2003 HONDA CIVIC Ignition switch

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
(
{
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

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

PGM-FI System
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DTC Troubleshooting
DTC P0107: MAP Sensor Circuit Low Voltage
1. Turn the ignition switch ON (lli.
2. Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg,30 in.Hg)or 2.9 V
indicated?
YES Intermittent failu re, system is OK at this time.
Check for poor connections or loose terminals at
the MAP sensor and at the ECM.I
NO-Go to step 3.
3. Turn the ignition switch OFF.
4. Disconnect the MAP sensor 3P connector.
5. Turn the ignition switch ON (lll.
6. lvleasure voltage between MAP sensor 3P
conneclor terminals No. 1 and No. 3.
1.
sGl{GRN/WHTI
Wire s de of femaleterminais
ls there about 5 V?
YES Go to step 8.
NO-Go to step 7.
Measure voltage between EClvl connector
terminals 41 1 and 42'1.
ECM CONNECTOR A 13'IP}
MAP SENSOR 3P CONNECTOF
vccr{YEL/BED)
sGr{GRN/WHT}
11-52
Wire side of female terminals
\
8.
ls there about 5 V?
YES-Repair open in the wire between the Eclvl(A21)and the MAP sensor.l
NO Update the ECM if it does not have the latest
software, or substitule a known-good ECM, then
recheck (see page 'l 1-6). lf the symptom/indication
goes away with a known-good ECfvl, replace the
original ECM.I
Check the MAP with the scan tool.
ls 2 kPa (15 mmHg,0.6 in.Hg) ot less or 0 V
ind icated?
YES-Go to step 9.
NO Replace the lvlAP sensor.l
Turn the ignition switch OFF.
Disconnect ECM connector A (31P).
Check for continuity between MAP sensor
connector terminal No. 2 and body ground.
MAP SENSON 3P CONNECTOA
ls therc continuity?
YES-Repair short in the wire between the ECM(A19) and the MAP sensor.l
NO 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.I
9.
'10.
11.
\

DTC P0108: MAP Sensor Circuit High Voltage
'1. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle.
2. Check the MAP with the scan tool.
le about 101 kPa (780 nmHg, 30 in.Hg) ot highet,
or about 2.9 V or higher indicated?
YES Go to step 3.
NO-lntermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the MAP sensor and at the ECM.I
3. Turn the ignition switch OFF.
4. Disconnectthe MAP sensor 3P connector.
5, Connect MAP sensor 3P connector terminals No. 2
and No. 3 with a jumper wire.
MAP S€NSOR 3P CONNECTOR
MAP{GRN/REO}SG1 (GRN/WHTI
JUMPER WIRE
Wire side of female terminals
6. Turn the ignition switch ON (ll).
7. Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg,30 in.Hg) ot higher,
or about 2.9 V or higher indicated?
YES-Go to step 8.
NO Replace the MAP sensor.I
8. Remove the jumper wire.
123
9. Measure voltage between MAP sensor 3P
connector terminals No. 1 and No. 3.
MAP SENSOR 3PCONNECTOF
vccl{YEL/RED) l,lo cll.l.rl
I lsct
d) l{GRN/wHrr
YIilll
Wire side of female lerminals
ls there about 5 V?
YES Go to step 10.
NO Repair open in the wire between the ECM
(A1 1 ) and the MAP sensor.I
Turn the ignition switch OFF.
Connect ECM connector terminals A11 and A19
with a jumper wire.
ECM CONNECTOR A {31PI
Wire side of fema e te.minals
Turn the ignition switch ON (ll).
Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg, 30 in.Hg) or higher,
or about 2.9 V ot higher indicated?
YES Update the ECM if it does not have the lalest
software, or substitute a known-good ECM, lhen
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known good ECM, replace the
original ECM.I
NO-Repair open in the wire betlveen the ECI\il
(A19) and the MAP sensor.I
10.
11.
JUMPER WIAE
11-53

PGM-FI System
a
DTC Troubleshooting (cont'dl
DTC Pl128: MAP Sensor Signal Lower Than
Expected
1. Turn the ignition switch ON (ll).
2. Check the MAP with the scan tool.
ls 54.1 kPa(406mmHg, 16.0in.Hg), 1.6 V, or
higher indicated?
YES- Intermittent failure. system is OK at this
time.I
NO Replace the MAP sensor.l
11-54
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DTC Pl129: MAP Sensor Signal Higher Than
Expected
1. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then Iet it idle.
2. Check the MAP with the scan toot.
ls 36.9 kPa (277 mmHg, 10.9 in.Hg), 1.1 V , or less
indicated?
YES- lntermittent failure, system is OK at this
time.l
NO Replace the MAP sensor.l
\