 16lbf.ftlReplace.Tighten the bolts in steps,alternating side'to side.
EXHAUST PIPE B
HEAT SHIELD\,
6x1.0mm9.8 N.m{1.0 kgt.m, 7.2 lbf ft}
GASKETReplace.
SECONDARY HEATEDOXYGEN SENSOR{SECONDARY HO2SIil4Nm(4.5 ksf.m,33 lbf.ftl
AIR FUEL RATIO {A/F)SENSOR44 N.m (it.s kgf.m, 33 lbf ftl
9-8
\-.

DTC Troubleshooting Index
";These DTCs are indicated by a blinking malfunction indicator lamp (MlL)when the SCS service signal line isjumped with the Honda PGM Tester.
{cont'd)
11-7
DTC
{MlL indication*)
Temporary DTCDetection ltemNote
P0010 (56)Variable Valve Timing Control {VTC) Oil Control
Solenoid Valve Malfunction
{see page 1 1'1 18)
P0011 (56)P001 1Variable Valve Timing Control (WC) System
Malfunction
(see page 11- 1 19)
P0107 (3)Manifold Absolute Pressure (MAP) Sensor Circuit
Low Voltaqe
(see page 1'l-521
P0108 (3)Manifold Absolute Pressure (MAP) Sensor Circuit
Hiqh Voltaqe
(see page 11-53)
P0112 (10)Intake Air Temperature (lAT) Sensor Circuit Low
Voltaoe
(see page 11-55)
P01r3 (10)Intake Air Temperature (lAT) Sensor Circuit High
Voltaoe
(see page '11-56)
P0116 {86) P0116Englne Coolant Temperature (ECT) Sensor Range/
Performance Problem
{see page 11-57)
P0117 {6)Engine Coolant Temperature (ECT) Sensor Circuit
Low Voltaqe
(see page 11-58)
P0118 {6)Engine Coolant Temperature (ECT) Sensor Circuit
Hiqh Voltaqe
{see page 11-59)
P0122 t7\Throttle Position (TP) Sensor Circuit Low Voltaqe(see Daqe 11-60)P0123 {7)Throttle Posltion (TP) Sensor Circuit Hiqh Voltaoe(see paqe 11-62)
P0128 (87)P0128Coolinq SVStem Malfunction(see Daqe 11-64)
P0134 (41)Air Fuel Ratio (Ay'F) Sensor (Sensor 1) No Activity
Detected
(see page 11-65)
P0137 (63)P0137Secondary Heated Oxygen Sensor (Secondary HO2S)(Sensor 2) Circuit Low Voltaqe
(see page 11-65)
P0138 (63)P0138Secondary Heated Oxygen Sensor (Secondary HO2S)(Sensor 2) Circuit Hiqh Voltaqe
(see page 11-66)
P0139 (63)P0139Secondary Heated Oxygen Sensor (Secondary H02S)(Sensor 2) Slow ResDonse
(see page 11-67)
P0141 (65)Secondary Heated Oxygen Sensor (Secondary H02S)(Sensor 2) Heater Circuit Malfunction
(see page 11-68)
P0171 (45)PO\11Fuel Svstem Too Lean(see paqe 11-70)
PO112 l'45)PO\l2Fuel System Too Rich(see oaoe 11-70)
P0300 and any P0300 and any
of of
P0301 (71) P0301
PO302 (721 P0302
P0303 (73) P0303
P0304 (74) P0304
Random Misfire(see page 11-71)
P0301 (7'1) P0301No. 1 Cylnder Misfire{see page 11-72)
P0302 (721 P0302No. 2 Cvlnder Misfire{see paqe 1 1-72)
P0303 (73)P0303No. 3 Cvlnder Misfire(see oaqe 11-72)
P0304 {74)P0304No. 4 Cvlnder Misfire{see Daqe 1 1-72)

