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Toyota Sequoia (2005). Manual - part 117

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DIAGNOSTICS

ENGINE

DI–263

457

Battery voltage

10 V

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Purge duty cycle

8 %

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TYPICAL MALFUNCTION THRESHOLDS

Detection Criteria

Threshold

Purge VSV stuck open:

FTP when vacuum introduction was compleat

Higher than reference pressure x 0.2

Purge VSV stuck closed:

FTP change for 10 sec. after purge VSV ON

Less than 2.25 mmHg (0.3 kPa)

Purge flow:

Both of the following conditions are met

Condition 1 or 2

1. FTP change when purge operation is started

Less than 0.75 mmHg (0.1 kPa)

2. FTP change during purge operation when vent valve is

closed

Less than 3.75 mmHg (0.5 kPa)

MONITOR RESULT (MODE 06 DATA)

Refer to page

DI–26

for detailed information on Monitor Result.

INSPECTION PROCEDURE

Refer to the EVAP Inspection Procedure (see page

DI–460

DI–264

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DIAGNOSTICS

ENGINE

458

DTC

P0450

Evaporative Emission Control System Pres-
sure Sensor/Switch

DTC

P0451

Evaporative Emission Control System Pres-
sure Sensor/Switch Range/Performance

DTC

P0452

Evaporative Emission Control System Pres-
sure Sensor/Switch Low Input

DTC

P0453

Evaporative Emission Control System Pres-
sure Sensor/Switch High Input

DTC SUMMARY

DTC

Monitoring Items

Malfunction Detection Conditions

Trouble Areas

Detection Tim-

ings

Detection

Logic

P0450

Pressure sensor voltage ab-
normal fluctuation

Sensor output voltage rapidly fluctuates
beyond upper and lower malfunction
thresholds for 0.5 seconds.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

EVAP monitor-
ing (ignition
OFF)

Ignition ON

1 trip

P0451

Pressure sensor noising

Sensor output voltage fluctuates fre-
quently in certain time period.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

EVAP monitor-
ing (ignition
OFF)

Engine running

2 trip

P0451

Pressure sensor stuck

Sensor output voltage does vary in cer-
tain time period.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

EVAP monitor-
ing (ignition
OFF)

2 trip

P0452

Pressure sensor voltage low

Sensor output voltage is less than 0.45
V for 0.5 seconds.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

Ignition ON

EVAP monitor-
ing (ignition
OFF)

1 trip

P0453

Pressure sensor voltage high

Sensor output voltage is more than 4.9
V for 0.5 seconds.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

Ignition ON

EVAP monitor-
ing (ignition
OFF)

1 trip

HINT:
The pressure sensor is built into the pump module.

CIRCUIT DESCRIPTION

The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page

DI–460

DID89–01

B17403

Pressure Sensor Specification:

Output Voltage

Usable Range

4.900 V

4.150 V

1.425 V

0.450 V

Malfunction Area

Pressure

60
kPa

110
kPa

Malfunction Area

Standard atmospheric pressure is 101.3 kPa

HINT:

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DIAGNOSTICS

ENGINE

DI–265

459

MONITOR DESCRIPTION

(a)

DTC P0450: Pressure sensor voltage abnormal fluctua-
tion.
If the pressure sensor voltage output rapidly fluctuates
between less than 0.45 V and more than 4.9 V, the ECM
interprets this as an open or short circuit malfunction in
the pressure sensor or its circuit, and stops the EVAP
(Evaporative Emission) system monitor. The ECM then il-
luminates the MIL and sets the DTC (1 trip detection log-
ic).

(b)

DTC P0451: Pressure sensor noising or stuck
If the pressure sensor voltage output fluctuates rapidly for
10 seconds, the ECM stops the EVAP system monitor.
The ECM interprets this as noise from the pressure sen-
sor, and stops the EVAP system monitor. The ECM then
illuminates the MIL and sets the DTC.
Alternatively, if the sensor voltage output does not
change for 10 seconds, the ECM interprets this as the
sensor being stuck, and stops the monitor. The ECM then
illuminates the MIL and sets the DTC.
(Both the malfunctions are detected by 2 trip detection
logic)

(c)

DTC P0452: Pressure sensor voltage low
If the pressure sensor voltage output is below 0.45 V, the
ECM interprets this as an open or short circuit malfunction
in the pressure sensor or its circuit, and stops the EVAP
system monitor. The ECM then illuminates the MIL and
sets the DTC (1 trip detection logic).

(d)

DTC P0453: Pressure sensor voltage high
If the pressure sensor voltage output is 4.9 V or more, the
ECM interprets this as an open or short circuit malfunction
in the pressure sensor or its circuit, and stops the EVAP
system monitor. The ECM then illuminates the MIL and
sets the DTC (1 trip detection logic).

DI–266

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DIAGNOSTICS

ENGINE

460

MONITOR STRATEGY

P0450