2003 HONDA CIVIC o2 sensor

Fuel and Emissions Systems
Knock Sensor Circuit N4alfunction
Crankshaft Position (CKP) Sensor Intermittent(see page 11-78)
(see oaqe 11-121
PO4i{
TU45I
P0452
Camshaft Position (CMP) Sensor A Intermiftentisee page 11-121)
Yetrgb-le Velye TiTing _controlll/T!) Phqse Gsee oaoe 11-122
CqJalyst System Elficie-ncy Below Thresholdsee oaqe 1 1- 167
Fuel Tank Pressure (FTP) Sensor Range/Performance (seepagell 171)
Sensor Circuit Low V11-172
Fuel Tank Pressure (FTP) Sensor Circuit High V
Vehicle SDeed SensorCircuit Malf unction
Camshaft Position (CMP) Sensor A No
P0451 (91)
see Daqe 11-130)
(see page 1 1-81)
Refer to the l\4ultiplex
Control System
Troubleshooting {see
(see page 1 1-83)
(see paSe 1 1'83)
Barometric Pressure (BARO) Sensor Circuit High{see page 11-83)
P't 121
Pl122
P11f,.8
Throttle Position {TPi Sensor Signal Lower Than(see page 11-63)
-tsee page I r-oJ,
G;tp"s" 1 154)
(*" paSe 1 154)
P1122 ll J
ij1128 (5)
Throttle Position (TP) Sensor Signal Higher Than
Mani{old Absolute Pressure (l\,4AP} Sensor Signal
Loqer Tha n Expected
Manifold Absolute Preisure (MAP) SeiiioiSgnul
Hiqher Than Ex(see page 11-84)
Engine Control Module (ECN4) Power Source Circuil
Serial Communication Link Malfunction
P1106 (13)
P110? (13
P1 108 (ts'
Barometric Pressure (BARO) Sensor Range/
Performance Problem
Barometric Pressure (BARO) Sensor Circuit Low
P1121 11)
P1 129 (5)
P1157 (48)
Pr 158 (48)
Air Fuel Ratio (AVF) Sensor (Sensor 1) Range/
Rerformance Problem
AirFuel Ratio{A"F) Sensor {Sensor 1)AFS Terminal(see page 1 1-85)
Air Fuel Ratio 1AVF) Sensor isensor 'l) AFS + Terminal(see page 1 1-86)
Air Fuel Ratio {A,/F) Sensor {Sensor I ) Slow Response
Air Fuel Ratio (A/F) Sensor (Sensor 1) Range/(see page 1 1-88)
Air Fuel Ratio (4,/F) Sensor (Sensor 1) Heater Circuit
Malfunction
(see page 11-89)
Air Fuel Ratio (A,/F) Sensor (Sensor 1) Heater System
Malfunction
(see page 11-91)
P1 159 (48)
P1163 (61
P1164 (61)
P1 166 (41)
P1 167 (41) '
DTC Troubleshooting Index (cont'd)
" :These DTCS are indicated by a blinking MIL when the SCS servlce signal line is jumped with the Honda PGM
Tester.* 1r '02 model
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11-8
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(
a

DTC
{MlL indication*l
Temporary DTCDetection ltemPage
P1259 t22JVTEC System l\4alfunction(see Daqe 11-123)P1291 t20\Electrical Load Detector (ELD) Circuit Low Voltaqe(see Daqe l1-92)P1298 (20)Electrical Load Detector (ELD) Circuit Hiqh Voltaqe(see oaoe 11-93)P1361 (8)Camshaft Position (CMP) Sensor B (Top Dead Center(TDC) Sensor) Intermittent Sional InterruDtion
(see page 11-95)
P1362 (8)Camshaft Position (CMP) Sensor B (Top Dead Center(TDC) Sensor) No Siqnal
(see page 11-95)
P'r456 (90)P1456Evaporative Emissions (EVAP) Control System
Leakaqe (Fuel Tank Svstem)
(see page 11-175)
P14s7 (90)P1457Evaporative Emissions (EVAP) Control System
Leakaqe (EVAP Canister Svstem)
(see page 1'l-180)
P1505 (109)P1505Positive Crankcase Ventilation (PCV) Air Leakaqe(see oaqe 11-1681
P1519 (14)ldle Air Control (lAC) Valve Circuit Malfunction{see paqe 11-131)P1607 ( )Engine Control Module (ECM) Internal Circuit
Malfunction
(see page 1 1-96)
" : These DTCS are indicated by a blinking MIL when the SCS service signal line is jumped with the Honda PGM
Tester.
11-9

