Page 57 of 2000
ENGINE - 2AZ-FE ENGINE
00REG25Y
D13N22
Atmosphere
Purge VSV
(OFF)
ECMCanister Pump Module
Ve n t Va l v e
(OFF)
Leak Detection Pump
& Pump Motor
Canister
Pressure Sensor
Purge VSV
Vent Valve
Pump Motor
System PressureON (Open)
OFF (Close)
ON
OFF (Vent)
ON
OFF
Atmospheric Pressure
0.02 in. Leak Pressure
Atmospheric Pressure Measurement
P
M
EG-60
b. Atmospheric Pressure Measurement
1) When the ignition switch is turned OFF, the purge VSV and vent valve are turned OFF. Therefore,
the atmospheric pressure is introduced into the canister.
2) The ECM measures the atmospheric pressure through the signals provided by the canister pressure
sensor.
3) If the measurement value is out of standards, the ECM actuates the leak detection pump in order
to monitor the changes in the pressure.
Page 58 of 2000

ENGINE - 2AZ-FE ENGINE
00REG26Y
275TU48
Atmosphere
Purge VSV
(OFF)
ECMCanister Pump Module
Ve n t Va l v e
(OFF)
Leak Detection Pump
& Pump Motor
Canister Pressure
Sensor
Reference Orifice
Purge VSV
Vent Valve
Pump Motor
System PressureON (Open)
OFF (Close)
ON
OFF (Vent)
ON
OFF
Atmospheric Pressure
0.02 in. Leak Pressure
0.02 in. Leak Pressure Measurement
M
P
EG-61
c. 0.02 in. Leak Pressure Measurement
1) The vent valve remains OFF, and the ECM introduces atmospheric pressure into the canister and
actuates the leak detection pump in order to create a negative pressure.
2) At this time, the pressure will not decrease beyond a 0.02 in. leak pressure due to the atmospheric
pressure that enters through a 0.02 in. diameter reference orifice.
3) The ECM compares the logic value with this pressure, and stores it as a 0.02 in. leak pressure in its
memory.
4) If the measurement value is below the standard, the ECM will determine that the reference orifice
is clogged and store DTC (Diagnostic Trouble Code) P043E in its memory.
5) If the measurement value is above the standard, the ECM will determine that a high flow rate pressure
is passing through the reference orifice and store DTCs (Diagnostic Trouble Codes) P043F, P2401
and P2402 in its memory.
Page 59 of 2000

ENGINE - 2AZ-FE ENGINE
00REG27Y
275TU49
Purge VSV
(OFF)Atmosphere
ECMCanister Pump Module
Vent Valve
(ON)
Leak Detection Pump
& Pump Motor
Canister
Pressure Sensor
M
P
Reference Orifice
Va c u u m
Purge VSV
Ve n t Va l v e
Pump Motor
System PressureOFF (Close)
ON (Open)
ON
OFF (Vent)
ON
OFF
Atmospheric Pressure
0.02 in. Leak Pressure
EVAP Leak CheckP0455
P0456
Normal EG-62
d. EVAP Leak Check
1) While actuating the leak detection pump, the ECM turns ON the vent valve in order to introduce a
vacuum into the canister.
2) When the pressure in the system stabilizes, the ECM compares this pressure with the 0.02 in. leak
pressure in order to check for a leakage.
3) If the measurement value is below the 0.02 in. leak pressure, the ECM determines that there is no
leakage.
4) If the measurement value is above the 0.02 in. leak pressure and near atmospheric pressure, the ECM
determines that there is a gross leakage (large hole) and stores DTC P0455 in its memory.
5) If the measurement value is above the 0.02 in. leak pressure, the ECM determines that there is a small
leakage and stores DTC P0456 in its memory.
Page 60 of 2000
ENGINE - 2AZ-FE ENGINE
00REG28Y
275TU50 M
P
Atmosphere
Atmosphere
Purge VSV
(ON)
ECMCanister Pump Module
Vent Valve
(ON)
Leak Detection Pump
& Pump Motor
Canister
Pressure Sensor
Purge VSV Monitor
P0441
Normal
Purge VSV
Vent Valve
Pump Motor
System PressureON (Open)
OFF (Close)
ON
OFF (Vent)
ON
OFF
Atmospheric Pressure
0.02 in. Leak PressureEG-63
e. Purge VSV Monitor
1) After completing an EVAP leak check, the ECM turns ON (open) the purge VSV with the leak
detection pump actuated, and introduces the atmospheric pressure from the intake manifold to the
canister.
2) If the pressure change at this time is within the normal range, the ECM determines the condition to
be normal.
3) If the pressure is out of the normal range, the ECM will stop the purge VSV monitor and store DTC
P0441 in its memory.
Page 61 of 2000
ENGINE - 2AZ-FE ENGINE
01MEG03Y
275TU51
Repeat 0.02 in. Leak Pressure Measurement Atmosphere
Purge VSV
(OFF)
ECMCanister Pump Module
Ve n t Va l v e
(OFF)
Leak Detection Pump
& Pump Motor
Canister Pressure
SensorReference Orifice
Purge VSV
Ve n t Va l v e
Pump Motor
System PressureON (Open)
OFF (Close)
ON
OFF (Vent)
ON
OFF
Atmospheric Pressure
0.02 in. Leak Pressure
P0456
Normal
M
P
EG-64
f. Repeat 0.02 in. Leak Pressure Measurement
1) While the ECM operates the vacuum pump, the purge VSV and vent valve turn off and a repeat 0.02
in. leak pressure measurement is performed.
2) The ECM compares the measured pressure with the pressure during EVAP leak check.
3) If the pressure during the EVAP leak check is below the measured value, the ECM determines that
there is no leakage.
4) If the pressure during the EVAP leak check is above the measured value, the ECM determines that
there is a small leakage and stores DTC P0456 in its memory.
Page 62 of 2000

