code HONDA CIVIC 2003 7.G Owner's Manual

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.
\
11-12
\.
\{

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

ECM Inputs and Outputs at Connector E (31P)
ltMoFPR
2$.c2s
i6SFIO2SHTC
1
IV RLY
IAFSHTCR
9tGl
14FTP15ELD
16EPSLD
t8202,4/BS21VSV
22BKSW23K LINE24SEFMJ26NEP
21lvoCD
29scs30WEN31MIL
Wire side of female terminals
NOTE: Standard battery voltage is 12 V.
TerminalWire colorTerminalnameDescriptionSignal
20BLU/RED2WBS (EVAPORATIVEEMISSION (EVAP)BYPASSSOLENOID VALVE)
Drives EVAP bypass With ignition switch ON (ll): baftery voltagesolenoid valve
21LT GRN/REDVSV (EVAPORATIVE
EI\4ISSION iEVAP)CANISTEB VENT SHUTVALVE)
Drives EVAP canister ventshut valveWith ignilion switch ON (ll): battery voltage
22WHT/BLKBKSW lBRAKE PEDALPOSITION SWITCH)Detects brake pedaloosition switch sionalWith brake pedal released: about 0 VWith hrake nedal nresse.l: batterv voltaoe23LT BLUK-LIN ESends and receives scanWith ignition switch ON (li)r pulses or battery
YELSEFMJCommunicates withmrltinleY eontrol unitWith ignition switch ON (ll): about 5 VWith enoine runnino under load: DUlses26BLUNEP (ENGINE SPEEDPULSE)Outputs engine speed pulseWith engine running: pulses
21RED/BLU \40CD fl\4MOBTLTZERCODE)Detects imrnobilizer signal
29BRNSCS (SERVICE CHECKSIGNAL)Oetects service check signalWith the service check signal shorted with the PGMTester: about 0 VWiih rhe service check sional ooened: about 5 V
30RED,A/VHTWEN (WRITE ENABLESIGNALiDetects write enable signal With ignition switch ON (ll): about 0 V
GRN/ORNMIL (MALFUNCTION
INDICATOR LAMP)Drives N4lLWith MIL turned ON: about 0 VWith MIL turned OFF: batterv voltaqe
(cont'd)
11-23

lgnition Timing Control
The ECM contains the memory for basic ignition timing
at various engine speeds and manifold absolute
pressure. lt also adjusts the timing according to engine
coolant temperature.
Iniector Timing and Duration
The ECM contains the memory for basic discharge
duration at various engine speeds and manifold
pressures. The basic discharge duration, after being
read out from the memory, is further modified by
signals sent from various sensors to obtain the final
discharge duration.
By monitoring long term fuel trim, the ECM detects long
term malfunctions in the fuel system and sets a
Diagnostic Trouble Code {DTC).
Intake Air Temperature (lAT) Sensor
The IAT sensor is a temperature dependent resistor
{thermistor). The resistance of the thermistor decreases
as the intake air temDerature increases.
Knock Sensor
The knock control system adjusts the ignition timing to
minimize knock.
PIEZOCERAMIC
Malfunction Indicator Lamp lMlLl Indication {ln relation
to Readiness Codes)
The vehicle has certain "readiness codes" that are part
of the on-board diagnostics for the emissions systems.
lf the vehicle's baftery has been disconnected or gone
dead. if the DTCS have been cleared, or if the ECM has
been reset. these codes are set to incomplete. In some
states, part of the emissions testing is to make sure
these codes are set to comDlete. lf all of them are not
set to complete, the vehicle may fail the test and the
test cannot be finished.
To check if the readiness codes are set to complete,
turn the ignition switch ON (ll). but do not start the
engine.TheMILwill comeonforlS 20seconds. lf it
then goes off, the readiness codes are set to complete,
lf it blinks severaltimes, one or more readiness codes
are not set to comolete. To set each code, drive the
vehicle or run the engine as described in the
procedures to set them in this section (see page 1 1-46).
Manifold Absolute Pressure {MAP) Senso]
The MAP sensor converts manifold absolute pressure
into electrical signals to the ECM.
SENSOR UNIT
(cont'd)
11-27

