Toyota Sequoia (2005). Manual - part 120

A23486

Purge VSV

Vent Valve

Vacuum Pump

EVAP Pressure

Positive

Leak Pressure

sec

Negative

ON

ON

Sequence

Time

A

10

sec

60

Within 15 minutes

sec

ON

First 0.02 inch

B

C

D

P0455

ON: Open

OFF: Closed

OFF: Vent

ON: Closed

10

Standard

sec

60

E

P0456

OK

EVAP Pressure when EVAP system Leaks:

Leak Pressure

Second 0.02 inch

Standard x 0.2

–

DIAGNOSTICS

ENGINE

DI–275

469

(a)

P0455: EVAP (Evaporative Emission) gross leak

In operation C, the vacuum 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 0.02 inch leak pres-
sure standard 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 vacuum 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 0.02 inch leak pres-
sure standard, the ECM determines that the EVAP system has a small leakage, illuminates the MIL and sets
the DTC (2 trip detection logic).

MONITOR STRATEGY

R l t d DTC

P0455

Gross leak detected

Related DTCs

P0456

Very small leak (0.020 inch hole) detected

Required sensors/components

Purge VSV, Pump module

Frequency of operation

Once per driving cycles

Duration

Within 15 min. (varies with amount of fuel in tank)

MIL operation

2 driving cycles

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

It

Specification

Item

Minimum

Maximum

The monitor will run whenever these

DTCs are not present

See page 

DI–18

Following values are when atmospheric is

760 mmHg (100 kPa)

–

EVAP key–off monitor runs when all of the

following conditions met:

–

DI–276

–

DIAGNOSTICS

ENGINE

470

Atmospheric pressure

525 to 825 mmHg (70 to 110 kPa)

Battery voltage

10.5 V

–

Vehicle speed

–

4 km/h (2.5 mph)

Ignition switch

OFF

Engine condition

Not running

Time after engine stopped

5 hours

FTP sensor malfunction (P0450, P0452,

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 the following conditions are met

before IG switch OFF

Condition 1 and 2

1. Duration that vehicle is driven

5 min.

–

2. Purge flow

Executed

ECT

4.4 to 35

°

C (40 to 95

°

F)

IAT

4.4 to 35

°

C (40 to 95

°

F)

Example of re–start time

–

First time

7 hours

Second time

9 hours and 30 min.

Key–off monitor sequence

1 to 8

1. Atmospheric pressure

–

Next sequence is run if following condition

set

–

Atmospheric pressure change for 10 sec.

–

2.25 mmHg (0.3 kPa) for 1 sec.

2. First reference pressure

–

Next sequence is run if all of following

conditions set

Condition 1, 2 and 3

1. FTP when 4 sec. after reference pres-

sure measurement

–

–7.5 mmHg (–1 kPa)

2. Reference pressure

–36.38 to –7.93 mmHg (–4.85 to –1.057 kPa)

3. Reference pressure

Saturated

3. Vent valve stuck closed check

–

Next sequence is run if following condition

set

–

FTP change for 10 sec. after vent valve

ON (closed)

2.25 mmHg (0.3 kPa)

–

4. Vacuum introduction and leak

–

Next sequence is run if both of following

conditions set

Condition 1 and 2

1. Vacuum introduction time

–

15 min.

2. FTP

FTP was saturated

5. Purge VSV stuck closed check

–

Next sequence is run if following condition

set

–

FTP change for 10 sec. after purge VSV

ON (open)

2.25 mmHg (0.3 kPa)

–

–

DIAGNOSTICS

ENGINE

DI–277

471

6. Second reference pressure measure-

ment

–

Next sequence is run if all of following

conditions set

Condition 1, 2, 3 and 4

1. FTP when 4 sec. after reference pres-

sure measurement

–

–7.5 mmHg (–1 kPa)

2. Reference pressure

–36.38 to –7.93 mmHg (–4.85 to –1.057 kPa)

3. Reference pressure

Saturated

4. Reference pressure difference between

first and second

–

5.25 mmHg (0.7 kPa)

7. Leak check

–

Next sequence is run if following condition

set

–

FTP when vacuum introduction was com-

plete

–

Second reference pressure

8. Atmospheric pressure

–

Monitor is complete if following

–

Atmospheric pressure difference between

sequence 1 and 8

–

2.25 mmHg (0.3 kPa)

TYPICAL MALFUNCTION THRESHOLDS

Detection Criteria

Threshold

Small leak (0.020 inch) malfunction detection:

FTP when vacuum introduction was compleat

Between 1 and 2

Condition 1.

Higher than second reference pressure

Condition 2.

Lower than reference pressure x 0.2

Gross leak detection:

FTP when vacuum introduction was compleat

Higher than reference pressure x 0.2

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

).

P22487

Vehicle Speed
Sensor

Combination

Meter

ECM

4–pulse

4–pulse

DI–278

–

DIAGNOSTICS

ENGINE

472

DTC

P0500

Vehicle Speed Sensor ”A”

DTC

P0503

Vehicle Speed Sensor ”A” Intermittent/
Erratic/High

CIRCUIT DESCRIPTION

The No.1 vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is ro-
tated by the transmission output shaft via the driven gear. After this signal is converted into a more precise
rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted
to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.

DTC No.

Proceed to

DTC Detection Condition

Trouble Area

P0500

Step 1

No vehicle speed sensor sig-

nal to ECM under following

conditions: (2 trip detection

logic)

Vehicle is being driven

Combination meter

Open or short in vehicle speed sensor circuit

Vehicle speed sensor

ECM

P0503

DI–11

Intermittent problem in the ve-

hicle speed sensor circuit

ECM

MONITOR DESCRIPTION

The ECM assumes that the vehicle is driven when the park/neutral position switch is OFF and it has been
over 4 sec. since the actual vehicle speed was 9 km/h (6 mph) or more.
If there is no signal from the vehicle speed sensor when these conditions are satisfied, the ECM concludes
that there is a fault in the vehicle speed sensor. The ECM will turn on the MIL and a DTC is set.

DID8B–01