Toyota Tundra. Manual — part 1245

HINT:

The vent valve is built into the canister pump module.

DESCRIPTION

The description can be found in the EVAP (Evaporative Emission) System (See DESCRIPTION ).

INSPECTION PROCEDURE

Refer to the EVAP SYSTEM .

MONITOR DESCRIPTION

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.

MONITOR DESCRIPTION CHART

P2420

Vent valve
stuck open
(vent)

Following condition met
during key-off EVAP
monitor:



EVAP pressure
change when vent
valve closed (ON)
less than 0.3 kPa-g
(2.25 mmHg-g)



Canister pump module
(Reference orifice, leak
detection pump, vent
valve)



Connector/wire harness
(Canister pump module
- ECM)



ECM

While
ignition
switch OFF

2 trip

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

Vent valve turned ON (closed) to shut EVAP system.

2008 Toyota Tundra

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

Fig. 208: System Pressure Measurement Diagram

P2420: Vent valve stuck open (vent)

In operation C, the vent valve turns ON (closes) and the EVAP system pressure is then measured by the ECM
using the canister pressure sensor to conduct an EVAP leak check. If the pressure does not increase when the
vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL
and sets the DTC.

C

EVAP system
pressure
measurement

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. 209: EVAP Pressure Malfunction Diagram - Vent Valve Stuck Open (Vent)

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

Required Sensors/Components

Purge VSV and canister pump module

Frequency of Operation

Once per driving cycle

Duration

Within 2 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

Purge VSV

Not operated by scan tool

Vent valve

Not operated by scan tool

2008 Toyota Tundra

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

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

DTC P2431 SECONDARY AIR INJECTION SYSTEM AIR FLOW/PRESSURE SENSOR CIRCUIT
RANGE/PERFORMANCE BANK 1; DTC P2432 SECONDARY AIR INJECTION SYSTEM AIR
FLOW/PRESSURE SENSOR CIRCUIT LOW BANK 1; DTC P2433 SECONDARY AIR INJECTION
SYSTEM AIR FLOW/PRESSURE SENSOR CIRCUIT HIGH BANK 1; DTC P2436 SECONDARY AIR
INJECTION SYSTEM AIR FLOW/PRESSURE SENSOR CIRCUIT RANGE/PERFORMANCE BANK
2; DTC P2437 SECONDARY AIR INJECTION SYSTEM AIR FLOW/PRESSURE SENSOR CIRCUIT
LOW BANK 2; DTC P2438 SECONDARY AIR INJECTION SYSTEM AIR FLOW/PRESSURE
SENSOR CIRCUIT HIGH BANK 2

DESCRIPTION

The Secondary Air injection (AIR) system consists of an air pump, the Air Switching Valve (ASV), a pressure
sensor, the Air Injection Control Driver (AID) and the ECM. For a short time after cold engine starts, the AIR
system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The
secondary air is supplied by the air pump and is pumped to the exhaust port through the ASV.

The AID drives the ASV and the air pump according to command signals transmitted by the ECM. The pressure
sensor detects the pressure in the secondary air passage when the AIR system is ON and OFF, and transmits a
pressure signal to the ECM.

The AID is not only equipped to drive the pump and valve, but also with a diagnosis function to detect
malfunctions in the AIR system circuit.

HINT:

As a large current is required to drive the air pump and ASV, an AID is installed to this system.

Leak detection pump

Not operated by scan tool

Both of following conditions met before key off

Conditions 1 and 2

1. Duration that vehicle 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)

EVAP pressure change after EVAP canister vent valve ON

Less than 0.3 kPa-g (2.25 mmHg-g)

2008 Toyota Tundra

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