Page 557 of 2189

Emission Control System
Evaporative Emission {EVAP) Controls (cont'dl
\J
tF1456-l
tP14sz-l
EVAPCONTROLCANISTERVENTSHUTVALVE
O.RINGReplace.
EVAPCONTROLCANISTER
ECM/PCM CONNECTOR A I32PI
(To page 11'289)
'99 - 00 modols except Dl6Y5 engine with M/T:
The scan tool indicates Diagnostic Trouble Code (DTC) P1456: Evaporative Emission (EVAP) control system leak
detected (fuel tank svstem).
The scan tool indicates Diagnostic Trouble Code (DTC) P1457: Evaporative Emission (EVAP) control system leak
detected (EVAP control canister system).
Possible Cause
. Fuel fill cap
. Vacuum Connections
. FuelTank
. EVAP Control Canister Vent Shut Valve
. EVAP Control Canister Vent Shut Valve Circuit
. EVAP Purge Control Solenoid Valve
o EVAP Purge Control Solenoid Valve Circuit
. EVAP Bypass Solenoid Valve
0 -30 in,Hg
. EVAP Bypass Solenoid Valve Circuit
. Fuel Tank Pressure Sensor
. Fuel Tank Pressure Sensor Circuir
. EVAP Control Canister
. ORVR vent shut valve
. ORVR vapor recirculation valve
. Throttle Body
Troubleshooting Flowchart
VACUUMPUMP/GAUGE,A973X - oal -
xxxxx
T-t
t\
The MIL has been reported on.DTC P1456 o. P1457 is stored.
Check the EVAP cont.ol canistervent shul valve:1. Disconnect the vacuum hosefrom the EVAP three wayvalve and connect a vacuumpump to the hose.2. Remove the EVAP controlcanister vent shut valve fromtne canrster.3. Turn the ignition switch ON (ll).
4. Apply vacuum to the hose.Check for a short in the wiro(VSV linel:Disconnect the 2P connector fromthe EVAP control canister ventDoes the vaive hold vacuum?
RoDair 3hort in the wire botwe€nthe EVAP control canilter ventshut valve and the ECM/PCM{A4t.
Does the valve hold vacuum?Check the EVAP cont.ol canisterv€nl shut valve:1. Turn the ignition switch OFF.2. Connect ECM/PCM connectorterminal A4 to body groundwith a jumper wire.3. Turn the ignition switch ON (ll).
4. Apply vacuum to the hose.
Reolace the EVAP control canis-ter veni shut valve.
Does the valve hold vacuum?
Wire side of female terminals
11-288
lTo page 11-289)
Page 558 of 2189

\
EVAP CONTROLCANISTER VENT SHUTVALVE 2P CONNECTOR IC141I
Wire side of temale terminals
ECM,/PCM CONNECTORS
tG1IBLK/WHT}
A973X -
0/r1 - XXXXX
Wire side of femaletermrnats
\
?,T-t
fl
VACUUMPUMP/GAUGE, 0 -30 in.Hg
\(cont'd)
11-289
{From page l1 288}
{To page 11-290)
Ch€ck the vac[um when cold:1, Disconnect the vacuum hoseshown from the EVAP controlcanister and connect a vacuumgauge to the hose.2. Start the engine and allow it
to idle.NOTEi Engine coolant temperature must be below 154"F(68'C) or Ay'C switch OFF.3. Ouickly raise the engine speedto 3,000 rpm.
(From page 11-288)
Check for an open in tha wire(lGt linol:1. Turn the ignition switch OFF.2. Disconnect the 2P connectorfrom the EVAP control canis-ter vent shut valve.3. Turn the ignition switch ON lll).4. Measure voltage between theEVAP control canister vent shut
valve 2P connector terminalNo.2 and bodyground.
Repair open in the wire betweenthe EVAP control canister ventshut valve .nd the No. 15 ALTER-NATOR SP SENSOR {7.5 A)fu3e.
ls there battery voltage?
Ch€d( for an op€n in the wiie IVSVlinel:1. Turn the ignition switch OFF.
2. R€connect the 2P connectorto the EVAP control canistervent shut valve,3. Turn the ignition switch ON (ll).
4. Measure vo ltage betweenECM/PCM connector termi-nals A4 and 82.
Repair open in the wire bctweenthe EVAP control canistor ventshut valve and lhe ECM/PCM{44t.
ls there battery voltage?
Rcolaco tho EVAP control canis.t6r vent shut valvo.
a t32P)
-
Page 559 of 2189

