Toyota Tundra (2015 year). Manual — part 1566
INSPECTION PROCEDURE
Refer to the EVAP System
.
MONITOR DESCRIPTION
The two monitors, Key-Off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The Key-Off monitor is
initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is turned off. The purge flow
monitor runs while the engine is running.
KEY-OFF MONITOR
5 hours* after the ignition switch is turned off, the leak detection pump creates negative pressure
(vacuum) in the EVAP system. The ECM monitors for leaks and actuator malfunctions based on the EVAP
pressure.
HINT:
*: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned
off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition
switch is turned off, the monitor check starts 2.5 hours later.
SEQUENCE
OPERATION
DESCRIPTION
DURATION
-
ECM activation
Activated by soak timer 5, 7 or 9.5 hours after ignition
switch turned off.
-
A
Atmospheric
pressure
measurement
Vent valve turned OFF (vent) and EVAP system
pressure measured by ECM in order to register
atmospheric pressure.
If pressure in EVAP system not between 70 kPa-a and
111 kPa-a (525 mmHg-a and 833 mmHg-a), ECM
cancels EVAP system monitor.
60 seconds
B
First reference
pressure
measurement
In order to determine reference pressure, leak
detection pump creates negative pressure (vacuum)
through reference orifice and then ECM checks if leak
detection pump and vent valve operate normally.
360
seconds*1
300
seconds*2
C
EVAP system
pressure
measurement
Vent valve turned ON (closed) to shut EVAP
system.
Negative pressure (vacuum) created in
EVAP system, and EVAP system pressure
then measured.
Write down measured value as it will be
used in leak check.
If EVAP pressure does not stabilize within
15 minutes*1, ECM cancels EVAP system
monitor.
If EVAP pressure does not stabilize within
30 minutes*2, ECM cancels EVAP system
monitor.
15
minutes*1,
*3
30
minutes*2,
*3
D
Purge VSV
monitor
Purge VSV opened and then EVAP system pressure
measured by ECM.
Large increase indicates normality.
10 seconds
E
Second reference
pressure
measurement
After second reference pressure measurement, leak
check performed by comparing first and second
reference pressure.
If stabilized system pressure higher than second
reference pressure, ECM determines that EVAP
system leaking.
60 seconds
3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0441; Evap...
SEQUENCE
OPERATION
DESCRIPTION
DURATION
-
Final check
Atmospheric pressure measured and then monitoring
result recorded by ECM.
-
HINT:
In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP
system. The EVAP system pressure is then measured by the ECM using the canister pressure
sensor. If the stabilized system pressure is higher than [second reference pressure x 0.2], the
ECM interprets this as the purge VSV (Vacuum Switching Valve) being stuck open. The ECM
illuminates the MIL and stores the DTC (2 trip detection logic).
a.
3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0441; Evap...
HINT:
*1: for 100 L (26.4 US gal) Fuel Tank
*2: for 144 L (38 US gal) Fuel Tank
Purge VSV stuck closed
In operation D, the canister pressure sensor measures the EVAP system pressure. The pressure
measurement for the purge VSV monitor is begun when the purge VSV is turned ON (open)
increase, the ECM interprets this as the purge VSV being stuck closed. The ECM illuminates the
MIL and stores the DTC (2 trip detection logic).
b.
PURGE FLOW MONITOR
for 100 L (26.4 US gal) Fuel Tank:
3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0441; Evap...
for 144 L (38 US gal) Fuel Tank:
The 1st monitor
While the engine is running and the purge VSV is ON (open), the ECM monitors the purge flow by
measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd
monitor.
The 2nd monitor (for 100 L (26.4 US gal) Fuel Tank)
The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the
pressure is less than 0.4 kPa-g (3 mmHg-g), the ECM interprets this as the purge VSV being stuck closed,
and illuminates the MIL and stores DTC P0441 (2 trip detection logic).
The 2nd monitor (for 144 L (38 US gal) Fuel Tank)
The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the
pressure is less than 0.15 kPa-g (1.125 mmHg-g), the ECM interprets this as the purge VSV being stuck
closed, and illuminates the MIL and stores DTC P0441 (2 trip detection logic).
Atmospheric pressure check:
In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after
Required Sensors/Components
Purge VSV and canister pump module
3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0441; Evap...
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