Page 416 of 1395

Emission Control System
Fuel tank pros3ure sensor tost.(The continuetion of DTC Pl456t.oubls3hooting.,
Chock the tusl trnk pr€3sure sen-sor:1. Remove the fuel fill csp.2. Turn the ignition switch ON fll).3. Monitor the FTP Sensor voh-age with th€ Honda PGMTester, or measure voltagebetween ECM/PCM conn€ctorterminals A29 and C18.
Choct ths vacuum linsr forra3triction o. blockago ropair a!nect*rary. It OK, replaca the fu6ltank praituJc sentot.
ls there approx. 2.5 V?
Check the fuel t nk pressuae 3en-sor:1. Turn the ignition switch OFF.2. Disconnect the hose betweenthe EVAP two way valve andthe tueltank pressure sensor atthe EVAP two way valve end.3. Connect a vacuum pump tothe open end ofthat hose.4. Turn the ignition switch ON 0l).5. Monitor the FTP Sensor volt-age with the Honda PGMTestet, or measure voltagebetween ECM/PCM connectorterminals 429 and C18, andcarefully apply vacuum on thehose one stroke at a lime.6. The voltage should smoothtydrop from the staning approx.2.5 V down to approx. 1.5 V.Stop applying vacuum whenthe voltage drops to approx.1.5 V or damage to the fueltank pressure sensor fiayoccur,
Fu.l tank pressu.c a€nlor b OK.Oo thc EVAP pulge controlsolenoid valve toat (3€€ prgo 11-2151.
Does the voltage drop to approx.1.5 V and hold?
Evaporative Emission (EVAPI Controls (contd)
lP14s6l("ont,a)
ECM/PCM CONNECTORS
SG2 IGRN/BLKI
Wire side oI female terminals
FUEI- TANKPRESSURESENSOR
VACUUMPUMP/GAUGE,0 - 30 in.HgA973X - ill -
xxxxx
EVAP TWOWAY VALVE
11-214
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Page 420 of 1395
Emission Control System
Evaporative Emission IEVAPI Controls (cont'd)
lTi,t56l ("onto)
Vacuum hoses and connectionstelit.(The continuarion of DTC P1456troubleshooiing.l
Check the vacuum ho3es andconnect|ons:Check the following parts forleaks at atmospheric p ressu re{see page 11-204).. Fueltank. Fuel fill cap. Fuelfill pipe. EVAP two way valve. Fueltank pressure sensor
Repair or replaco the parts.
Substitute a known-good ECM/PCM and recheck. lf symptom/indication goes away, replac€the original ECM/PCM.
11-218
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Page 423 of 1395

EVAP bypass solenoid valv€ test.
{The continuation of DTC P1457
troubleshooting.l
Check the EVAP bypass 3olenoid
1. Disconnect the vacuLlm hose
from the EVAP two way valve,
and conned a vacuum PUmPto the hose.2. Turn the ignition switch ON (ll).
3. Apply vacuum to the hose
EVAP bvpas3 30lsnoid vrlvo/
EVAP two way v.lve is OK. Do
the EVAP control canisler vent
3hut v.lve te3l (see Psge11'2221.
Does the valve hold vacuum?
Ch6ck the EVAP byp.ss solenoid
'1. Turn the ignition switch OFF
2. Disconnect the EVAP bypass
solenoid valve 2P connector.
3. Check {or continuity between
the EVAP bypass soleno id
valve 2P connector termlnal
No. 2 and body ground
ReDlace the EVAP bypass 3olenoid
valve and O-rings.
Check for a short in lhe wire
{2WBS linel:1. Disconnect ECM/PCM connec
tor A (32P).
2. Check lor continuity betlveenthe EVAP bypass soleno id
valve 2P connector termrnalNo. 2 and body ground.
Rcpsir short in th. wire bgtwoen
the EcM/PCtrl lA3l lnd the EVAP
bypa$ solenoid valvo.ls there continuitY?
Sub3tiiute . known'good ECM/
PCM End recheck. lI sYmptom/
indication goe3 away, tePlace
the original ECM/PCM.
EVAPBYPASSFUELTANKPRESSUBE SENSORSOLENOIDVALVEEVAP TWO WAY
VALVE
VACUUMPUMP/GAUGE,0-30 in.HgA973X -
041 -
xxxxx
EVAP AYPASS SOLENOID
VALVE 2P CONNECTOR (C647}
q
@)
T
t.'-+lt1t?l
| 2wBs
(d1 terul
Y-L
Wire side offemaleterminals
2WBS(BLU}
(cont'd)
11-221
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Page 425 of 1395

