Honda 2004 Odyssey Service Manual page 582

Vacuum Hoses and Connections Test
30. Tighten the fuel cap 3 ''clicks'', then monitor the
fuel tank pressure readings with the HDS.
31. Start the engine. Let the engine idle for 5 minutes.
32. Check the fuel tank pressure sensor readings.
B
C
A
Is the reading above 0.5 kPa ( 0.16 in.Hg, 4 mmHg)
pressure or below 0.5 kPa ( 0.16 in.Hg, 4 mmHg)
vacuum?
YES Substitute a known-good PCM and retest
(see page 11-5). If the symptom/indication goes
away, replace the original PCM.
NO Check these parts for leaks:
• Fuel tank (A)
• Fuel fill cap (B)
• Fuel fill pipe (C)
• EVAP two way valve (D)
• FTP sensor (E)
– Repair or replace any leaking parts.
E
D
DTC P1456 '01 Model:
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 DTC P0461 first, then recheck for
DTC P1456.
NOTE: If DTC P0461 is stored at the same time as DTC
P1456, troubleshoot DTC 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 check 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 System
(cont'd)
11-273 11-273