Dtc Troubleshooting - Honda 2004 Odyssey Service Manual

DTC Troubleshooting

DTC P0451 '99-00, '02-04 Models:
Sensor Range/Performance Problem
Special Tools Required
Vacuum Pump/Gauge, 0 30 in.Hg A973X-041-XXXXX
NOTE: Information marked with an asterisk ( ) applies
to '02-04 models.
1. Remove the fuel fill cap.
2. Turn the ignition switch ON (II).
3. Monitor FTP sensor voltage with the HDS, or
measure voltage between PCM connector
terminals A29 and C18.
PCM CONNECTORS
A (32P)
FTP (LT GRN)
Wire side of female terminals
Is there about 2.5 V ?
YES Go to step 4.
NO Replace the FTP sensor.
4. Turn the ignition switch OFF.
5. Disconnect the hose between the EVAP two way
valve and the FTP sensor at the EVAP two way
valve end.
FTP
C (31P)
SG2 (GRN/BLK)
SG2 (GRN/YEL)*
6. Connect a vacuum pump to the open end of the
hose.
A973X-041-XXXXX
7. Turn the ignition switch ON (II).
8. Monitor FTP sensor voltage with the HDS, or
measure voltage between PCM connector
terminals A29 and C18, and slowly squeeze the
vacuum pump one stroke at a time.
9. The voltage should drop smoothly from about 2.5 V
down to about 1.5 V. Stop applying vacuum when
the voltage drops to about 1.5 V or damage to the
FTP sensor may occur.
PCM CONNECTORS
A (32P)
FTP (LT GRN)
Wire side of female terminals
Does the voltage drop to about 1.5 V and hold?
YES Check for misrouted, leaking, or broken FTP
sensor vacuum lines. If the vacuum lines are OK,
substitute a known-good PCM and recheck (see
page 11-5). If the symptom/indication goes away,
replace the original PCM.
NO Replace the FTP sensor.
C (31P)
SG2 (GRN/BLK)
SG2 (GRN/YEL)*
11-261