2001 TOYOTA SEQUOIA O2 sensor

± DIAGNOSTICSENGINE
DI±463
657 Author: Date:
2005 SEQUOIA (RM1146U)Components
Operations
CanisterContains activated charcoal to absorb EVAP (Evaporative Emissions) generated in fuel tank.
Cut±off valveLocated in fuel tank. Valve floats and closes when fuel tank is 100 % full.
Purge VSV (Vacuum
Switching Valve)Opens or closes line between canister and intake manifold. ECM uses purge VSV to control EVAP purge flow. In order
to discharge EVAP absorbed by canister to intake manifold, ECM opens purge VSV. EVAP discharge volume to intake
manifold controlled by purge VSV duty cycle ratio (current±carrying time). (Open: ON, Close: OFF)
Refueling valve
Controls EVAP pressure from fuel tank to canister. Valve consists of diaphragm, spring and restrictor (diameter: 0.08
inch). When fuel vapor and pressure inside fuel tank increase, valve opens. While EVAP purged, valve closes and re-
strictor prevents large amount of vacuum from affecting pressure in fuel tank. Valve opened while refueling. When valve
open, adding fuel into fuel tank possible.
Roll±over valveLocated in fuel tank. Valve closes by its own weight when vehicle overturns to prevent fuel from spilling out.
Service portUsed for connecting vacuum gauge for inspecting EVAP system.
Soak timerBuilt into ECM. To ensure accurate EVAP monitor, measures 5 hours* after ignition switch turned to OFF. This allows
fuel to cool down, stabilizing Fuel Tank Pressure (FTP). When approx. 5 hours
* elapsed, ECM activates.
Pump moduleConsists of (a) to (d) below. Pump module cannot be disassembled.
(a) Vent valve
Vents and closes EVAP system. When ECM turns valve ON, EVAP system closed. When, ECM turns valve OFF, EVAP
system vented. Negative pressure (vacuum) created in EVAP system to check for EVAP leaks by closing purge VSV,
turning on vent valve (closed) and operating vacuum pump (refer to fig. 1).
(b) Pressure sensorIndicates pressure as voltages. ECM supplies regulated 5 V to pressure sensor, and uses feedback from sensor to
monitor EVAP system pressure (refer to fig 2).
(c) Vacuum pumpCreates negative pressure (vacuum) in EVAP system for leak check.
(d) 0.02 inch orificeHas opening with 0.02 inch diameter. Vacuum produced through orifice by closing purge VSV, turning off vent valve and
operating vacuum pump, to monitor 0.02 inch leak pressure. 0.02 inch leak pressure indicates small leak of EVAP.
HINT:
*:If the engine coolant temperature is not below 35C after 5 hours after the ignition switch is turned off, the
monitor check starts 2 hours later. If it is still not below 35C 7 hours after the ignition switch is turned off,
the monitor check starts 2.5 hours later.

A23494
Pump Module (fig. 1):
Condition: Purge FlowCondition: Leak Check
From Refueling Valve
To Air Filter
(Atmosphere)
Vacuum Pump: OFFVent Valve: OFF
(vent)
Pressure Sensor 0.02 Inch Orifice
Canister
: Airflow
Vacuum Pump: ON
Vent Valve: ON
(closed)
A23495
Pressure Sensor Specification (fig. 2)
Output Voltage
Usable Range
4.900 V
4.150 V
1.425 V
0.450 V
Malfunction Area
Pressure
60
kPa11 0
kPa
Malfunction Area
Standard atmospheric pressure is 101.3 kPaHINT:
A23496
Soak Timer Circuit (fig. 3)
Ignition Switch
IGSW
Power
ECM
EFI MAIN
MREL+B
15 ASource IC
Soak Timer IC Main Relay
Control IC
Battery DI±464
± DIAGNOSTICSENGINE
658 Author: Date:
2005 SEQUOIA (RM1146U)

A23565
L5
Pump Module
Pressure Sensor
Vacuum Pump
Vent Valve
Engine Room R/B
BatteryJ/C
V4
Purge
VSVVC
PPMP
E2
MPMP
VPMP
PRG
MREL
EFI Relay
F10
FL Block
54
BBEFI No.1
2D1
53EFI No.2
2A 2 4
1
8
9 3
2
G±R AA J/C J2
G±RG±R
G±R G±R
IA44J/C J16
BBBJ/C
IG422
G±RW±G
E8 34
B±W
E68
B±WIA4
14
2H6
21 2F1
W±B
J/C J5 AJ48
J49 FLG±R BB12
G±R
G±R
BN15 P±L
BN1BN1 BN1 BN1 BN1
P±L 6
BB18
P±L P±L
J49
J48 B
H
E456
V±G
J48K
J49E
V±G
BB17
V±G V±G4 G±W3
G±W
BB24
G±W
IJ33
G±W
IG46
G±W
E8 2822
E4 E4 R±G
IJ34
R±G
BB22
R±G 2
R±GG±B1
G±B
BB23
G±B
IJ314
G±B
IG47
G±B
E823
BN1 8 W±B
W±B
BI
EDECM
± DIAGNOSTICSENGINE
DI±465
659 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

