Page 345 of 1681
'il
Emission Gontrol System
Positive Crankcase Ventilation (PCV) System
Description
The Positive Crankcase Ventilation (PCV) system is
designed to prevent blow-by gas from escaping to the
atmosphere. The PCV valve contains a spring-loaded
plunger. When the engine starts. the plunger in the PCV
valve is lifted in orooonion to intake manifold vacuum and
the blow-by gas is drawn directly into the intake manifold.
PCV VALVE
MANIFOLD
+: BLOW-BY VAPOR{-: FRESH AIR
11-140
Inspection
1. Check the PCV hoses and connections for leaks and
croggrng.
BREATHERHOSE
l.--:\
,.r
I
2.At idie, make sure there is a clicking sound from the
PCV valve when the hose between PCV valve and
intake manilold in lightly pinched with your fingers
or plters.
lf there is no clicking sound, check the PCV valve
grommet for cracks and damage. lf the grommet is
OK, reolace the PCV valve and recheck.
Gently pinch here.
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$ure sensor
The scan tool indicates Diagnostic Trouble Code (DTC) P0453: A high voltage problem in the Fuel Tank Pressure
sensor.
ECM OONNECTOR D IT6PI
PTANKILT GRNI
Wire side of female terminals
FUEL TANKPRESSURE SENSOR3P CONNECTOR {C7921
\
voc2
{YEL/BLU}
sG2IGBN/BI.KI
Wire side of female terminals
The Mll- hes bson.opofiad on.DTC m453 b stored.
Check ihe vacuum lino3:Check the vacuum Iines ot the{uel tank pressure sensor for mis-routing, leakage, breakage andcroggrng.
Are the vacu!m lin€s OK?
Problem vsrification:1. Do the ECM Reset Procedure.2. Remove the fuel fill cap.3. Turn the ignition switch ON {ll).4. Monitor the FTP sensor volt-age with the Honda PGMTester, or measure voltagebetween body ground andECM connector terminal D15.Intormittont failu.e. syst6m is OK
at ihi3 time, Chack for poor con.nections or loo3e wires at C421{locatod abovo undel-dash fu3e/rolay box), C510 (loc.ted undoracc6s3 Dan6ll, C792 Ituol trnkDro.su.6 sen3or l and ECM,
ls there approx. 2.5 V?
Check tor an open in the wire(SG2 lino):1. Turn the ignition switch OFF.2. Reinstall the fuel fill cap.3. Disconnect the fuel tank pres-
sure sensor 3P connector.4. Turn the ignition switch ON {ll}.5. Measure voltage between thetuel tank pressure sensor 3Pconnector terminals No. 1 andNo.2.
Rcpair opon in the wire b6tw66nthe fu6l tank prasSuaa 36n3or endECM {Dr1).ls there approx. 5 V?
Check lor a short in tho wirc{PTANK linel:Measure voltage between thefueltank pressure sensor 3P con-nector terminals No. 2 and No. 3.
YES
sG2IGRN/BLKI
PTANKILT GRNI
{To page 1l-145)
11-144
Page 350 of 1681
(From page 11 144)
ls there approx. 5 V?
Check foi an opon in th. wi.e{PTANK line}:Measure voltage between ECMconnector terminals D15 and D11.
Ropair opon in the wire betwe€nihe lual tank ore$ure sen3or andthe ECM {D151,
ls there approx.5 V?
Substitute e known-good ECMand racheck. lf normal fuel tankpressure sensor is indicated,replace the original ECM.
ECM OONNECTOR D I16P)
PTANK(LT GRNISG2 IGRN/BLKI
Wire side of female terminals
11-145
Page 351 of 1681

Il
1l
Iil
Emission Control SYstem
EVAPrHREEWAYVALVE
tFi4s6l
fPf 45? I
Evaporative Emission {EVAP) Controls (cont'd)
Possible Csuse
. Fuel fill cap
. Vacuum Connections
. FuelTank
. EVAP Control Canister Vent Shut Valve
. EVAP Control Canister Vent Shut Valve Circuit
. EVAP Purge control Solenoid Valve
. EVAP Purge Control Solenoid Valve Circuit
. EVAP Bypass Solenoid Valve
. EVAP Bypass Solenoid Valve Circuit
o FuelTank Pressure Sensor
. Fuel Tank Pressure Sensor Circuit
. EVAP Control Canister
. Throftle Body
Troubloshooling Flowchart
The scan tool indicates Diagnostic Trouble Code {DTC) P1456: Evaporative Emission (EVAP) control system leak
detected (fuel tank system).
