2002 HONDA CIVIC Fuel

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
{

Evaporative Emission (EVAPI Control Diagram
The EVAP controls minimize the amount of fuel vapor escaping to the atmosphere. Vapor from the fuel tanK rstemporarily stored in the EVAP canister until it can be purged from the canister into the engine and burneo.
. The EVAP canister is purged by drawing fresh air through it and into a port on the intake manifold.The purging vacuum is controlled by the EVAP canister purge valve, which operates whenever engine cootanttemperature is above 149'F (65"C).
'WhenvaporpressureinthefueltankishigherthanthesetvalueoftheEVAPtwowayvalve,thevalveopensano
regulates the flow of fuel vapor to the EVAP canister.'Duringrefueling,thefueltankvaporcontrol valve opens with the pressure in the fuel tank, and feeds the fuel vaDorto the EVAP canister.
FUEL TANKVAPORRECIRCULATIONVALVE
FUEL TANKVAPORSIGNAL TUBE
BLU/RED
FUEL FILL CAP
BLK
+EVAPCANISTER
FUEL TANKVENT SHUTVALVE
BLK/YELFrom-- FUEL TANKVAPORRECIRCULATIONTUBE
EVAPCANISTER
EVAP TWO WAYVALVE
(cont'd)
11-37

Fuel and Emissions Systems
I
a
a
System Descriptions (cont'd)
ECM Circuit Diagram
CONNECTOi
mrrrrn
CMP SENSOR B(TDC SENSOn)
I-BRN/YEr-
11-38
\,

Fuel and Emissions Systems
System Descriptions (cont'dl
ECM Circuit Diagram {cont'd)
\
-{ffi]---1t-|
IATSENSOR
-{El------l
ECTSENSOS
T_""",,..
I-BFN/YEL
ft^--l
,","., J t-|':I REVERSEI LocKI soleloto+ vaLvE
t!j]]
CMPSENSOAA
L-IJUNCTIONI CONNECTOR
-
11-40

Fuel and Emissions Systems
a
a
a
System Descriptions (cont'd)
ECM Circuit Diagram lcont'dl
IGP2
YEI/BLK
VET/BLK
---rF-rl-lF-forl--JliD\l
--t-l
MAIN BETAV 2
t_,",
f-"'*'o""
tr
:tl-,r'l r,
-,u-
I SENSOS
11-42
IMMOAIL|zER UNIT

Fuel and Emissions Systems
a
System Descriptions (cont'dl
ECM Circuit Diagram (cont'd)
L
!UNDER.HOODFUSE/RELAY9OX
lalLREllY _ _l
CONN€CTOF
CONNECTOi
WHI/NED
BLK/YET
11-44

""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.