Page 303 of 1681

ldle Control System
ldle Control System
i P0505 | fne scan tool indicates Diagnostic Trouble Code (DTC) P0505: ldle control system malfunction,
NOTE: ll DTC Pl508 is stored at the same time as DTC P0505, troubleshoor DTC P1508 first. then troubleshoot DTC P0505.
Possible Cause
. IAC valve mechanical malfunctiorr
. Fast idle thermo valve malfunction (A"/T)
. Throttle body clogged port, improper adjustment
. Intake manifold, gasket leakage
. Intake air hose loose, leakage
a Vacuum hoses leakage
. ECT sensor incorrect output
. Throttle Position sensor incorrect output
Troubleshooting Flowchart
Problem verification:1. Start the engine. Hold theengine at 3,000 rpm wath noload 1in Park or neutral) untilthe radiator fan comes on,then let it idle.2. With the scan tool, check thefollowing items.- Throttle position should beapprox. 10% with the throttle fully closed.Engine coolant tempera-ture should be 116 212F(80 - 100'c).lf they are not within thespec., repair the faulty sensor crrcuft,3 Check the engine speed atidle with no-load conditions:headlights, blower fan, reardefogger, radiator fan, and airconditioner are not operating,
- The MIL has been reported on.- DTC P0505 is stored.
ls it 750 t 50 rpm (81881,
818C1 engines), 800 I 50 rpm(818C5 engine)?
Intermittent failur6, svstsm is OKat this tim€.
ls it 550 rpm (81881,818C1
engines), 600 rpm {818C5enginelor less?
-98
(To page 11'99)(To page 11-99)
Page 333 of 1681
r
Intake Air System
System DescriptioSystem uescnpllon
The system supplies air for all engine needs. lt consists of the intake air pipe. Air Cleaner (ACL), intake air duct, Throttle
Body (TB), ldle Air Control (lAC) Valve, fast idle thermo valve (A,/T model only), and intake manifold.
A resonator in the intake air pipe provides additional silencing as air is drawn into the system.
B18Cl engine lB18Bl, B18C5 enginos does not havs the IAB systeml:
IABCONTROLsollNolDVALVE
VARIOUSSENSORS
IABCONTROLDIAPHRAGM
IiITAKEAIR PIPE
INTAKE MANIFOLDINTA|(EAIRDUCT
RESONATOR
Page 338 of 1681
Disassembly
NOTE:
. The throttle stoD screw is non-adiustable.
. After reassembly, adjust the th rottle ca ble (page 11-130, 131),andA/Tthrottlecontrol cable (section l4)Ior cars with A/T.. The TP sensor is not removable.
IOLE ADJUSTINGSCREW
FAST IDLETHERMOVALVE {A/T model onlylInspectaon, page 1 1-l 10
-l
12.2 kgf.m, 16 lbf.ft)
1 1-133
Page 343 of 1681

t"iI
Emission Gontrol System
System Description
Three Way Catalytic Converter (TWCI
\
t
The emission control system includes a Three Way
Catalytic Converter (TWC), Positive Crankcase Ventilation
(PCV) system and Evaporative Emission (EVAP) Control
system. The emission control system is designed to meet
tederal and state emission standards.
InsDeciion
!@@ Do not smoke during this procedure. Keep
any open llame away from your work area.
1. Start the engine. Hold the engine at 3,000 rpm with
no load {in Park or neutral) until the radiator fan
comes on, then let it idle.
2. Connect a tachometer.
Check and adjust the idle speed, if necessary (see
page '11-11 ! ).
Warm up and calibrate the CO meter according to the
meter manufacturer's instructions.
Check idle CO with rhe headlights, heater blower,
rear window defogger, cooling fan, and air condition-
er off.
NOTE: {Canada) Pull the parking brake lever up.
Start the engine, then check that the headlights are
olf.
CO meter should indicste 0.17o maximum.
DescriDtion
The Three Way Catalytic Converter {TWC) is used to convert hydrocarbons (HC), carbon monoxide (CO), and oxides of
nitrogen (NOx) in the exhaust gas, to carbon dioxide (COr), dinitrogen {Nr) and water vapor.
Bl8Cl engine l818Bl, 818C5 engines is similar):
FRONT OFVEHICLE
PRIMAEYHEATEDOXYGEN SENSORIPRIMARY HO2S}
HOUSING
WAYCATALYSTS
SECONOARYHEATEDOXYGEN SENSOR{SECONDARYH02St
\
Page 346 of 1681

Evaporative Emission (EVAP) Controls
,J
a
DescriDtion
The evaporative emission controls are designed to minimize the amount of luel vapor escaping to the atmosphere. Thesystem consists of the following components:
A. EvaporativeEmission lEVAPlControlCanister
An EVAP control canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from theEVAP control canister into the engine and burned.
B. Vapol Purge Control System
EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a pon
on the intake manifold. The purging vacuum is controlled by the EVAP purge control solenoid valve.
C. Fuel Tank Vapor Control System
When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the varve opens anoregulates the flow of fuel vapor to the EVAP control canister.
FrcmNo. 15FUELTANKPRESSURESENSOR
EVAPTHREE WAYVALVE
EVAP CONTROLCANISTENVENT SHUT VALVE
YEL/- BLK
EVAPBYPASSSOLENOIDVALVE
LT GRN
RED/EVAPTWO WAYVALVE
FUEL TANKEVAP VALVE
FUEL TANK
EVAP PURGE CONTROL SOLENOID VALVE DUTY CON-
TROLLED AFTER STARTING ENGINE
?!l ---- 311'AiS-*(7.s Al
FromPGM.FIMAIN RELAY
VARIOUSSENSORS
----<
YEL
EVAP PURGECONTROLSOLENOID VALVE
(cont'd)
-141
Page 347 of 1681