0.02 inch orifice clogged
Pressure sensor voltage lowP043E
P043FP0441 P0451 P0452 P0453 P0455 P0456 P2419P2401
P2402
0.02 inch orifice high±flow
Pressure sensor stuck
Pressure sensor noising
Gross leak
Small leak
Vacuum pump stuck OFF
Vacuum pump stuck ON
Vent valve stuck ON (closed)
Vent valve stuck OFF (vent) Purge VSV stuck open
Purge VSV stuck closed
Pressure sensor voltage high
DTCs
Malfunctioning AreasP2420P0450
DI±466
± DIAGNOSTICSENGINE
660 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:
A hand±held tester is required to conduct the following diagnostic troubleshooting procedure.
HINT:

Using hand±held tester monitor results enables the EVAP (Evaporative Emission) system to be con-
firmed.

Read freeze frame data using a hand±held tester Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.
1 Confirm DTC.
(a) Turn the ignition switch to OFF and wait for 10 seconds.
(b) Turn the ignition switch to ON.
(c) Turn the ignition switch to OFF and wait for 10 seconds.
(d) Connect a hand±held tester to the DLC3.
(e) Turn the ignition switch to ON and turn the tester ON.
(f) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(g) Confirm DTCs and freeze frame data.
If any EVAP system DTCs are set, the malfunctioning area can be determined using the table below.
NOTICE:
If the 0.02 inch reference pressure difference between the first and second checks is greater than
the specification, the DTCs corresponding to the reference pressure (P043E, P043F, P0441, P0455,
P0456, P2401, P2420) will be all stored.
NEXT

A23499
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
ON: Open
NegativeONON
Steps
(Reference)
ON
OFF: Closed
OFF: Vent ON: Closed
10
sec
1/5
Time
Pressure Sensor Noising
OK
Leak Pressure First 0.02 inch
Standard
± DIAGNOSTICSENGINE
DI±469
663 Author: Date:
2005 SEQUOIA (RM1146U)
4 Perform EVAP system step 1/5 check.
(a) Check the EVAP pressure in step 1/5.
Result:
DTCs*Test ResultsSuspected Trouble AreasProceed To
'Virtually no variation in EVAP pressureNot yet determinedA
P0451EVAP pressure fluctuates by
0.3 kPa
(2.25 mmHg) or morePressure sensor noisingB
*: The DTCs relating to the EVAP system displayed on a hand±held tester when checking.
B Go to step 30
A

A23502
ON
Within 15 minutes
2/5
Vent Valve Stuck open (vent)
3/5
ONON
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Negative
Steps
(Reference)TimeON: Open
OFF: Closed
OFF: Vent ON: Closed
Leak Pressure First 0.02 inch
Standard
DI±472
± DIAGNOSTICSENGINE
666 Author: Date:
2005 SEQUOIA (RM1146U)
7 Perform EVAP system step 2/5 to 3/5 check.
(a) Check the EVAP pressure increase in step 3/5.
Result:
DTCs*Test ResultsSuspected Trouble AreasProceed To
'
EVAP pressure increases by 0.3 kPa (2.25 mmHg)
or more within 10 seconds of proceeding from step
2/5 to step 3/5
Not yet determinedA
P2420No variation in EVAP pressure despite proceeding
from step 2/5 to step 3/5Vent valve stuck open (vent)B
P0451No variation in EVAP pressure during steps 1/5
through 3/5Pressure sensor malfunction stuckC
*: The DTCs relating to the EVAP system displayed on a hand±held tester when checking.
B Go to step 19.
C Go to step 30.
A