Emission Control System
Ch€ck the EVAP purge controlsolenoid valv6:1. Disconnect the 2P connectorfrom the EVAP purge controlsolenoid valve.2. Ouickly raise the engine speedto 3,000 rpm.
Insped vacuum hose routing.lf OK. roplace the EVAP purge
control solonoid valve.
Chock tor r short in the wir€
{PCS line):1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P).
3- Check tor continuity betweenthe EVAP purge control sole-noid valve 2P connector termi-nal No. 2 and body ground.
Check the vacuum when hot:1. Turn the ignition switch OFF.2. Block the rear wheels and setthe parking brake.3. Jack up the lront of the vehi-cle and support it with safetystands.4. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutrali until
the radiator fan comes on, thenlet it idle.5. Check for vacuum at the vac-uum hose with transmissionin gear (A/T in E position,
lvl/T in 1st gear) after startingthe engine.6. Ouickly raise the engine speedto 3,000 rpm.
Rooair shoft in the wire belwegnthe EVAP pulg6 control solenoidvalvs and tho ECM/PCM {A61.ls there continuity?
Substitute a known-good ECM/PCM and rech6ck. lt 3ymptom/indicrtion 90e3 rway, r6plac6 th€o.iginal ECM/FCM.
Check th€ EVAP purge controlsolenoid valve:1. Turn the;gnition switch OFF.2. Disconnect the 2P connectorfrom the EVAP purge controlsolenoid valve and warm itup to normal operating tem-perature again if necessary.3. Start the engine.4- At the harness side, measurevoltage between the EVAPpurge control solenoid valve2P connector terminal No. 1and No.2 with the transmis-sion in gear {A/T in E posi-tion, M/T in lst geari.
In3pect vacuum hoae routing.lf OK, repl.ce EVAP purge con-trol solonoid valve.ls there battery voltage?
Chock for an open in the wire(lG1 lina):At the harnoss side, measure volt-age beNveen the EVAP purge con-trol solenoid valve 2P connectorterminal No. 1 and body ground.
Repair open in the wire b€lwe€nEVAP purge contrl 3olenoid valv6and lhe No. 15 ALTERNATOR SPSENSOR 17.5 A, fu3e.
ls there battery voltage?
Evaporative Emission (EVAPI Controls (cont'dl
(From page 11-289)
(To page 11-291)
11-290
IJ
EVAP PURGE CONTROL SOLENOIDVALVE 2P CONNECTOR IC114I
PCS
IRED/YEL)
temaletermrnars
of
PCS(RED/YEL)
tGlIBLK/YEL)
{To page 11 291)
Page 560 of 2189

IECM/PCM CONNECTOR
I
EVAP TWO WAYVALVE
Wire side oftemaleterminals
FUELTANK
(cont'd)
11-291
tn
VACUUMPUMP/GAUGE,0 - 30 in Hs
A973X - 041 -
xxxxx
(From page l1 290)
Check the EVAP two way valve:
See EVAP two way valve test (see
page 11-295).
Roplace the EVAP two way valve
Check the EVAP bypa$ solenoid
1. Remove the fuel tank (see
page 11-242J.2. LiIt up the fuel tank with a
transmission iack, and connect
the fuel tank pressure sensor
sub harness 6P connector to
the access panel side connec_
tor,3. Disconnect the vacuum hosefrom the EVAP two way valveand connect a vacuum PumPto the hose,4. Turn the ignition switch ON (ll)
5. Apply vacuum to the hose.
(To page 11 292)
(From page 11-290)
Check for an open in the wire
{PCS lin6):1. Turn the ignition switch OFF
2. Reconnect the 2P connector to
the EVAP purge control sole-
3. Turn the ignition switch ON {ll).4. Measu re voltage betweenEClr/PCM connector terminals
A6 and 82.
Ropair open in the wire betweenthe EVAP purge Gontrol solenoidvrlve and th6 ECM/PCM lA6lls there battery voltage?
Substitute a known-good ECM/
PCM rnd re{61. lf symptom/indi'
cation goes away, rePlace the
oiiginal ECM/PCM.
Page 561 of 2189

