2001 TOYOTA SEQUOIA check engine

± DIAGNOSTICSENGINE
DI±273
467 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0455 Evaporative Emission Control System Leak
Detected (Gross Leak)
DTC P0456 Evaporative Emission Control System Leak
Detected (Very Small Leak)
DTC SUMMARY
DTCMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P0455EVAP gross leak
Vacuum pump creates negative pressure
(vacuum) in EVAP system and EVAP sys-
tem pressure measured. 0.02 inch leak
pressure standard is measured at the start
and at the end of the leak check.
If stabilized pressure higher than [second
0.02 inch leak pressure standard x 0.2],
ECM determines that EVAP system has
large leakage.
Fuel tank cap (loose)

Leakage from EVAP line
(Canister ± Fuel tank)

Leakage from EVAP line
(Purge VSV ± Canister)

Pump module

Leakage from fuel tank

Leakage from canister
While
ignition
switch
OFF
2 trip
P0456EVAP small leak
Vacuum pump creates negative pressure
(vacuum) in EVAP system and EVAP sys-
tem pressure measured. 0.02 inch leak
pressure standard is measured at the start
and at the end of the leak check.
If stabilized pressure larger than second
0.02 inch leak pressure, ECM determines
that EVAP system has small leakage.
Same above
While
ignition
switch
OFF
2 trip
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page
DI±460).
DID8A±01

B17399
Fuel Tank Canister
Vacuum Pump: OFF Pressure Sensor 0.02 Inch Orifice
Pump Module
Operation A: Atmospheric Pressure Measurement
Vent Valve: OFF (vent)
Operation D: Purge VSV monitor Operation B: 0.02 Inch Leak Pressure Measurement
Negative
Pressure Atmospheric
Pressure
Operation C: EVAP Leak Check
Air Filter
Purge VSV: OFFOFF (vent)
ON
OFF
OFF
ON
ON (closed)ON
ON
ON (closed)
DI±274
± DIAGNOSTICSENGINE
468 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
5 hours* after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacu-
um) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions
based on the EVAP pressure.
HINT:
*: If the engine coolant temperature is not below 35C (95F) 5 hours after the ignition switch is turned off,
the monitor check starts 2 hours later. If it is still not below 35C (95F) 7 hours after the ignition switch is
turned off, the monitor check starts 2.5 hours later.
SequenceOperationsDescriptionsDuration
±ECM activationActivated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned to OFF.±
AAtmospheric pressure
measurement
Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to
register atmospheric pressure.
If EVAP pressure is not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM
cancels EVAP system monitor.
10 seconds
B
First 0.02 inch leak
pressure measure-
mentIn order to determine 0.02 inch leak pressure standard, vacuum pump creates negative pres-
sure (vacuum) through 0.02 inch orifice and them ECM checks if vacuum pump and vent
valve operate normally.
60 seconds
CEVAP system pres-
sure 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 the measured value as it will be used in the leak check.
If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor.
15 minutes*
DPurge VSV monitorPurge VSV opened and then EVAP system pressure measured by ECM.
Large increase indicates normal.10 seconds
E
Second 0.02 inch leak
pressure measure-
mentLeak check is performed after second 0.02 inch leak pressure standard is measured.
If stabilized system pressure higher than second 0.02 inch leak pressure standard, ECM
determines that EVAP system leaking.
60 seconds
FFinal checkAtmospheric pressure measured and then monitoring result recorded by ECM.±
* If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

DI±276
± DIAGNOSTICSENGINE
470 Author: Date:
2005 SEQUOIA (RM1146U) Atmospheric pressure
525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
Vehicle speed±4 km/h (2.5 mph)
Ignition switchOFF
Engine conditionNot running
Time after engine stopped5 hours
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met
before IG switch OFFCondition 1 and 2
1. Duration that vehicle is driven5 min.±
2. Purge flowExecuted
ECT4.4 to 35°C (40 to 95°F)
IAT4.4 to 35°C (40 to 95°F)
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Key±off monitor sequence1 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 setCondition 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 pressureSaturated
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 setCondition 1 and 2
1. Vacuum introduction time±15 min.
2. FTPFTP 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)±

± DIAGNOSTICSENGINE
DI±277
471 Author: Date:
2005 SEQUOIA (RM1146U) 6. Second reference pressure measure-
ment
±
Next sequence is run if all of following
conditions setCondition 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 pressureSaturated
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 CriteriaThreshold
Small leak (0.020 inch) malfunction detection:
FTP when vacuum introduction was compleatBetween 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 compleatHigher 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).

