O2 sensor TOYOTA SEQUOIA 2001 Service Repair Manual

A23663
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutesON
First 0.02 inch
BCD
OK
Malfunction
ON: Open
OFF: Closed
OFF: VentON: Closed
10
Standard
sec60
E
sec
EVAP Pressure when Vacuum Pump Stuck ON:
± DIAGNOSTICSENGINE
DI±413
607 Author: Date:
2005 SEQUOIA (RM1146U)
(b) P2402: Vacuum pump stuck ON
In operation B, the vacuum pump creates negative pressure (a vacuum) through the 0.02 inch orifice. The
EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the pressure sensor,
to determine the 0.02 inch leak pressure standard. If the pressure is higher than ±1.06 kPa (±7.95 mmHg)*,
or lower than ±4.85 kPa (±36.38 mmHg)*, the ECM interprets this as the vacuum pump being stuck ON (re-
maining ON all the time). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The thresholds vary according to the atmospheric pressure measured in operation A. The values de-
scribed above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
HINT:
The detection logic of DTCs P2401 and P2402 is the same because in both cases the 0.02 inch leak pressure
standard measured in operation B is compared to the atmospheric pressure registered in operation A. The
ECM calculates the difference between these pressures by deducting [the 0.02 inch leak pressure standard]
from [the stored atmospheric pressure], and uses this to monitor the EVAP system pressure change.
MONITOR STRATEGY
RltdDTCP2401Vacuum pump stuck OFFRelated DTCsP2402Vacuum pump stuck ON
Required sensors/componentsPump module
Frequency of operationOnce per driving cycles
DurationWithin 2 min.
MIL operation2 driving cycles
Sequence of operationNone

DI±414
± DIAGNOSTICSENGINE
608 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee 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:±
Atmospheric pressure525 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)±

A23480
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)
± DIAGNOSTICSENGINE
DI±417
611 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.

A23665
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutes
sec ON
First 0.02 inch
BCD
EVAP Pressure when Vent Valve Stuck ON (closed):
OK Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
sec4
DI±418
± DIAGNOSTICSENGINE
612 Author: Date:
2005 SEQUOIA (RM1146U)
(a) P2419: Vent valve stuck closed
In operation B, the vacuum pump creates negative pressure (a vacuum) through the 0.02 inch orifice. The
EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the pressure sensor,
to determine the 0.02 inch leak pressure standard. If the pressure exceeds ±1.06 kPa (±7.95 mmHg)* 4 se-
conds after the vacuum pump is turned ON, the ECM interprets this as the vent valve being stuck closed.
The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The threshold varies according to the atmospheric pressure measured in operation A. The value described
above is based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.

A23666
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutesON
First 0.02 inch
BCD
EVAP Pressure when Vent Valve Stuck OFF (vent):
OK
Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
± DIAGNOSTICSENGINE
DI±419
613 Author: Date:
2005 SEQUOIA (RM1146U)
(b) P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closes) and the EVAP (Evaporative Emission) system pressure is
then measured by the ECM, using the 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.
MONITOR STRATEGY
RltdDTCP2419Vent valve stuck openRelated DTCsP2420Vent valve stuck closed
Required sensors/componentsVent valve
Frequency of operationOnce per driving cycle
Duration8 sec. (P2419), 10 sec. (P2420)
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee 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:±
Atmospheric pressure525 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

DI±420
± DIAGNOSTICSENGINE
614 Author: Date:
2005 SEQUOIA (RM1146U) 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)±
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)

A20311
Pressure
SensorECM
VC
AIP
E2 VC
PIM
E2 DI±422
± DIAGNOSTICSENGINE
616 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2430 Secondary Air Injection System Air Flow/
Pressure Sensor Circuit Bank 1
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
CIRCUIT DESCRIPTION
Refer to DTC P412 on page DI±234.
DTC No.DTC Detecting ConditionTrouble Area
P2430
While the engine is running, voltage output of the pressure
sensor indicates 0.1V or less, or indicates 4.8V or more.
(1 trip detection logic)
P2431
The pressure sensor indicates less than 45 kPa (338 mHg), or
more than 135 kPa (1013 mHg).
(1 trip detection logic)

