Toyota Tundra 2005 Service - Repair - Maintenance page 971

DI−698
(a) P0455: EVAP (Evaporative Emission) gross leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP
system pressure is measured. If the stabilized system pressure is higher than [second 0.02 inch leak pres-
sure standard x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large
leakage, illuminates the MIL and sets the DTC (2 trip detection logic).
(b) P0456: EVAP very small leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP
system pressure is measured. If the stabilized system pressure is higher than second 0.02 inch leak pres-
sure standard, the ECM determines that the EVAP system has a small leakage, illuminates the MIL and sets
the DTC (2 trip detection logic).
EVAP Pressure when EVAP system Leaks:
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Negative
First 0.02 inch
Leak Pressure
Standard
Sequence
Time
MONITOR STRATEGY
R l t d DTC Related DTCs
Required sensors/components
Frequency of operation
Duration
MIL operation
Sequence of operation
TYPICAL ENABLING CONDITIONS
Item It
The monitor will run whenever these
DTCs are not present
Atmospheric pressure
Battery voltage
Vehicle speed
Ignition switch
DIAGNOSTICS
A B
10 60
sec sec
Purge VSV, Pump module
Once per driving cycles
Within 15 min. (varies with amount of fuel in tank)
2 driving cycles
None
− ENGINE (2UZ−FE)
ON
ON
P0455
P0456
OK
C
Within 15 minutes
P0455
P0456
Specification
Minimum
See page
70 to 110 kPa (525 to 825 mmHg)
10.5 V
−
ON
D E
60
10
sec
sec
Gross leak detected
Very small leak (0.020 inch hole) detected
Maximum
DI−437
−
2.5 mph (4 km/h)
OFF
ON: Open
OFF: Closed
ON: Closed
OFF: Vent
Second 0.02 inch
Leak Pressure
Standard x 0.2
A23486