DI±280
± DIAGNOSTICSENGINE
474 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when
a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was
running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, as well as other
data from the time when a malfunction occurred.
1 Check operation of speedometer.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and push the hand±held tester main switch ON.
(c) Start the engine.
(d) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / PRIMARY / VEHICLE SPD.
CHECK:
Read the mass air flow rate on the hand±held tester.
RESULT:
Vehicle speedProceed to
Vehicle speed remains 0 km/h (0 mph)A
Vehicle speed is lower than actual speedA
Vehicle speed is same as actual speedB
B Check for intermittent problems
(See page DI±11).
A

B17411
SPD(+) E6
E5
E1
AT7809
4 to 6 V
Turn the Wheel
3
2
1
I25536
Component Side Connector:
Vehicle Speed Sensor
± DIAGNOSTICSENGINE
DI±281
475 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check voltage between terminal SPD and E1 of ECM connector.
PREPARATION:
(a) Shift the shift lever to neutral.
(b) Jack up the rear wheel on one side.
(c) Turn the ignition switch ON.
CHECK:
Measure the voltage between the specified terminal of the E5
and E6 ECM connector when the wheel is turned slowly.
OK:
Standard:
Tester ConnectionSpecified Condition
SPD (E5±8) ± E1 (E6±1)Generated intermittently
HINT:
The output voltage should fluctuate up and down similarly to the
diagram on the left when the wheel is turned slowly.
OK Replace ECM (See page SF±80).
NG
3 Check vehicle speed sensor.
PREPARATION:
(a) Disconnect the vehicle speed sensor connector.
(b) Connect the battery positive (+) lead to terminal 1 and the
battery negative (±) lead to terminal 2.
(c) Connect the tester positive (+) lead to terminal 3 and the
tester negative (±) lead to terminal 2.
(d) Shift the shift lever to N position.
(e) Rotate the shaft.
CHECK:
Check that there is voltage change between terminals 2 and 3.
OK:
Standard: 0 V to 10 V or more
NG Replace vehicle speed sensor.
OK

BR3795OK NGClearance
B17411
SPD(+) E5
A23540
Wire Harness Side:
Front View
Combination Meter Connector C5
DI±282
± DIAGNOSTICSENGINE
476 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check sensor installation (Vehicle speed sensor).
CHECK:
Check the vehicle speed sensor installation.
OK:
The vehicle speed sensor is installed properly.
NG Tighten sensor installation bolt.
OK
5 Check for open and short in harness and connector between combination meter
and ECM.
PREPARATION:
(a) Disconnect the C5 combination meter connector.
(b) Disconnect the E5 ECM connector.
CHECK:
Check for resistance between the wire harness side connec-
tors.
OK:
Standard (Check for open):
Symbols (Terminal No.)Specified condition
SPD (E5±8) ± C5±25Below 1 W
Standard (Check for short):
Symbols (Terminal No.)Specified condition
SPD (E5±8) or C5±25 ± Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Check combination meter circuit (See page
DI±1632

± DIAGNOSTICSENGINE
DI±283
477 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0504 Brake Switch ºAº/ºBº Correlation
CIRCUIT DESCRIPTION
In addition to turning on the stop lamps, the stop lamp switch signals are used for a variety of engine, trans-
mission, and suspension functions as well as being an input for diagnostic checks. It is important that the
switch operates properly, therefore this switch is designed with two complementary signal outputs: STP and
ST1±. The ECM analyzes these signal outputs to detect malfunctions in the stop lamp switch.
HINT:
Normal condition is as shown in the table.
SignalBrake pedal releasedIn transitionBrake pedal depressed
STPOFFONON
ST1±ONONOFF
DTC No.DTC Detection ConditionTrouble Area
P0504
Conditions (a), (b) and (c) continue for 0.5 sec. or more:
(a) Ignition switch ON
(b) Brake pedal released
(c) STP signal is OFF when the ST1± signal is OFF
Short in stop lamp switch signal circuit

Stop lamp fuse

Stop lamp switch

ECM
DID8C±01