Toyota Tundra. Manual — part 1214

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.

MONITOR DESCRIPTION CHART

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 110
kPa-a (525 mmHg-a and 825 mmHg-a), ECM cancels EVAP
system monitor.

10

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.

60

seconds

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, ECM
cancels EVAP system monitor.

15

minutes

(1)

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

-

Final check

Atmospheric pressure measured and then monitoring result
recorded by ECM.

-

(1)

If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 161: Monitor Description - EVAP System Pressure Measurement

a. P0455: EVAP gross leak

In operation C, the leak detection 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 reference
pressure 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 leak detection pump creates negative pressure (vacuum) in the EVAP system and the
EVAP system pressure is measured. If the stabilized system pressure is higher than the second reference
pressure, the ECM determines that the EVAP system has a small leakage, illuminates the MIL and sets
the DTC (2 trip detection logic).

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 162: Monitor Description When EVAP Very Small Leak

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

P0455 (pattern A), P0456:

TYPICAL ENABLING CONDITIONS

Required Sensors/Components

Purge VSV and canister pump module

Frequency of Operation

Once per driving cycle

Duration

Within 15 minutes (varies with amount of fuel in tank)

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not present

None

EVAP key-off monitor runs when all of following conditions met -
Atmospheric pressure

70 to 110 kPa-a (525 to 825 mmHg-a)

Battery voltage

10.5 V or more

Vehicle speed

Below 4 km/h (2.5 mph)

Ignition switch

OFF

Time after key off

5 or 7 or 9.5 hours

Canister pressure sensor malfunction (P0451, P0452 and P0453)

Not detected

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

P0455 (pattern B)

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P0455: EVAP gross leak

TYPICAL MALFUNCTION THRESHOLDS

P0456: EVAP small leak

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

Purge VSV

Not operated by scan tool

Vent valve

Not operated by scan tool

Leak detection pump

Not operated by scan tool

Both of following conditions met before key off

Conditions 1 and 2

1. Duration that vehicle is driven

5 minutes or more

2. EVAP purge operation

Performed

ECT

4.4 to 35°C (40 to 95°F)

IAT

4.4 to 35°C (40 to 95°F)

Atmospheric pressure

70 to 110 kPa-a (525 to 825 mmHg-a)

Battery voltage

10.5 V or more

Vehicle speed

Below 4 km/h (2.5 mph)

Ignition switch

OFF

Canister pressure sensor malfunction (P0451, P0452 and 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 following conditions met before key off

Conditions 1 and 2

1. Duration that vehicle is driven

5 minutes or more

2. EVAP purge operation

Performed

ECT

4.4 to 40°C (40 to 104°F)

IAT

4.4 to 40°C (40 to 104°F)

EVAP pressure when vacuum introduction complete

Higher than reference pressure x 0.2

EVAP pressure when vacuum introduction
complete

Between reference pressure and reference pressure x
0.2

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra