O2 sensor TOYOTA SEQUOIA 2001 Service Repair Manual

B17403
Pressure Sensor Specification:
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:
± DIAGNOSTICSENGINE
DI±265
459 Author: Date:
2005 SEQUOIA (RM1146U)
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
± DIAGNOSTICSENGINE
460 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P0450Evaporative emission control system pressure
sensor/switch chattering
P0451
Evaporative emission control system pressure
sensor noise
Related DTCs
P0451Evaporative emission control system pressure
sensor stuck
P0452Evaporative emission control system pressure
sensor/switch low input
P0453Evaporative emission control system pressure
sensor/switch high input
Required sensors/componentsPump module
Frequency of operationOnce per driving cycle
Duration0.5 sec.: P0450, P0452, P0453
10 sec.: P0451
MIL operationImmediate: P0450, P0452, P0453
2 driving cycles: P0451
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Pressure sensor noise:
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
IAT4.4 to 35°C (40 to 95°F)
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Either of the following conditions is metCondition 1 or 2
1. Time after engine stopped5 hours
2. Engine conditionRunning
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Pressure sensor stuck:
Battery voltage10.5 V±
IAT4.4 to 35°C (40 to 95°F)
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Time after engine stopped5 hours
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.

± DIAGNOSTICSENGINE
DI±267
461 Author: Date:
2005 SEQUOIA (RM1146U) Pressure sensor chattering, low/high voltage:
Battery voltage8 V±
Ignition switchON
StarterOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Pressure sensor noise:
Frequency that FTP change is 0.3 kPa or more10 times or more for 10 sec.
Pressure sensor stuck:
FTP change for 10 sec. during EVAP monitor (0.02 inch
reference pressure)Less than 4.9 mmHg (0.65 kPa)
Pressure sensor chattering:
Pressure sensor voltageLess than 0.45 V, or more than 4.9 V
Pressure sensor low voltage:
Pressure sensor voltageLess than 0.45 V
Pressure sensor high voltage:
Pressure sensor voltageMore than 4.9 V

DI±268
± DIAGNOSTICSENGINE
462 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:

When a vehicle is brought into the workshop, leave it as it is. Do not change the vehicle condi-
tion. For example, do not tighten the fuel tank cap.

Do not disassemble the pump module.

A hand±held tester is required to conduct the following diagnostic troubleshooting procedure.
1 Confirm DTC and EVAP pressure.
PREPARATION:
(a) Connect a hand±held tester to the DLC3.
(b) Turn the ignition switch to ON (do not start the engine).
(c) Turn the tester ON.
CHECK:
(a) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(b) Read DTCs.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / VAPOR
PRESS.
(d) Read the EVAP (Evaporative Emission) pressure displayed on the tester.
RESULT:
Display (DTC Output)Test ResultsSuspected Trouble AreasProceed To
P0451'
Pressure sensorC
P0452Less than 45 kpa (430 mmHg)

Wire harness/connector (ECM ± pressure
sensor)

Pressure sensor

Short in ECM circuit
A
P0453More than 120 kPa (900 mmHg)

Wire harness/connector (ECM ± pressure
sensor)

Pressure sensor

Open in ECM circuit
B
B Go to step 4.
C Go to EVAP inspection procedure
(See page DI±460).
A

B17417
E4
PPMP
± DIAGNOSTICSENGINE
DI±269
463 Author: Date:
2005 SEQUOIA (RM1146U)
2 Measure resistance between terminal PPMP of ECM and body ground.
PREPARATION:
(a) Turn the ignition switch to OFF.
(b) Disconnect the E4 ECM connector.
CHECK:
Measure the resistance between PPMP terminal of the ECM
connector and the body ground.
RESULT:
Test ResultsSuspected Trouble AreasProceed To
10 W or less
Wire harness/connector (ECM ± pressure sensor)

Short in pressure sensor circuitA
10 kW or more
Wire harness/connector (ECM ± pressure sensor)

Short in ECM circuitB
B Go to step 7.
A

B17417
E4
PPMP
A23446
L5
DI±270
± DIAGNOSTICSENGINE
464 Author: Date:
2005 SEQUOIA (RM1146U)
3 Measure resistance between terminal PPMP of ECM and body ground.
PREPARATION:
(a) Disconnect the L5 canister connector.
(b) Disconnect the E4 ECM connector.
CHECK:
Check the resistance between PPMP terminal of the ECM con-
nector and the body ground.
Result:
Test ResultsSuspected Trouble AreasProceed To
10 kW or more
Short in pressure sensor circuitA
10 W or less
Short in wire harness/connector (ECM ± pressure sensor)B
A Go to step 5.
B Go to step 6.

A23508
Wire Harness Side:
Canister Connector
Front View
L5
A23446
L5
± DIAGNOSTICSENGINE
DI±271
465 Author: Date:
2005 SEQUOIA (RM1146U)
4 Measure voltage and resistance of pump module connector.
PREPARATION:
(a) Disconnect the L5 canister connector.
(b) Turn the ignition switch to ON.
CHECK:
Measure the voltage and resistance of the L5 connector.
OK:
Standard:
Tester ConnectionsSpecified Conditions
L5±4 ± Body groundBetween 4.5 V and 5.5 V
L5±3 ± Body groundBetween 4.5 V and 5.5 V
L5±2 ± Body ground100 W or less
RESULT:
Test ResultsSuspected Trouble AreasProceed To
Voltage and resistance within standard ranges
Open in pressure sensor circuitA
Voltage and resistance outside standard ranges
Open in wire harness/connector (ECM ± pressure sensor)B
B Go to step 6.
A
5 Replace charcoal canister assembly.
NEXT Go to step 8.
6 Repair or replace wire harness and connectors.
HINT:
If the exhaust tail pipe has been removed, go to the next step before reinstalling it.
NEXT Go to step 8.

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.

A23486
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
P0455
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
P0456
OK
EVAP Pressure when EVAP system Leaks:
Leak PressureSecond 0.02 inch
Standard x 0.2
± DIAGNOSTICSENGINE
DI±275
469 Author: Date:
2005 SEQUOIA (RM1146U)
(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
RltdDTCP0455Gross leak detectedRelated DTCsP0456Very small leak (0.020 inch hole) detected
Required sensors/componentsPurge VSV, Pump module
Frequency of operationOnce per driving cycles
DurationWithin 15 min. (varies with amount of fuel in tank)
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:±

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)±