Honda 2004 Odyssey Service Manual page 578

DTC P1456 '99-00 Models:
System Leakage (fuel tank system)
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
NOTE: If DTC P0461 is stored at the same time as DTC
P1456, troubleshoot P0461 first, then recheck for DTC
P1456.
This is a two trip code; once cleared, it cannot be
reproduced in one trip. Also, certain specific driving
and ambient conditions must occur before the PCM 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 will create
greater pressure/vacuum. The optimum condition for
testing is fresh fuel and less than a full tank of gas. If
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. It must say ''If not tightened
3 clicks engine light may come on.''
Is the correct f uel f ill cap installed and properly
tightened?
YES Go to step 2.
NO Replace or tighten the cap.
EVAP Control
2. Check the fuel fill cap seal.
Is the f uel f ill cap seal missing or damaged?
YES Replace the fuel fill cap (gray or black
colored cap).
NO The fuel fill cap is OK. Go to step 3.
EVAP Purge Control Solenoid Valve Test
3. Disconnect the vacuum hose from the EVAP purge
control solenoid valve (A), and connect a vacuum
pump to the hose.
A
4. Turn the ignition switch ON (II).
5. Apply vacuum to the hose.
Does the valve hold vacuum?
YES The EVAP purge control solenoid valve is OK.
Go to step 11.
NO Go to step 6.
6. Turn the ignition switch OFF.
7. Disconnect the EVAP purge control solenoid valve
2P connector.
A973X-
041-XXXXX
(cont'd)
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