ENGINE - 2AZ-FE ENGINE
01NEG13Y
Generator
RegulatorB
DF
RLOECM
Various Electrical
Loads
Battery Current Sensor
Battery Temperature Sensor
Battery Voltage
Battery
Various Sensors and Switches
Throttle Position Sensor
Crankshaft Position Sensor
Accelerator Pedal Position
SensorEG-65
11. Charging Control
General
This system lowers the generated voltage when the vehicle is idling or is being driven at a constant speed,
and raises the generated voltage when the vehicle is decelerating. This reduces the load on the engine as
a result of the electric generation of the generator, thus contributing to the fuel economy of the engine.
During acceleration, this system regulates the generated voltage in order to place the amperage estimation
value close to the target value.
This control consists of the ECM, battery current sensor with a built-in battery temperature sensor,
generator, and various sensors and switches.
The ECM detects driving condition based on signals from various sensors and switches, and detects
charging condition based on signals from the generator, battery current sensor and battery temperature
sensor. Then the ECM outputs signals to the IC regulator to control the genetated voltage of the generator.
The ECM stops the charging control and the generator switches to normal power generation mode under
the following conditions:
Low battery capacity
Low or high battery temparature
Wipers operating or blower motor operating with tail lamp relay ON
System Diagram
Page 63 of 2000

ENGINE - 2AZ-FE ENGINE
258AS61 281EG86
Output
Voltage5 (V)
0
-100
Current+100 (A)
Characteristic of Current Sensor
288EG61C
(C) 60
Battery Temperature 0 Resistance(k
)
6 EG-66
Battery Current Sensor
Installed on the negative terminal of the battery, this sensor detects the amount of charging and discharging
amperage of the battery and sends signal to the ECM. Based on this signal, the ECM calculates the battery
capacity. A Hall IC is used for detecting the amount of charging and discharging amperage. The changes
that occur in the magnetic flux density in the core as a result of the charging and amperage of the battery
are converted and output as voltage.
Batter Temperature Sensor
The battery temperature sensor is built into the battery current sensor.
The battery characteristic (battery internal resistance) of taking in current for charging varies according
to battery electrolyte temperature. If the electrolyte temperature is too low or too high, the battery internal
resistance will increase, resulting in early deterioration. To prevent this, the battery temperature sensor
changes its resistance as shown below to detect the temperature.
Page 64 of 2000

ENGINE - 2AZ-FE ENGINE
Service Tip
To clear the DTC that is stored in the ECM, use a hand-held tester or disconnect the battery terminal
or remove the EFI fuse for 1 minute or longer.
EG-67
Fail-safe
Due to a failure in the battery current sensor or battery temperature sensor, the ECM may determine the
necessity of performing a fail-safe operation. Then, the ECM stops the charging control and the generator
switches to the normal power generation mode.
When the ECM detects a malfunction in a sensor, the ECM memorizes the DTC (Diagnostic Trouble Code).
The MIL (Malfunction Indicator Lamp) does not illuminate.
DTC Chart
DTC No.Detection ItemDTC No.Detection Item
P0516Battery Temperature Sensor
Circuit LowP1551Battery Current Sensor
Circuit Low
P0517Battery Temperature Sensor
Circuit HighP1552Battery Current Sensor
Circuit High
P0560System VoltageP1602Detection of Battery
P1550Battery Current Sensor
Circuit
12. Diagnosis
When the ECM detects a malfunction, the ECM makes a diagnosis and memorizes the failed section.
Furthermore, the MIL in the combination meter illuminates or blinks to inform the driver.
The ECM will also store the DTCs of the malfunctions. The DTCs can be accessed by the use of the
hand-held tester.
For details, refer to the 2006 RAV4 Repair Manual (Pub. No. RM01M1U).
13. Fail-safe
When a malfunction is detected at any of the sensors, there is a possibility of an engine or other malfunction
occurring if the ECM were to continue to control the engine control system in the normal way. To prevent
such a problem, the fail-safe function of the ECM either relies on the data stored in memory to allow the
engine control system to continue operating, or stops the engine if a hazard is anticipated. For details, refer
to the 2006 RAV4 Repair Manual (Pub. No. RM01M1U).