Emission Control System
Evaporative Emission (EVAPI Gontrols (cont'd)EVAP BYPASSSOLENOID VALVEY
(From page l1'291)
Check for a short in the wire{2WBS linel:Disconnect the 2P connector {romthe EVAP bypass solenoid valve.
Does the valve hold vacuum?
Repair short in the wire betweenEVAP bypass solenoid velve andrhe ECM/PCM {A3).
Ooes the valve hold vacuum?
Check the EVAP bvpr$ 3olenoid
1. Turn the ignition switch OFF.2. Connect ECM/PCM connectorterminal A3 and body groundwith a jumper wire.3. Turn the ignition switch ON (ll).Ch€ck lor an op.n in the wirellcl linol:1. Turn the ignition switch OFF.2. Disconnect the 2P connectorfrom the EVAP bypass sole-noid valve.3. Turn the ignition switch ON (lll.
4, Measure voltage between theEVAP bypass solenoid valve2P connector terminal No. 1and body ground.
Does the valve hold vacuum?
Repair open in the wir6 b€tw€€nEVAP purg6 control 3olanoid valveand the No. 15 ALTERNATOR SPSENSOR {7.5 A) Iuse.
Wire side ol female terminals
EVAP SYPASS SOLENOIOVALVE 2P CONNECTOR IC793}
tG1{BLK/WHT)
Wire side offemaleterminals
{To page 11 293)
11-292
(To page 11 293i
Page 562 of 2189
I
\
\l
(From page 11-292i
Chock the tollowing parts tolleakage to aimosphero, and
ropaii or replaco if necess6.y:. fuel fill cap. fuel tank. fuel v.por pipe. EVAP two way valve. EVAP bypas solonoid valve. tuel tank pre3suae sen3or. EVAP control cankter. EVAP control canisier veni3hut valve. EVAP purge conttol solenoid
. ORVR vent 3hut valve. ORVB vaoor recirculation valve. vacuum hoses tnd connactions
(From page 11 292)
Check toi an opon in the wiro(2wBS linol:1. Turn the ignition switch OFF.2. Reconnect the 2P connectorto the EVAP bypass solenoid
3. Turn the ignition switch ON (ll).
4. Measure voltage betweenECM/PCM connector terminals43 and 82.
Reprir opan in tho wire be(wean
th. EVAP byp.is solonoid valve
rnd rhe EcM/PcM (A31.ls there baftery voltage?
(cont'd)
11-293
Page 695 of 2189
Circuit Diagram and Terminal Locations -'96 - 98 Modols
IGNITIONSWiTCHtc1
IOCI( - UP CONTBOLSOTENOID VALVE A
LOCK-UPCONTSOTsoLtNoto valvE I
SIIIFT CONTFOL
sHrFrc0mioLSOLENOIDVATVE B
UI{EAR SOLENOIO
IGPl
IGP2
vcc2TPSsG2
14-17
Page 720 of 2189

PCM Terminal Voltage/Measuring Gonditions ('96 - 9g Models)
A/T Control System
The PCM terminal voltage and measuring conditions are shown for the connector terminals that relate to the A"/T controlsystem. The other PCM terminal voltage and measuring conditions are described in section I l.
A l32P) Conn€ctotB I25P) ConnectorC (31P)ConngctorD (16P)Connector
PCM CONNECTOR A I32P}
Terminal NumborSignalDcacriptionMoasuring Conditions/Te.minal Voltage
A1 to A8- see section 1 I -
A9LG1Ground
A10PG1Grou nd
A11IGPlPower supply systemWith ignition switch ON (ll): 8attery voltage
With ignition switch OFF: 0 V
412 to A2l- see section I I -
Ground
423PG2Ground
A'24IG P2Power supply systemWith ignition switch ON (ll): Battery voltage
With ignition switch OFF: 0 V
A25 to A32- see section l1 -
PCM CONNECTOR B (25P}
Terminal NumberSignalDescriptionMeasuring Conditions/T6rminal Voltage
B1LS-Linear solenoid power supply
negative electrode
lgnition switch ON (ll): Pulsing signa.
82Linear solenoid power supplypositive electrode
lgnition switch ON (ll): Pulsing signal
SHAShitt control solenoid valve A
controlIn 2nd gear and 3rd gear in E, E position,
and in @, @ position: Battery voltage
In lst gear and 4th gear in E. E position: 0 V
B4LCBLock-up control solenoid valve B
control
When full lock-up: Battery voltage
When half lock-up: Pulsing signal
B5LCALock-up control sol€noid valve AcontrolWhen lock-up is ON: Battery voltage
With no lock-up: 0 V
86 to 87Not used
B8ATP D3IVT g6ar position switch @ posi-
tion signal input
lnEposition; OV
In other than E position: Battery voltage
Bg to 810Not used
\-
14-42