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EMISSION CONTROL SYSTEMS
SR
EVAPORATIVE E M I S S I O N C O N T R O L S
INDEX
p a g e
D E S C R I P T I O N A N D O P E R A T I O N
C R A N K C A S E V E N T I L A T I O N S Y S T E M
11
D U T Y C Y C L E E V A P P U R G E S O L E N O I D
11
E V A P C A N I S T E R A N D L E A K D E T E C T I O N
P U M P
10
E V A P O R A T I O N C O N T R O L S Y S T E M
10
L E A K D E T E C T I O N P U M P
11
P R E S S U R E - V A C U U M F U E L F I L L E R T U B E C A P . 11
V E H I C L E E M I S S I O N C O N T R O L I N F O R M A T I O N
L A B E L
11
p a g e
D I A G N O S I S A N D T E S T I N G
C R A N K C A S E V E N T I L A T I O N S Y S T E M
I N S P E C T I O N
12
L E A K D E T E C T I O N P U M P
12
V A C U U M S C H E M A T I C . .
12
R E M O V A L A N D I N S T A L L A T I O N
D U T Y C Y C L E E V A P P U R G E S O L E N O I D
. .
13
E V A P C A N I S T E R
. 13
L E A K D E T E C T I O N P U M P ( L D P )
14
DESCRIPTION A N D OPERATION
EVAPORATION CONTROL SYSTEM
The evaporation control system prevents the emis-
sion of fuel t a n k vapors into the atmosphere. When
fuel evaporates i n the fuel tank, the vapors pass
through vent hoses or tubes to an activated carbon
filled evaporative canister. The canister temporarily
holds the vapors. The Powertrain Control Module
(PCM)
allows intake
manifold vacuum
to
draw
vapors into the combustion chambers d u r i n g certain
operating conditions.
A l l engines use a d u t y cycle purge system. The
P C M controls vapor flow by operating the d u t y cycle
EVAP purge solenoid. Eefer to D u t y Cycle EVAP
Purge Solenoid i n this section.
N O T E : T h e e v a p o r a t i v e s y s t e m u s e s s p e c i a l l y m a n -
u f a c t u r e d h o s e s , t h e y n e e d r e p l a c e m e n t , o n l y u s e
f u e l r e s i s t a n t h o s e . A l s o t h e h o s e s m u s t b e a b l e t o
p a s s a n O z o n e c o m p l i a n c e t e s t .
EVAP CANISTER AND LEAK DETECTION PUMP
A l l vehicles use a sealed, maintenance free, char-
coal filled EVAP canister. The canister mounts to the
radiator support behind the front fascia (Fig. 1).
Fuel t a n k pressure vents into the canister. The
canister
temporarily holds the
fuel
vapors
u n t i l
Fig.
1 EVAP
Canister
and Leak Detection
Pump
intake manifold vacuum draws t h e m into the induc-
t i o n
system.
The P C M regulates vapor
flow
by
switching the EVAP purge solenoid On and Off. The
EVAP purge solenoid supplies the vacuum signal to
the EVAP canister. The P C M purges the canister at
predetermined intervals and engine conditions.
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Troubleshooting