lT
Emission Control System
YES
{To page 11-143}
Fu€l Tank Pressure Sensor
The scan tool indicates Diagnostic Trouble Code (DTC) P0452: A low voltage problem in the Fuel Tank Pressure
sensor.
The fuel tank pressure sensor converts tuel tank absolute pressure into electrical signals and inputs the ECM.
Evaporative Emission (EVAP) Controls (cont'dl
OUTPUTVOLTAGE(vl
4.5
0.5-7 kPel-50 mmHg,-2 in.Hgl
+7 lPe
l5o mmHg,2 in.Hgl
PRESSURE
\*
Eclrl CONNECToR o {lEPl
PTANK(wltT/BLul
vcc2IYEL/BLU}
Wire side of lemale terminals
FUEL TANKPRESSURE SENSOR
3P CONNECTOR (C792)
The MIL ha3 beon roportod on.OTC F0452 i3 storad.
Chock the vscuum lines:Check the vacuum lines otthe fueltank pressure sensor for misrout-ing, leakage, breakage and clog-ging.
Are the vacuum lines OK?
Problgm verilication:1. Do the ECM Reset Procedure.2. Remove the fuel fill cap.3. Turn the ignition switch ON lll).4. Monitor the FTP sensor volt-age with the Honda PGMTester, or measure voltagebotween body ground and' ECM connector terminal D15.Int6rmittent tailure, 3ystem i3 OKat thb tirn6. Chock lor poor con-n.clions or loo3e wire3 ot C421{locltod rbovo under-d!.h fuso/r.lay boxl, C510 lloc.ted undo.rcc.rs panoll, C?92 Ituel trnko.6sura i€nior I lnd ECM.
ls there approx.2.5 V?
Check to. an opon in wi.a {VCC2line):1. Turn the ignition switch OFF.2. Reinstall the fuel fill cap.3. Disconnect the luel tank pres'su re sensor 3P connector.4. Turnthe ignition switch ON (ll).
5. Measure voltage between thetuel tank pressure sensor 3Pconnector terminals No, 1 andNo.2.
R.pai. opcn in thg wir6 bdtwoonthc fual tank pro$ure 3enlor andtho EcM lDlo).ls there approx. 5 V?
11-142
Wire side oI temale terminals
Page 348 of 1681
{From page 11-142i
Chock lor a short in tho wi.oIPTANK linel:Measure voltage between the fueltank pressure sensor 3P connec-tor terminals No. 2 and No. 3.
ls there approx. 5 V?
Chock for.3hort in th6 wi.e(PTANK lincl:1. Turn the ignition switch OFF.2. Disconnect the ECM connec,tor D (16P).
3. Check lor continuity betweenthe {uel tank pr€sslrre sensor3P connector terfiinal No. 3and body ground.
Ropri. 3hon in tho wira betwaGnthe fuel t.nk prosaura san3or andECM tD15t.
Substituta s known-good ECM.nd recheck. It normel fuel tenkpressure son30r is indicatod,raplacg tho o.iginal ECM.
FUEL TANKPRESSURC SENSOR3P CONNECTOR lc792l
PTANKILT GRN}
sG2IGRN/BLKI
Wire sido of temale terminals
(cont'd)
11-143
Page 349 of 1681

rI
Emission Control System
Evaporative Emission (EVAPI Controls (cont'd)
Fuel Tank Pre$ure sensor
The scan tool indicates Diagnostic Trouble Code (DTC) P0453: A high voltage problem in the Fuel Tank Pressure
sensor.
ECM OONNECTOR D IT6PI
PTANKILT GRNI
Wire side of female terminals
FUEL TANKPRESSURE SENSOR3P CONNECTOR {C7921
\
voc2
{YEL/BLU}
sG2IGBN/BI.KI
Wire side of female terminals
The Mll- hes bson.opofiad on.DTC m453 b stored.
Check ihe vacuum lino3:Check the vacuum Iines ot the{uel tank pressure sensor for mis-routing, leakage, breakage andcroggrng.
Are the vacu!m lin€s OK?
Problem vsrification:1. Do the ECM Reset Procedure.2. Remove the fuel fill cap.3. Turn the ignition switch ON {ll).4. Monitor the FTP sensor volt-age with the Honda PGMTester, or measure voltagebetween body ground andECM connector terminal D15.Intormittont failu.e. syst6m is OK
at ihi3 time, Chack for poor con.nections or loo3e wires at C421{locatod abovo undel-dash fu3e/rolay box), C510 (loc.ted undoracc6s3 Dan6ll, C792 Ituol trnkDro.su.6 sen3or l and ECM,
ls there approx. 2.5 V?
Check tor an open in the wire(SG2 lino):1. Turn the ignition switch OFF.2. Reinstall the fuel fill cap.3. Disconnect the fuel tank pres-
sure sensor 3P connector.4. Turn the ignition switch ON {ll}.5. Measure voltage between thetuel tank pressure sensor 3Pconnector terminals No. 1 andNo.2.
Rcpair opon in the wire b6tw66nthe fu6l tank prasSuaa 36n3or endECM {Dr1).ls there approx. 5 V?
Check lor a short in tho wirc{PTANK linel:Measure voltage between thefueltank pressure sensor 3P con-nector terminals No. 2 and No. 3.
YES
sG2IGRN/BLKI
PTANKILT GRNI
{To page 1l-145)
11-144