Toyota Sequoia (2005). Manual — part 120
A23486
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec
Negative
ON
ON
Sequence
Time
A
10
sec
60
Within 15 minutes
sec
ON
First 0.02 inch
B
C
D
P0455
ON: Open
OFF: Closed
OFF: Vent
ON: Closed
10
Standard
sec
60
E
P0456
OK
EVAP Pressure when EVAP system Leaks:
Leak Pressure
Second 0.02 inch
Standard x 0.2
–
DIAGNOSTICS
ENGINE
DI–275
469
(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).
MONITOR STRATEGY
R l t d DTC
P0455
Gross leak detected
Related DTCs
P0456
Very small leak (0.020 inch hole) detected
Required sensors/components
Purge VSV, Pump module
Frequency of operation
Once per driving cycles
Duration
Within 15 min. (varies with amount of fuel in tank)
MIL operation
2 driving cycles
Sequence of operation
None
TYPICAL ENABLING CONDITIONS
It
Specification
Item
Minimum
Maximum
The monitor will run whenever these
DTCs are not present
See page
Following values are when atmospheric is
760 mmHg (100 kPa)
–
EVAP key–off monitor runs when all of the
following conditions met:
–
DI–276
–
DIAGNOSTICS
ENGINE
470
Atmospheric pressure
525 to 825 mmHg (70 to 110 kPa)
Battery voltage
10.5 V
–
Vehicle speed
–
4 km/h (2.5 mph)
Ignition switch
OFF
Engine condition
Not running
Time after engine stopped
5 hours
FTP sensor malfunction (P0450, P0452,
P0453)
Not detected
Purge VSV
Not operated by scan tool
Vent valve
Not operated by scan tool
Leak detection pump
Not operated by scan tool
Both of the following conditions are met
before IG switch OFF
Condition 1 and 2
1. Duration that vehicle is driven
5 min.
–
2. Purge flow
Executed
ECT
4.4 to 35
°
C (40 to 95
°
F)
IAT
4.4 to 35
°
C (40 to 95
°
F)
Example of re–start time
–
First time
7 hours
Second time
9 hours and 30 min.
Key–off monitor sequence
1 to 8
1. Atmospheric pressure
–
Next sequence is run if following condition
set
–
Atmospheric pressure change for 10 sec.
–
2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure
–
Next sequence is run if all of following
conditions set
Condition 1, 2 and 3
1. FTP when 4 sec. after reference pres-
sure measurement
–
–7.5 mmHg (–1 kPa)
2. Reference pressure
–36.38 to –7.93 mmHg (–4.85 to –1.057 kPa)
3. Reference pressure
Saturated
3. Vent valve stuck closed check
–
Next sequence is run if following condition
set
–
FTP change for 10 sec. after vent valve
ON (closed)
2.25 mmHg (0.3 kPa)
–
4. Vacuum introduction and leak
–
Next sequence is run if both of following
conditions set
Condition 1 and 2
1. Vacuum introduction time
–
15 min.
2. FTP
FTP was saturated
5. Purge VSV stuck closed check
–
Next sequence is run if following condition
set
–
FTP change for 10 sec. after purge VSV
ON (open)
2.25 mmHg (0.3 kPa)
–
–
DIAGNOSTICS
ENGINE
DI–277
471
6. Second reference pressure measure-
ment
–
Next sequence is run if all of following
conditions set
Condition 1, 2, 3 and 4
1. FTP when 4 sec. after reference pres-
sure measurement
–
–7.5 mmHg (–1 kPa)
2. Reference pressure
–36.38 to –7.93 mmHg (–4.85 to –1.057 kPa)
3. Reference pressure
Saturated
4. Reference pressure difference between
first and second
–
5.25 mmHg (0.7 kPa)
7. Leak check
–
Next sequence is run if following condition
set
–
FTP when vacuum introduction was com-
plete
–
Second reference pressure
8. Atmospheric pressure
–
Monitor is complete if following
–
Atmospheric pressure difference between
sequence 1 and 8
–
2.25 mmHg (0.3 kPa)
TYPICAL MALFUNCTION THRESHOLDS
Detection Criteria
Threshold
Small leak (0.020 inch) malfunction detection:
FTP when vacuum introduction was compleat
Between 1 and 2
Condition 1.
Higher than second reference pressure
Condition 2.
Lower than reference pressure x 0.2
Gross leak detection:
FTP when vacuum introduction was compleat
Higher than reference pressure x 0.2
MONITOR RESULT (MODE 06 DATA)
Refer to page
for detailed information on Monitor Result.
INSPECTION PROCEDURE
Refer to the EVAP Inspection Procedure (see page
P22487
Vehicle Speed
Sensor
Combination
Meter
ECM
4–pulse
4–pulse
DI–278
–
DIAGNOSTICS
ENGINE
472
DTC
P0500
Vehicle Speed Sensor ”A”
DTC
P0503
Vehicle Speed Sensor ”A” Intermittent/
Erratic/High
CIRCUIT DESCRIPTION
The No.1 vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is ro-
tated by the transmission output shaft via the driven gear. After this signal is converted into a more precise
rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted
to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.
DTC No.
Proceed to
DTC Detection Condition
Trouble Area
P0500
Step 1
No vehicle speed sensor sig-
nal to ECM under following
conditions: (2 trip detection
logic)
Vehicle is being driven
Combination meter
Open or short in vehicle speed sensor circuit
Vehicle speed sensor
ECM
P0503
Intermittent problem in the ve-
hicle speed sensor circuit
ECM
MONITOR DESCRIPTION
The ECM assumes that the vehicle is driven when the park/neutral position switch is OFF and it has been
over 4 sec. since the actual vehicle speed was 9 km/h (6 mph) or more.
If there is no signal from the vehicle speed sensor when these conditions are satisfied, the ECM concludes
that there is a fault in the vehicle speed sensor. The ECM will turn on the MIL and a DTC is set.
DID8B–01
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