coolant temperature HONDA CIVIC 2003 7.G User Guide

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'd)
PGM-FI System
The Programmed Fuel Injection (PGM-Fl) system is a
sequential multiport fuel injection system.
Air Conditioning {A/C) Compressor Glutch Relay
When the ECfM receives a demand for cooling from the
Ay'C system, it delays the compressor from being
energized, and enriches the mixture to assure smooth
transition to the AVC mode.
Air Fuel Ratio lA/Fl Sensor
The Ay'F Sensor operates over a wide airlfuel range. The
Ay'F Sensor is installed upstream of the TWC, and sends
signals to the ECM which varies the duration of fuel
injection accordingly.
SENSORTERMINALS
HEATERTERMINALS
Barometric Pressure {BAROI Sensor
The BARO sensor is inside the ECM. lt convens
atmospheric pressure into a voltage signal that the ECM
uses to modify the basic duration of the fuel injection
discharge.
ztRcoNtaELEMENT
HEATER
11-26
\,
Camshaft Position (CMPI Sensor B (Top Dead Center(TDCI Sensor)
The CMP sensor B (TDC sensor) detects the position of
the No. 1 cylinder as a reference for sequential fuel
injection to each cylinder.
Crankshaft Position (CKPI Sensor
The CKP sensor detects crankshaft soeed and
determines ignition timing and timing for fuel injection
of each cylinder as well as detecting engine misfire.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is a temperature dependent resistor(thermistor). The resistance of the thermistor decreases
as the engine coolant temperature increases.
MAGNET
TERMINAL

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'dl
ldle Control System Diagram
The idle speed of the engine is controlled by the ldle Air Control (lAC) varve:
'Aftertheenginestarts,theIACvalveopensforacertainamountoftime.Theamountofairisincreasedtoraisethe
idle sDeed.. When the engine coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. Theamount of bypassed air is controlled in relation to engine coolant temperature.
INTAKE MANIFOLDIAC VALVEAKE AIR DUCT
CLEANER
\
BLK/REO
YEL/BLK ---< FromPGM.FIMAINRELAY
THROTTLE AODY
Intake Air System Diagram
This system supplies air for engine needs. A resonator in the intake air
drawn into the svstem.
VARIOUSSENSOnS
pipe provides additional silencing as air is
THROTTLE AODYVARIOUSSENSORS
BLK
BLK
I
11-36
{

PGM-FI System
Component Location Index
CAMSHAFT POS]TION {CMP) SENSOR B(TOP DEAD CENTER (TDC}SENSORITroubleshootina. oaoe 1 1-95Replacement, p;ge 1-1.1 14
ELECTRICAL LOADDETECTOR {ELDITroubleshooting,page 1'l -92
INTAKE AIR TEMPERATURE{IATI SENSORTroubleshooting,page 'l'l-55
Replacement, page 11-'l 15
f- \
rl
KNOCK SENSORTroubleshooting, page 1 1-77Beplacement, page 11 115
ENGINE COOLANT TEMPERATURE(ECTI SENSORTroubleshooting, page 1 1-57Replacement, page 11 114
MANIFOLD ABSOLUTE PRESSURE(MAP) SENSORTroubleshooting, page 1 1-52
THROTTLE POSITIONITP} SENSORTroubleshooting, page 11-60CRANKSHAFT POSITIONICKPISENSORTroubleshooting, page'l 1-78Beplacement, page 1 1-'l 16
AIR FUEL RATIO {A/F)SENSOR ISENSOR 1}Trorrbleshooting, page 1 1-84Replacement, page 11- 1 13
{cont'd)
ii'- r'1
.I11 ---:,I''.!,i(..,.?:fir-J-
.....,..:--.
11-49

PGM-FI System
aDTG Troubleshootang (cont'dl
DTC P0128: Cooling System Malfunction
NOTE; lf the DTCS listed below are stored at the same
time as DTC P0128. troubleshoot those DTCS first, thenrecheck for P0128.
P0107, P0108, P1128, P1129: N4anifold absolutepressure (MAP) sensor
P] I06, P1 107, P1 108: Barometric pressure (BARO)
sensor
P1259: VTEC system
P01 16, P01 17, P01 18: Engine coolant temperature (ECT)
sensor
P01 12, P01 13: Intake air temperature (lAT) sensor
P0500: Vehicle speed sensor {VSS)P0335, P0336: Crankshaft position (CKP) sensor
P0300: Random misfire
P0301, P0302, P0303, P0304: No. 1, No. 2, No.3 or No.4
cylinder misfire
P0505: ldle control system malfunction
P1519: ldle air control (lAC)valve
DTC P0128 can occasionally set when the hood is
opened while the engine is running.
1. Check the engine coolant level
Is the engine coolant level low?
VES Refill the engine coolant. lf necessary, repair
the coolant leakage.l
NO Go to step 2.
2. Turn the ignition switch ON (ll), and make sure the
A,/C is off.
11-64
\
3. Check the radiator fan.
Does the tadiator fan keep running?
YES Checkthe rad iato r fan circuit (see page 10-
14), the radiator fan switch circuit (Short) (see page
10-'16), and the radiator fan switch (see page 10-17).
Also, inspect the ECT and IAT circuits and terminal
connections. lf the circuits, the switch, and the
connections are OK, update the ECI\4 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 thermostat (see page 10-8).1