Fuel and Emissions Systems
Symptom Troubleshooting Index
When the vehicle has one of these symptoms, check the diagnostic trouble code (DTC) with the scan tool. lf there is no
DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.
SvmotomDiaqnostic procedureAlso check lor
Engine will not sta rt
(MlL works OK, no DTCS set)
1. Test the battery {see page 22-50).
2. Test the starter (see page 4-8).
3. Troubleshoot the fuel pump circult (see page 11
141).
Low compressron
No ignition spark
lntake air leaks
Locked up engine
Broken timing chain
Contaminated fuel
Engine will not start (MlL
comes on and stays on, or
never comes on at all, no
DTCS set)
Troubleshoot the l\4lL circuit (see page 1 '1-97).
Engine will not start
(immobilizer indicator stays
on or flashs)
Troubleshoot the immobilizer system (see page 22-165).
Hard starting(MlL works OK, no DTCS set)
1. Testthe battery (see page 22-50).
2. Checkthe fuel pressure (see page 11-145).
Low compression
Intake air leaks
Contaminated fuel
Cold fast idle too low(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure (see page 11-139).
2. Checkthe idle sDeed (see paqe 11-138).
Cold fast idle too high
(MlL works OK, no DTCS set)
Do the ECI\4 idle learn procedure (see page 1 1- 139).
Checkthe idle speed {see page 11-138).
Inspect/adjust the throttle cable (see page 1 '1-'163).
Inspect and test the throttle body {see page 1 1-160}.
']
2.
3.
ldle speed fluctuates
(MlL works OK, no DTCS set)
1. Dothe ECM idle learn procedure (see page 11-'139).
2. Check the idle speed (see page 11-138).
3, Inspecvadjust th e throttle cable (see page 11''163).
4. Insoect and test the throttle bodv (see paqe 11- 160)
Intake air leaks
After warming up, idle speed
is below specifications with
no load
{MlL works OK, no DTCS set)
1. Do the ECIVI idle learn procedure (see page 1 1- 139).
2. Troubleshootthe alternator FR signal circuit (see
page 11-'134).
3. InsDect and test the throttle bodv {see paqe 1 1-160).
Vacuum hose clogged/
cracked/poor
connectron
After warming up, idle speed
is above specifications with
no toao(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure {see page 1'j-139).
2. Troubleshoot the alternator FR signal circuit(see
page 11-134).
Low power
(MlL works OK, no DTCS set)
1. Check the fuel pressure(seepagell-145).
2. Inspect and test the th roftle body (see page 11-160).
3. Inspecvadjust the throttle cable (see page 11-'163).
Low compressron
Camshaft timing
problem
Engine oil levelprootem
Engine stalls(MlL works OK. no DTCS set)
1. Do the ECM idle learn procedure (see page 1'l'139).
2. Check the fuel pressure{seepagell-145).
3. Check the idle speed (see page I 1-138).
4. Troubleshootthe brake pedal position switch signal
circuit (see paqe 11-137).
lntake air leaks
Faulty harness and
sensor connections
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11-10
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Fuel and Emissions Systems
System Descriptions
Electronic Control System
The functions of the fuel and emlssion control systems are managed by the engine control module (ECM).
Fail-safe Function
When an abnormality occurs in the signal from a sensor, the ECI\4 ignores that signal and assumes a pre-programmed
value for that sensor that allows the enqine to continue to run.
Back-up Function
When an abnormality occurs in the ECM, the injectors are controlled by a back-up circuit independent of the system to
permit minimal driving.
Self-diagnosis
When an abnormality occurs in the signal from a sensor, the ECM supplies ground for the malfunction indicator lamp
{MlL) and stores the diagnostic trouble code {DTC) in erasable memory. When the ignition is first turned on, the EClvl
supplies ground to the l\4lL for 15 to 20 seconds to check the M lL bulb condition.
Two Driving Cycle Detection Method
To prevent false indications, the "two driving cycle detection method" is used for some self-diagnostic functions.
When an abnormality occurs, the ECM stores it in its memory. When the same abnormality recurs afterthe ignition
switch is turned OFF and ON (ll) again, the ECM turns on the MlL.
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11-12
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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
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ra

Fuel and Emissions Systems
aSystem Descriptions (cont'dl
ECM Electrical Connections
\
No. INJECTOR
No,2INJECTOR
No.3 INJEC]OB
No./tINJECTOF
MAPSENSON
TPSENSOR
IATSENSOR
ECTSENSOB
\'
CMP SENSOR B(TDC SENSOSJ
CKPSENSOR
11-16
F€VERSE LOCKSOLENOIDVAIVE
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EVAPCANISTE6PURGE VAIVE
EVAPCANISTERVENTSHUTVATVE
sotENotovAtvE
A/FSENSOR
A/FSENSOR(sENSOn 1)
CMP SENSOF A
VIC OIL CONTROLSO!ENOIDVALVE
wEcorlPRESSUSE SWTICH
VTEC SOLENOID
{cont'd)
11-17
No. 1 IGNITION COIL
No.2lGNlllON COIL
No. 3 IGNITION COIL
No. a IGNITION COIL