Fuel and Emissions Systems
How to Set Readiness Codes
Malfunction lndicator Lamp (MlL) Indication
(ln relation to Readiness Codesl
The vehicle has certain "readiness codes" that are part
of the on-board diagnostics for the emissions systems.
lf the vehicle's battery has been disconnected or gone
dead, if the DTCS have been cleared, or if the ECM has
been reset, these codes are set to incomplete. In some
states, part of the emission testing is to make su re these
codes are set to complete. lf all of them are not set to
complete, the vehicle may fail the emission test, or the
test cannot be finished.
To check ifthe readiness codes are complete, turn the
ignition switch ON (ll), but do not start the engine. The
MIL will come on for 15 20 seconds. lf it then goes off,
the readiness codes are complete. lf it blinks several
times, one or more readiness codes are not complete.
To set readlness codes from incomplete to complete.
do the procedure for the appropriate code.
11-46
L
Catalytic Converter Monitor and Readiness
Code
NOTE:. Do not turn the ignition switch off during the
procedure.
. All readiness codes are cleared when the battery is
disconnected or when the ECM is cleared with the
OBD ll scan tool or Honda PG lvl Tester.. Low ambient temperatures or excessive slop-and-go
traffic may increase the drive time needed to switch
the readiness code from incomplete to complete.' The readiness code will not switch to com Dlete until
all the enable criteria are met.. lf a fault in the secondary HO2S system caused the
MIL to come on. the readiness code cannot be set to
comDlete until vou correct the fault.
Enable Criteria. ECT at 158"F (70'C) or higher.. Intake air temperature (lAT) at 20"F (-7'C) or higher.. Vehicle speed is steady, and vehicle speed sensor
(VSS) reads more then 25 mph (13km/h).
Procedure
1. Connect the scan tool to the vehicle's data link \
connector (DLCi, and bring up the tool's generic \"
OBD ll mode.
Start the engine.
Test-drive the vehicle under stop-and-go conditions
with short periods of steady cruise. After about
5 miles (3 km), the readiness code should switch
from incomplete to complete.
lf the readiness code is still set to incomplete, check
for a temporary DTC. lf there is no DTC, one or
more of the enable crlteria were probably not met;
2.
3.

Evaporative Emissions (EVAP) Control
System Monitor and Readiness code
NOTE:
All readiness code are cleared when the batterV is
disconnected or when the ECM is cleared with the
OBD ll scan tool or Honda PGM Tester.
The enable criteria must be repeated if the intake air
temperature (lAT) drops lower than 36'F (20"C) from
its value at engine $an up.
Enable Criteria
At engine start up, ECT and IAT are higher than 32'F(0"C) , but lower than 95'F (35"C).
At engine start up, the ECT and IAT are within 12'F(7'C) of each other.
Procedure
1. Connect the scan tool to the vehicle's data link
connector (DLC), and bring up the tool's generic
OBD ll mode.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions
with short periods of steady cruise. After about
2.5 miles (1.6 km), the readiness code should
switch f rom incomplete to complete.
4. lf the readinesscode isstill setto incomplete, check
for a temporary DTC. lf there is no DTC, one or
more of the enable criteria were probably not met;
repeat the procedure.
Air Fuel Ratio (A/Fl Sensor Monitor and
Readiness Code
NOTE:. Do not turn the ignition switch off during the
orocedure.. All readiness codes are cleared when the baftery is
disconnected or when the ECM is cleared with the
OBD ll scan tool or Honda PGM Tester.
Enable Criteria
ECT at 140'F (60"C) or higher.
Procedure
1. Connect the scan toolto the vehicle's data link
connector (DLC), and bring up the tool's generic
OBD ll mode.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions
with short periods of steady cruise. During the
drive, decelerate (wirh the throttle fully closed) for
5 seconds. After about 3.5 miles (2.2 km). the
readiness code should switch from incomDlete to
complete.
4. lfthereadinesscodeisstill set to incomplete, check
for a temporary DTC. lfthere is no DTC, the enable
criteria was probably not meU repeat the procedure.
Air/Fuel Ratio (A/Fl Sensor Heater Monitor
Readiness Code
NOTE; All readiness codes are cleared when the battery
is disconnected or when the ECM is cleared with the
OBD ll scan tool or Honda PGM Tester,
Procedure'1. Connect the scan tool to the vehicle's data link
connector {DLC), and bring up the tool's generic
OBD ll mode.
2. Start the engine, and let it idle for 1 minute. The
readiness code should switch from incomplete to
comDlete.
3. lf the readiness code is still set to incomplete, check
for a temporary DTC. lf there is no DTC, repeat theproceoure.
(cont'd)
11-47