ECM Data
You can retrieve data from the ECI\4 by connecting the OBD ll scan tool or the Honda PGM Tester to the data link
connector (DLC). The items listed in the table below conform to SAE recommended practice. The Honda PGM Tester
also reads data beyond that recommended by SAE to help you find the causes of intermittent problems.
The "operating values" listed are approximate and may vary depending on the environment and the individual
vehicle.
Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up in the neutral position,
and the A,/C and all
Diagnostic
Trouble Code(DTC}
lf the ECM delects a problem, it will store it as a code
consisting of one letter and four numbers. Depending on
the problem, an SAE-defined code (Poxxx) or a Honda,
defined code {P1xxx) will be output to the tester.
The ECI\4 computes engine speed from the signals sent
from the crankshaft position (CKP) sensor. This data is
used for determining the time and amount of injected fuel.
detected, there is no
ourpul.
lf no problem is YES
Nearly the same as
tachometer indication
At idle speed;
The ECM converts pulse signals from the vehicle speed
sensor (VSS).Nearly the same as
speedometer
indication
Manifold
Absolute
Pressure(MAP)
The absolute pressure caused in the intake manifold by
engine load and speed.
With engine stopped: YES
Nearly the same as
almospnenc pressure.
At idle speed: about
20 4'1 kPa(150 310 mmHg,
6- 12 in.Hq).0.7 1.3 V
The ECT sensor converts coolant temperature into voltage
and signals the ECM. The sensor is a thermistor whose
internal resistance changes with coolant tempetature. The
ECM uses the voltage signals from the ECT sensor to
determine the amount of injected fuel.
With cold engine:
Same as ambient
temperature and IAT
With engine warmed
up; about 116 2'12"F
100'c).0.5-0.8 v
Air Fuel Ratio The A,/F sensor detects the oxygen content in the exha ust 0.0 - 1 .25 V(Ay'F) Sensor. gas and sends voltage signals to the Eclvl, Basedonthese 8.0 11.0mA(PGM(Sensor 1) signals, the ECM controls the airlfuel ratio. When the I Tester)
oxygen content is high (that is, when the ratio is leaner At idle speed:
than the stoichiometric ratio), the voltage signal is Iower. about 0.1 0.9 V
When the oxygen content is low (that is, when the ralio is
richer than the stoichiometric ratio). the voltage signal is
higher. The A'lF sensor signals are electrical current that
are indicated as voltaqe on the
The HO2S detects the oxygen content in the exhaust gas
and sends voltage signals to the ECM. Based on these
signals, the ECM controls the airlfuel ratio. When the
oxygen content is high (that is, when the ratio is leaner
than the stoichiometric ratio), the voltage signal is lower.
When the oxygen content is low (that is, when the ratio is
richer than the stoichiometric ratio), the voltage signal is
Secondary
Heated
Oxygen
Sensor(Secondary
H02S,
Sensor2)
0.0 1.25 V NO
At idle speed:
about 0.1 0.9 V
(cont'd)
11-13

Fuel and Emissions Systems
System Descriptions (cont'd)
ECM Data (cont'd)
w
DataDescriptionOpera'ting ValueFreeze Data
Fuel System
Status
Fuel system status is indicated as "open" or "closed".
Closed: Based on the A,/F Sensor output, the ECM
determines the airlfuel ratio and controls the amount of
injected fuel.
Open: lgnoring Ay'F Sensor output, the ECM refers to
signals from the throttle position {TP), manifold absolute
pressure (MAP), intake air temperature (lAT), barometric
pressure (BARO), and engine coolant temperature (ECT))
sensors to control the amount of iniected fuel.
At idle speed: closedYES
Short Term
FuelTrim
The airlfuel ratio correction coefficient for correcting the
amount of injected fuel when the fuel system status
is "closed." When the ratio is leaner than the
sloichiometric ratio, the ECM increases short term fuel
trim gradually, and the amount of iniected fuel increases.
The airlfuel ratio gradually gets richer, causing a lower
oxygen content in the exhaust gas. Consequently, the
short term fuel trim is lowered, and the ECM reduces the
amount of injected fuel.
This cvcle keeps the airlfuel ratio close to the
stoichiometric ratio when in closed loop status.
o.7 1.5YES
Long Term
Fuel Trim
Long term fuel trim is computed from short term fuel trim
and indicates changes occurring in the fuel supply system
over a long period.
lf long term fuel trlm is higher than 1.00, the amounl of
injected fuel must be increased. lf it is lower than 1.00, the
amount of injected fuel must be reduced.
0.8 1.2YES
Intake Air
Temperature
{IAT)
The IAT sensor converts intake air temperature into
voltage and signals the ECM. When intake air
temperature is low, the internal resistance ofthe sensor
increases, and the voltage signal is higher.
With cold engine:
Same as ambient
temperature and ECT
YES
Throttle
Position
Based on the accelerator pedal position, the opening
anole of the throttle valve is indicated.
At idle speed:
about 10 %
YES
lgnition
Timing
lgnition timing is the ignition advance angle set by the
ECM. The ECM matches ignition timing to driving
conditions.
At idle speed: 8" t 5"
|' tuL wnen rne >L)
service signal line is
jumped with the Honda
PGM Tester
NO
Calculated
Load Value
(cLV)
cLV is the enoine load calculated from IMAP data.At idle speed:
12 34%
At 2.500 rpm with no
toao:'t4- 34%
YES
11-14
\.,
ra