Pressure sensor
Ohti iit
P2432
While the engine is running, voltage output of pressure sensor
remains below 0.1 V.
(1 trip detection logic)
Open or short in pressure sensor circuit

ECM
P2433
While the engine is running, voltage output of the pressure
sensor remains above 4.8 V.
(1 trip detection logic)
MONITOR DESCRIPTION
The ECM observes the pressure in the secondary air passage
using the pressure sensor located on the air switching valve in
the secondary air injection system.
If there is a defect in the sensor or the sensor circuit, the voltage
level will deviate from the normal operating range, the ECM in-
terprets this deviation as a defect in the pressure sensor circuit
and sets a DTC.
DIDMT±01

± DIAGNOSTICSENGINE
DI±423
617 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P2430Air flow/pressure sensor circuit range check
(Fluctuating)
P2431Air flow/pressure sensor circuit rationality
Related DTCsP2432Air flow/Pressure sensor circuit range check
(Low voltage)
P2433Air flow/pressure sensor circuit range check
(High voltage)
Required sensors/componentsPressure sensor
Frequency of operationContinuous
DurationP2430, P2432, P2433: 0.5 sec.
P2431: 5 sec.
MIL operationP2430, P2432, P2433: Immediate
P2431: 2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
StarterOFF
Time after starter turned from ON to OFF2 sec.±
Battery voltage8 V±
Ignition switchON
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P2430:
Air pressure sensor voltageLess than 0.1 V, or more than 4.8 V
P2432:
Air pressure sensor voltageLess than 0.1 V
P2433:
Air pressure sensor voltageMore than 4.8 V
P2431:
Air pressureLess than 338 mmHg (45 kPa), or more than 1013 mmHg (135 kPa)

A23557
ECM A42
Air Pressure Sensor
VC
AIP
E2
E8 E8 E8
2832 23
VC
AIP
E2EB4
EB4
EB4G±B G±B
B±Y
B±Y
G±W
G±W6 5 15 V
B17412
E8
E2AIP VC
B17439
Wire Harness Side:
Pressure Sensor Connector
A42
E2
AIP VC
DI±424
± DIAGNOSTICSENGINE
618 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check for open and short in harness and connector between pressure sensor
and ECM (See page IN±35).
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A42 pressure sensor connector.
(c) Disconnect the E8 ECM connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VC (A42±1) ± VC (E8±23)
AIP (A42±2) ± AIP (E8±32)
E2 (A42±3) ± AIP (E8±28)
Below 1 W
VC (A42±1) or VC (E8±23) ±
Body ground
AIP (A42±2) or AIP (E8±32) ±
Body ground
10 kW or higher
NG Repair or replace harness and connector.
OK

B17434
Pressure Gauge
Pressure Sensor
± DIAGNOSTICSENGINE
DI±425
619 Author: Date:
2005 SEQUOIA (RM1146U)
2 Inspect pressure sensor.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Connect the pressure gauge to the pressure sensor as
shown in the illustration.
(c) Connect the hand±held tester to the DLC3 on the vehicle.
(d) Turn the ignition switch ON and push the hand±held tes-
ter main switch ON (Do not start engine).
(e) Select the following items: DIAGNOSIS / ENHANCED
OBD II / DATA LIST / 2ND AIR PRESS.
CHECK:
Check that the pressure displayed on the hand±held tester fluc-
tuates when applying the pressure to the pressure sensor with
the pressure gauge.
OK:
Pressure fluctuates in response to the pressure ap-
plied with pressure gauge.
NG Replace pressure sensor (See page EC±22).
OK
Replace ECM (See page SF±80).