DIDII±01
DI±516
± DIAGNOSTICSAUTOMATIC TRANSMISSION
710 Author: Date:
2005 SEQUOIA (RM1146U)
DEFINITION OF TERMS
TermDefinition
Monitor descriptionDescription of what the ECM monitors and how it detects malfunctions (monitoring purpose and its details).
Related DTCsA group of diagnostic trouble codes that are output by the ECM based on the same malfunction detection logic.
Typical enabling condition
Preconditions that allow the ECM to detect malfunctions.
With all preconditions satisfied, the ECM sets the DTC when the monitored value(s) exceeds the malfunction
threshold(s).
Sequence of operation
The priority order that is applied to monitoring, if multiple sensors and components are used to detect the malfunc-
tion.
While another sensor is being monitored, the next sensor or component will not be monitored until the previous
monitoring has concluded.
Required sensor/compo-
nentsThe sensors and components that are used by the ECM to detect malfunctions.
Frequency of operation
The number of times that the ECM checks for malfunctions per driving cycle.
ºOnce per driving cycleº means that the ECM detects malfunction only one time during a single driving cycle.
ºContinuousº means that the ECM detects malfunction every time when enabling condition is met.
DurationThe minimum time that the ECM must sense a continuous deviation in the monitored value(s) before setting a
DTC. This timing begins after the ºtypical enabling conditionsº are met.
Malfunction thresholdsBeyond this value, the ECM will conclude that there is a malfunction and set a DTC.
MIL operation
MIL illumination timing after a defect is detected.
ºImmediatelyº means that the ECM illuminates MIL the instant the ECM determines that there is a malfunction.
º2 driving cycleº means that the ECM illuminates MIL if the same malfunction is detected again in the 2nd driving
cycle.
Component operating range
Normal operation range of sensors and solenoids under normal driving conditions.
Use these ranges as a reference.
They cannot be used to judge if a sensor or solenoid is defective or not.

DIDIJ±01
± DIAGNOSTICSAUTOMATIC TRANSMISSION
DI±517
711 Author: Date:
2005 SEQUOIA (RM1146U)
TOYOTA PART AND SYSTEM NAME LIST
This reference list indicates the part names used in this manual along with their definitions.
Part and system nameDefinition
Toyota HCAC system, Hydrocarbon adsorptive Catalyst
(HCAC) system, HC adsorptive three±way catalystHC adsorptive three±way catalytic converter
Variable Valve Timing sensor, VVT sensorCamshaft position sensor
Variable valve timing system, VVT systemCamshaft timing control system
Camshaft timing oil control valve, Oil control valve OCV,
VVT, VSVCamshaft timing oil control valve
Variable timing and lift, VVTLCamshaft timing and lift control
Crankshaft position sensor ºAºCrankshaft position sensor
Engine speed sensorCrankshaft position sensor
THAIntake air temperature
Knock control moduleEngine knock control module
Knock sensorEngine knock sensor
Mass or volume air flow circuitMass air flow sensor circuit
Vacuum sensorManifold air pressure sensor
Internal control module, Control module, Engine control
ECU, PCMPower train control module
FC idleDeceleration fuel cut
Idle air control valveIdle speed control
VSV for CCV, Canister close valve VSV for canister controlEvaporative emissions canister vent valve
VSV for EVAP, Vacuum switching valve assembly No. 1,
EVAP VAV, Purge VSVEvaporative emissions canister purge valve
VSV for pressure switching valve, Bypass VSVEvaporative emission pressure switching valve
Vapor pressure sensor, EVAP pressure sensor, Evaporative
emission control system pressure sensorFuel tank pressure sensor
Charcoal canisterEvaporative emissions canister
ORVR systemOn±board refueling vapor recovery system
Intake manifold runner controlIntake manifold tuning system
Intake manifold runner valve, IMRV, IACV (runner valve)Intake manifold tuning valve
Intake control VSVIntake manifold tuning solenoid valve
AFSAir fuel ratio sensor
O2 sensorHeater oxygen sensor
Oxygen sensor pumping current circuitOxygen sensor output signal
Oxygen sensor reference ground circuitOxygen sensor signal ground
Accel position sensorAccelerator pedal position sensor
Throttle actuator control motor, Actuator control motor, Elec-
tronic throttle motor, Throttle control motorElectronic throttle actuator
Electronic throttle control system, Throttle actuator control
systemElectronic throttle control system
Throttle/pedal position sensor, Throttle/pedal position switch,
Throttle position sensor/switchThrottle position sensor
Turbo press sensorTurbocharger pressure sensor
Turbo VSVTurbocharger pressure control solenoid valve
P/S pressure switchPower±steering pressure switch
VSV for ACMActive control engine mount
Speed sensor, Vehicle speed sensor ºAº, Speed sensor for
skid control ECUVehicle speed sensor
ATF temperature sensor, Trans. fluid temp. sensor, ATF
temperature sensor ºAºTransmission fluid temperature sensor
Electronic controlled automatic transmission, ECTElectronically controlled automatic
Intermediate shaft speed sensor ºAºCounter gear speed sensor