Fuel and Emissions Systems
System Descriptions (cont'dl
ECM lnputs and Outputs at Connector E (31P}
L
u
1iMoFPR
2sr-{]zs3LG34SG3
6$1025HTC
1M RLY
8AFSHTCR
I
14FTP15ELD
16EPSLD
18ACC20Z/VBS21VSV
22BKSW23K-LINE24SEFMJ26NEP
21rMoCD
29scs30WEN31MIL
Wire side of female terminals
NOTE: Standard battery voltage is '12 V.
TerminalnumberWire colorferminal nameDescription Signal
GRNI/ELIMO FPR (IMMOBILIZERFLJEL PUMP RELAYIDrives PGM Fl main relay 20Vfor2 seconds after turning ignition switch ON{ll). then batterv voltaoe2WHT/REDSHO2S (SECONDARYHEATED OXYGEN SENSOR(SECONDARY HO2S),SENSOR 2r
Detects secondary HO2S{sensor 2) signalWith throttle Jully opened from idle with fullywarmed up engine: above 0.6VWith throttle quickly closed: below 0.4 V
3BRN/YELLG3 (LOGIC GROUND)cround forthe ECM/PCMcontrolcircuitLess than 1.0 V at all times
4PNKSG3 {SENSOR GBOUND)Sensor oroundLess than 1.0 V at all times5YEUELUVCC3 {SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (ll): about 5 VWith ionition switch OFF: about 0 V6BLKATr'HTSO25HTC (SECONDARYHEATED OXYGEN SENSOR(SECONDARY H02S)HEATER CONTROL)
Drives secondary HO2SheaterWith ignition switch ON (ll): baftery voltageWilh fullv warmed up engine running: dul,controlled
1REDA/ELMRLY (PGM.FI MAINRELAY}Drives PGM-Flmain relay 1Power source forthe DTCWith ignition switch ON (ll): about 0 VWith ignition switch OFF: battery voltage
IORNAFSHTCR {AIR FUEL BATIO(Iy'F)SENSOR HEATERCONTROL RELAY)
Drives air fuel ratio sensorheater relayWith ignition swirch ON {ll): 0 V
IYEUBLKIGl (IGNITION SIGNAL)Detecrs ignition signalWith ignition switch ON (ll): battery voltageWith iqnition switch OFF: about 0 V't4LT GRNFIP lFUEL TANKPRESSURE (FTP) SENSOR)Detects FTP sensor signalWith ignition switch ON (ll) and fuel fill cap open:about 2.5 VGRN/REDELD (ELECTRICAL LOADDETECTOF)Detects ELD signalWith ignition swjtch ON itt):aOoutO.t V l-gV(deDendino on electrical load)LT GRN/8LKEPSLD (ELECIRICALPOWEB STEEBING LOADDETECT)
Detects Power steering loadsrgnalAt idle with steering wheel in straight aheadposition: about 0 VAt idle with steering wheelatfull lock: momentary
'18REDACC (Ay'C CLUTCH RELAY)Drives P,/C clutch relayWith compressor ON: about 0 VWith comoressor OFF: batterv voltaoe
11-22
\-

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

Fuel and Emissions Systems
(
(
(
System Descriptions (cont'dl
Secondary Heated Oxygen Sensor (Secondary HO2S)
The secondary HO2S detects the oxygen content in the
exhaust gas downstream of the three way catalytic
converter (TWC) and sends signals to the ECM which
checks the efficiency of the TWC. To stabilize its output,
the sensor has an internal heater. The secondarv HO2S
is installed in the TWC.
ztRcoNtaELEMENTSENSORTERMINALS
HEATERTERMINALS
Starting Control
When the engine is started, the ECM provides a rich
mixture by increasing injector duration.
Throttle Position ITP) Sensor
The TP sensor is a potentiometer connected to the
throttle valve shaft. As the throttle position changes, the
sensor varies the signal voltage to the ECM. The TP
sensor is not replaceable apart from the throftle body.
ELEMENTBRUSH HOLDER
gRUSH
11-28
Vehicle Speed Sensor (VSS)
The VSS is driven by the differential. lt generates apulsed signal from an input of 5 volts. The number ofpulses per minute increases/decreases with the speed
of the vehicle.
BEARING

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