Fuel and Emissions Systems
a
a
How to Set Readiness Codes (cont'd)
Misfire Monitor and Readiness Code
. This readiness code is always set to available
because misfiring is continuously monitored.. l\4onitoring pauses, and the misfire counter resets, if
the vehicle is driven over a rough road.. Monitoring also pauses, and the misfire counter
holds at its current value. if the throttle position
changes more than a predetermined value, or if
driving conditions fall outside the range of any
related enable criteria,
Fuel System Monitor and Readiness Code
. This readiness code is always setto available
because the fuel system is continuously monitored
during closed loop operation.. Monitoring pauses when the catalytic converter,
EVAP control system, and Ay'F sensor monitors are
active.. Monitoring also pauses when any related enable
criteria are not being met. Monitoring resumes when
lhe enable criteria is again being met.
Comprehensive Component Monitor and
Readiness Code
This readiness code is always set to available because
the comprehensive component monitor is continuously
running whenever the engine is cranking or running.
11-48
\-
L

PGM-FI System
DTC Troubleshooting (cont'dl
DTC Pl163: Ay'F Sensor (Sensor 1 ) SlowResponse
NOTE: lf DTC P1162 is stored at the same time as DTC
P1163. troubleshoot DTC P1162 first, then recheckfor
DTC P1163.
1. Reset the ECM (see page 1 1-4).
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
3. Test-drive under the following conditions:
. 55 mph (89 km/h) steady speed' Transmission in sth gear' Until the Ay'F sensor readiness code or
Temporary DTC Pl163 comes on
4. Check for a Temporary DTC with the scan tool.
ls Temporary DTC P 1163 indicated?
YES Replace the Ay'F sensor (Sensor 1).I
NO Intermittent failu re, system is OK at this time.
Check for poor connections or loose terminals at
the A'lF sensor (Sensor 1 ) and at the ECM. t
11-88
DTC Pl164: A,/F Sensor (Sensor 1) Circuit
Range/Performance Problem
1. Resetthe ECI\4 (see page 1t-4).
2. Start the engine. Holdtheengineat3,000 rpmwith
no load (in neutral) until the radiator fan comes on,
3. Test-drive in 3rd gear. Starting at 1,600 rpm,
accelerate using wide open throttle for at least
5 seconds. Then decelerate for at least 5 seconds
with the throttle completely closed until the A,/F
sensor readiness code is set to complete or
Temporary DTC P1 164 comes on.
4. Check for a Temporary DTC with the scan tool.
ls Temporary DTC P1164 indicated?
YES- Replace the A,,/F sensor (Sensor 1). I
NO Intermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the Ay'F sensor relay, at the Ay'F sensor (Sensor 1),
and at the EcM.l

Intake Air System
Throttle Body Test
NOTE:. Do not adjust the throttle stop screw. lt is preset at the
factory.. lf the malfunction indicator lamp (MlL) has been
reported on, check for diagnostic trouble codes(DLCS) (see page 11 3).
1. With the engine off, check the throttle cable
movement. The cable should move without binding
or sticking.
. lf lhe cable moves OK, goto step 2.. lf the cable binds or sticks, check it and its routing.. lf the cable isfaulty, reroute itor replace itand
adjust it (see page 11-163), then go to step 2.
2. l\4ove the throttle lever by hand to see if the throftle
valve and/or shaft are too loose or too tight.
. lf there is excessive play in the throttle valve
shaft, or any binding in the throttle valve at the
fully closed position, replace the throttle body.. lf thethrottlevalve and shaft are OK, goto step3.
3. Connect the scan toolto the DLC.
Turn the ignition switch ON (ll).
Check the throttle position with the scan tool. The
reading should be about 10% when the throttle is
fully closed and about 90% when the throttle is fully
openeo.
. lf the throttle position is correct, the throttle body
is OK.. lf thethrottle position is notcorrect, replace the
throttle body.
5.
11-160
!

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