ECM ldle Learn Procedure
The idle learn procedure must be done so the ECM can
learn the engine idle characteristics.
Do the idle learn procedure whenever you do any of
these actions:. Disconnect the battery.
Replace the ECM or disconnect its connector.
Reset the ECM.
NOTE: Erasing DTCS with the Honda PGM Tester
does not require you to do the idle learn procedure.
Remove the No.6 ECU {ECM) ( 15A) fuse from the
under-hood fuse/relay box.
Remove the No.19 baftery (80A) fuse from the under-
hood fuse/relay box.
Remove PGM-FI main relay 1.
Remove any of the wires from the under-hood fuse/
retay Dox.
Disconnect any of the connectors from the under
hood fuse/relay box.
Disconnect the connector between the engine
compartment wire harness and ECM wire harness.
Disconnect the G2 terminal from the transmission
ho u srng.
Disconnectthe G'l terminal from the body.
Disconnectthe G101 terminal from the cylinder head
cover.
Procedure:
To complete the idle learn procedure, do this:
1. Make sure all electrical items (Ay'C, audio, rear
defogger, l:ghts, etc.,) are off.
2. Start the engine, and hold it at 3,000 rpm with no
load {in neutral) until the radiator fan comes on, or
until the engine coolanttemperature reaches 194"F(90'c).
3. Let the engine idle for about 5 minutes with the
throttle fully closed.
NOTE: lf the radiator fan comes on, do not include its
running time in the 5 minutes.
11-139

Intake Air Bypass GontrolThermalValve Test
Special Tools Required
Vacuum Pump/Gauge,0 30 in. Hg A973X-041-XXXXX
1. Stan the engine. Then let it idl€.
NOTE: The engine coolant temperature must be
below 149'F (65'C).
2. Remove the vacuum hose (A)from the intake air
duct, and connect a vacuum pump/gauge to the
nose.
3. Raise and lowerthe engine speed. and make sure
the vacuum gauge reading changes as the engine
speeo cnanges.
lf the vacuum reading does not change, check for
these problems:
. Misrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines.. A cracked or damaged intake air bypass control
thermal valve.
4. Hold the engine at 3,000 rpm with no load (in
neutral) until the radiator fan comes on, then let it
id le.
5. Raise and lower the engine speed, and make sure
the vacuum gauge reading does not change as the
rpm cnanges.
lf the vacuum reading changes, check for these
proorems:
. l\4isrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines.. A cracked or damaged intake air bypass control
thermal valve.
11-161

EVAP System
DTC Troubleshooting (cont'dl
31. While monitoring FTP sensor voltage with theHonda PGM Tester, or measuring voltage betweenECM connector terminals E4 and E14, slowly pump
the vacuum oumD.
ECM CONNECTOR E 13lPI
Wire side ot female terminals
32. Continue to pump vacuum until the voltage drops
to about 1.5 V. Make sure the engine coolant
temperature is still above 95'F 135.C) and your
vacuum pump has no leak.
33. Monitor the voltage for 20 seconds.
Does the voltage drop 1.5V and hold for at least
20 seconds?
YES Inspect the EVAP canister vent shut valve
line and connections.l
NO-Go to step 34.
34. Turn the ignition switch OFF.
35. Discon nect the quick-con nect fitting (A) fromthe
EVAP canister, and plug the canister port {B).
36. Turn the ignition switch ON (ll).
11-184
42. Turn the ignition switch ON (ll).
I
38.
39.
37. While monitoring FTP sensor voltage with theHonda PGM Tester, or measuring voltage betweenECM connector terminals E4 and E 14, slowly pump
the vacuum pump.
ECM CONNECTOR E {31PI
Wire side of lemale terminals
Continue to pump vacuum until the voltage drops
to about 1.5V. Make sure the engine coolant
temperature is still above 95"F (35"C) and your
vacuum pump has no leak.
Monitor the voltage for 20 seconds
Does the voltage hold for at least 20 seconds?
YES Inspecl the fuel tank vapor control lineand
connections.I
NO Go to step 40.
Turn the ignition switch OFF.
Disconnect the purge line hose {A) from the
canister at the metal line and plug the hose (B).
40.
41.

43. While monitoring FTP sensor voltage with the
Honda PGM Tester, or measuring voltage between
ECM connector terminals E4 and E14, slowly pump
the vacuum pump.
ECM CONNECTOR E {31P)
Wire side of female terminals
Continue to pump vacuum until the voltage drops
to about 1.5V. Make sure the engine coolant
temperature is still above 95'F (35'C) and your
vacuum pump has no leak.
Monitor the voltage continuously for 20 seconds.
Does the voltage drop to 1.5 V and hold f or at
least 20 seconds?
YES Inspect the EVAP canister purge valve line
and connections. lf they are OK, perform the EVAP
two way valve test (see page 11-186) and the fuel
tank vapor control valve test (see page 1'l-187) l
NO-Replace the EVAP canister
(see page 11-189).1
44.
45.
11-185