Canbter system leak test
{The continuation of DTC P1457
trouble3hootin9.)
Chock the EVAP control canistervent shut valve line and connoc'
tonS:1. Turn the ignition switch OFF
2. Connect to three'way tee fit_
tings into the hose from the
EVAP control canister to the
EVAP two way valve. Connect
the fuel tank pressure sensor
to one of the tee fittings and
the vacuum PumP to the other'
3. Remove the vent hose from
the EVAP control canister vent
shut valve and cap the Pon to
seal the fresh air vent Ior the
EVAP control canister.4. Turn the ignition switch ON (ll).
5. While monitoring the FTP
Sensor voltage with the Honda
PGM Tester, or measurangvoltage between ECM/PCM
connector terminals A29 and
C18 slowly PumP the vacuumpump using a stroke every 1 -
2 seconds.6. Continue to PumP vacuum
until that voltage droPs to
approx. 1.5 V.NOTE: Make sure that the
engine coolant temPeraturestillabove 95'F (35'Cland Yourvacuum PumP has no leak
7. Monitor that voltage for 20
seconds.
Check the EVAP Pu.ge control
solenoid valve line and connec-
tions:1. Turn the ignition switch OFF.
2. Disconnect the Purge lane
hose from the EVAP control
canister and Plug the Port3. Turn the ignition switch ON (lli.
4. While monitoring the FTP
Sensor voltage with the Honda
PGM Tester, or measuringvoltage between ECM/PCM
connector terminals A29 and
Cl8 slowly PumP the vacuumpump using a stroke every 1 -
2 seconds.5. Continue to pump vacuum
until that voltage droPs to
approx. 1-5 V.NOTE: Make sure that the
engine coolant temPeraturestill above 95'F (35"C) and Yourvacuum pump has no leak-
6. Monitor that voltage tor 20
seconds.
Doesthe voltage drop to 1.5 V
and holds at least 20 seconds?
lGp€ct the EVAP control cani3tel
vent 3hut valvo line and connec_
tion5.
Inlpect tho EVAP Putge control
solenoid valvo line and connec'
tion3. It th6y lro OK, do the EVAP
two way valve te3t (seo page 11-
2211.
Does the voltage drop to 1.5 V
and holds at least 20 seconds?
Reolace the EVAP conirol canister.
EVAPBYPASSSOLENOIDVALVE
FUEL TANK
EVAPCONTROL
VENTSHUTVALVE
EVAPCONTROLCANISTER
SENSOR
EVAP TWO WAYVALVE
EVAPTHREE
VALVE
ttrrL
ta
VACUUMPUMP/GAUGE,0 - 30 in.HgA973X -
041 -
XXXXX
FITTINGS
ECM/PCM CONNECTORS
A {32P)
PTANK ILT GRN)
c (31Pt
SG2 {GRN/BLK)
Wire side of female terminals
{cont'd)
11-223
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Page 426 of 1395

Emission Control System
Evaporative Emission (EVAP) Controls (cont,dl
Evaporative Emission (EVAP) Two Way Valve Testing
'97 model:
1. Remove the fuelfill cap.
2. Remove the vapor Iine from the EVAP two wayvalve on the fuel tank, and connect it to a T_fittingfrom a vacuum gauge and a vacuum pump asshown.
VACUUM,/PRESSURE GAUGEotJAz - 001 rDoBT-FITTINGVACUUMPUMP/GAUGE,0 - 30 in.HgA973X-041-XXXXX
3. Apply vacuum slowly and continuouslv whilewatching the gauge. The vacuum should stabilizemomentarily at 0.7 - 2.0 kpa (5 - 1S mmHg, 0.2 _ 0.6in.Hg).
lf the vacuum stabilizes (valve opens) below0.7 kPa (5 mmHg,0.2 in,Hg) or above 2.0 kpa(15 mmHg, 0.6 in.Hg), install a new valve and retest.
4.Move the vacuum pump hose from the vacuum fit_ting to the pressure fitting, and move the vacuumgauge hose from the vacuum side to the pressureside as shown.
PiESSURESIDE
5. Slowly pressurize the vapor line while watching thegauge. The pressure should stabilize at 1.3 - 4.7 kpa(0 - 35 mmHg, 0.4 - 1.4 in.Hg).. lf the pressure momentarily stabilizes (valve
opens) at 1.3 - 4.7 kpa (10 - 35 mmHg, 0.4 _ 1.4in. Hg), the valve is OK.. lf th6 pressure stabilizes below 1.3 kpa fio mmHg,0.4 inrHg) or above 4.7 kpa (35 mmHg, 1.4 in.Hg),install a new valve and retest.
T-FITTING
11-224
.98 - 0O models:
1. Remove the fuel fill cap.2. Remove the vapor line from the EVAP two wayvalve {located above the EVAP control canister). andconnect it to a T-fitting from vacuum gauge andvacuum pump as shown.
VACUUM/PRESSUFE
VACUUM PUMP/GAUGE,0 - 30 in.HgA973X - 041 -
xxxxx
5.
Apply vacuum slowly and continuously whilewatching the gauge.
The vacuum should stabilize momentarily at O.g _
2.1 kPa (6 - 16 mmHg, 0.2 - 0.6 in.Hg).lf the vacuum stabilizes (valve opens) below0.8 kPa (6 mmHg, 0.2 in.Hg) or above 2.1 kpa(16 mmHg, 0.6 in.Hg), install a new valve and retest.Move the vacuum pump hose from the vacuum fit-ting to the pressure fitting. and move the vacuumgauge hose from the vacuum side to the pressure
side as shown.
Slowly pressurize the vapor line while watching thegauge.
The pressure should stabilize momentarilv above1.0 kPa (8 mmHg, 0.3 in.Hg).a lf the pressure momentarily stabilizes (valve
opens) above 1.0 kPa (8 mmHg. 0.3 in.Hg), thevalve is OK.. lf the pressure stabilizes below ,|.0 kpa {g mmHg.0.3 in.Hg), install a new valve and retest.
T-FITTING
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