ThescantoolindicatesDiagnosticTroubleCode(DTC)P't457:EvaporativeEmission(EVAP)controlsystemleak
detected (EVAP control canister system)'
VACUUMPUMP/GAUGE,0 - 30 in.Bs
A973X - 041 -
xxxxx
EVAP
CANISTER
EVAPCONTROLCANISTERVENTSHUTVALVE
O-RINGReplace.
ECM CONNECTOR A I32P)
(To page 11-147)
- Tho MIL ha3 bcan t6po.tod
on.- DTC P1,t56 or P1457 i! 3toLd.
Chcck the EVAP contiol canittc.
vont shut valva:1. Disconnect the vacuum hose
Irom the EVAP three way
valve and conned a vacuumpump to the hose
2. Remove the EVAP control
canister vent shut valve {rom
the canister.3. Turn the ignition switch ON lll)
4. Apply vacuum to the hose
Chack tor a lhort in tho wire
lVSv linol:Disconnect the 2P conn€ctor from
the EVAP control canister vent
Does the valve hold vacuum?
Rcp.i. ahoft in thc wir. bctw.cn
th6 EVAP conlrol caniator v.nt
3hut valve snd the ECM lA29).Does the valve hold vacuum?
Check tha EVAP coitlol canittcr
vent 3hut valvo:1. Turn the ignition switch OFF
2. Connect ECM connoctor ter'
minal A29 to bodY ground
whh a iumPer wlre
3. Turn the ignition switch ON (ll).
4. Apply vacuum to the hose.
Baplaca tha EVAP control c!ni!'
td vant 3hul Yalvc.
Does the valve hold vacuum?
38t0tl
1215[6'tat92Au232a
2t27a22
VSV {LT GRN) I JUMPER WIRE
Wire side o{ {emale terminals
11-146
{To page 11'147)
Page 352 of 1681

(From psge 11-146)
(To page 11-148)
Chack tho vldlum wh.n cold:'1. Disconnscl the vacuum hoseshown from the EVAP controlcanrster ano connect a vacuumgauge to the hose.2. Start the engine and aliow itto idls.NOTE: Engine coolant tem-porat{rre must be below 154"F{68'C} or A/C switch OFF.3. Ouickly raise the engine speedto 3,000 rpm.
lFrom page 11-146)
Check lor an opon in lhe wir€(lG1 lin6l:1. Turn the ignition switch OFF.2. Disconnect the 2P connectorlrom the EVAP control canis-ter vent shut valve.3. Turn the ignition switch ON (ll).
4. Measure voltage between theEVAP control canister vent shutvalve 2P connector terminalNo. 2 and body ground.
Ropair open in the wir6 betweonthe EVAP control canistor v6ntshut valve end the No. 15 ALTER-NATOR SP SENSOR 17.5 Al tu!e.
Ch€ck tor rn op€n in iho wire IVSVline):1. Turn tho ignition switch OFF.2. Reconnect the 2P connectorto the EVAP control canistervent shut valve,3. Turn the ignition switch ON (ll).
4, Measure vo ltage betweenECN/l connector terminals A29and A10.
Repair open in the wire beiwa€nthe EVAP cont.ol cenister ventshut valve and the EcM {4291.ls there baftery vohage?
ReDlacs tho EVAP cont.ol canis"ter vent shut valve.
EVAP CONTROLCANISTER VENT SHUIVALVE 2P CONNECTOR IC224)
.FJ.\1121-T rcl
(D (BLK/YEL)
I
Wire side ot female terminals
ECM CONNECIOR A {32P}
VSV ILT GRNI
Wire side of femaletermtnars
VACUUMPUMP/GAUGE,0 - 30 in.H94973X -
0a1 - xxxxx
(cont'd )
11-147
PG1 (BLKI
rl
4lq-r'rri l12t5t6t?l8r@llzzlzslul
25212a2
__l