Dtc Pl456: Evap Control (Fuel Tank System) - Honda EP3 Service Manual

DTC Pl456: EVAP Control
(Fuel Tank Svstem)
System Leakage
The fuel system is designed to allow specified
maximum vacuum and pressure conditions. Do not
deviate from the vacuum and pressure tests as
indicated in these procedures. Excessive pressure/
vacuum would damage the EVAP components or cause
eventual fuel tank failure.
Special Tools Required
Vacuum Pump/Gauge, 0-30 in. Hg A973X-041-XXXXX
This is a two-trip code. Once cleared, it cannot be
reproduced in one trip. Also, cenain specific driving
and ambient conditions must occur before the ECM will
complete the system checks. Additional test drives may
still not meet the specific conditions needed to
reproduce the code.
Follow these troubleshooting procedures carefully to
ensure the integrity of the system and to confirm the
cause of the problem or code.
NOTE: Fresh fuel has a higher volatility that creates
greater pressure/vacuum. The optimum condltlon for
testing is fresh fuel, and must be less than a full tank. lf
possible, to assist in leak detection, add 1 gallon of
fresh fuel to the tank (as long as it will not fill the tank).
just before starting these procedures.
Fuel Fill Cap Check
1. Check the fuel fill cap (the cap must say "lf not
tightened 3 clicks check engine light may come
o n " ) .
ls the proper luel till cap installed and properly
tightened?
YES Go to step 2.
NO- Replace or tighten the cap.I
2. Check the fuel fill cap seal.
ls the tuel fill cap seal missing or damaged?
Y E S - R e p l a c e t h e f u e l f i l l c a p . I
N O T h e f u e l f i l l c a p i s O K . G o t o s t e p 3 .
EVAP Canister Purge Valve Test
3. Disconnect the vacuum hose from the EVAP
canister purge valve (A), and connect a vacuum
oumo to the hose.
A973X-041-XXXXX
T u r n t h e i g n i t i o n s w i t c h O N ( l l ) .
Apply vacuum to the hose.
Does the valve hold vacuum?
YES-The EVAP canister purge valve is OK. Go to
s t e p 1 1 .
NO-Go to step 6.
Turn the ignition switch OFF.
Disconnect the EVAP canister purge valve 2P
connecror.
5 .
7 .
{cont'd)
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