2001 TOYOTA SEQUOIA fuel cap

DI±250
± DIAGNOSTICSENGINE
444 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
RltdDTCP0420Bank 1 catalyst is deterioratedRelated DTCsP0430Bank 2 catalyst is deteriorated
Main sensors/componentsFront and rear heated oxygen sensor
Required sensors/componentsRelated sensors/components
Mass air flow meter, Engine coolant temperature
sensor, Engine speed sensor, Intake air tempera-
ture sensor
Frequency of operationOnce per driving cycle
Duration20 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage11 V±
Intake air temperature±10C (14F)±
Engine coolant temperature75°C (167°F)±
Atmospheric pressure coefficient0.75±
IdleOFF
Engine RPM±3,200 rpm
A/F sensorActivated
Fuel system statusClosed loop
Engine load10 to 70 %
All of the following conditions are metCondition 1, 2 and 3
1. MAF6to 75 g/sec
2. Front catalyst temperature (estimated)620to 830C (1,148 to 1,526F)
3. Rear catalyst temperature (estimated)410 to 830C (770 to 1,526F)
Rear HO2S monitorCompleted
Shift position4th±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Oxygen storage capacity (OSC) of catalystLess than 0.16

A23541
At least 3 minutes
2 seconds
Check
2 seconds
Engine Speed
3,000 rpm
2,000 rpm
Idling
Ignition Switch OFF(a)(b)(c) (d)
Time
Warming up(d)
± DIAGNOSTICSENGINE
DI±251
445 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR RESULT
Refer to page DI±26 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (refer to ºConfirmation Monitorº).
MID (Monitor Identification Data) is assigned to each emissions±related component.
TID (Test Identification Data) is assigned to each test value.
Scaling is used to calculate the test value indicated on generic tools.
Catalyst bank 1 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$21$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
Catalyst bank 2 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$22$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
WAVEFORMS OF AIR±FUEL RATIO (A/F) AND HEATED OXYGEN (HO2) SEN-
SORS
HINT:
Perform the operation with the engine speeds and time durations described below prior to check the wave-
forms of the A/F and HO2 sensors. This is in order to activate the sensors sufficiently to obtain the appropri-
ate inspection results.
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and warm it up with all the accessories switched OFF, until the engine coolant temper-
ature stabilizes.
(c) Run the engine at an engine speed of between 2,500 rpm and 3,000 rpm for at least 3 minutes.
(d) After confirming that the waveform of the heated oxygen sensor (bank 1, 2 sensor 1 (HA1A, HA2A)),
oscillate around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor
(bank 1, 2 sensor 2 (OX1B, OX2B)).

± DIAGNOSTICSENGINE
DI±249
443 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0420 Catalyst System Efficiency Below Threshold
(Bank 1)
DTC P0430 Catalyst System Efficiency Below Threshold
(Bank 2)
MONITOR DESCRIPTION
The ECM uses the two sensors, mounted in front of and behind the Three±way Catalytic Converter (TWC),
to monitor its efficiency.
The first sensor, the Air±Fuel Ratio (A/F) sensor (sensor 1), sends pre±catalyst information to the ECM. The
second sensor, the Heated Oxygen (HO2) sensor (sensor 2), sends post±catalyst information to the ECM.
The ECM compares the information transmitted by these two sensors to determine the efficiency of the TWC
performance and its ability to store oxygen.
When the TWC is functioning properly, the variation in the oxygen concentration in the exhaust gas, after
it has passed through the TWC, is small. In this condition, the voltage output of sensor 2 slowly alternates
between the rich and lean signal voltages (shown in the illustration below). As the TWC performance efficien-
cy deteriorates, its oxygen storage capacity decreases, and the variation in the oxygen concentration in the
exhaust gas increases. As a result, the sensor voltage output fluctuates frequently.
While the catalyst monitor is running, the ECM measures the signal lengths of both sensors 1 and 2, and
calculates the ratio of the signal lengths to determine the extent of the TWC deterioration. If the deterioration
level exceeds the preset threshold, the ECM interprets this as the TWC malfunction. The ECM then illumi-
nates the MIL and sets the DTC.
DTC No.DTC Detecting ConditionTrouble Area
P0420
P0430OSC value smaller than standard value under active air±fuel
ratio control (2 trip detection logic)
Gas leakage on exhaust system
A/F sensor (Bank 1, 2 sensor 1)
Heated oxygen sensor (bank 1, 2 sensor 2)
Three±way catalytic converter
HINT:
Bank 1 refers to the bank that includes cylinder No.1.
Bank 2 refers to the bank that does not include cylinder No.1.
Sensor 1 refers to the sensor mounted in front of the Three±Way Catalytic Converter (TWC) and lo-
cated near the engine assembly.
Sensor 2 refers to the sensor mounted behind the TWC and located far from the engine assembly.
DID87±01

DI±250
± DIAGNOSTICSENGINE
444 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
RltdDTCP0420Bank 1 catalyst is deterioratedRelated DTCsP0430Bank 2 catalyst is deteriorated
Main sensors/componentsFront and rear heated oxygen sensor
Required sensors/componentsRelated sensors/components
Mass air flow meter, Engine coolant temperature
sensor, Engine speed sensor, Intake air tempera-
ture sensor
Frequency of operationOnce per driving cycle
Duration20 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage11 V±
Intake air temperature±10C (14F)±
Engine coolant temperature75°C (167°F)±
Atmospheric pressure coefficient0.75±
IdleOFF
Engine RPM±3,200 rpm
A/F sensorActivated
Fuel system statusClosed loop
Engine load10 to 70 %
All of the following conditions are metCondition 1, 2 and 3
1. MAF6to 75 g/sec
2. Front catalyst temperature (estimated)620to 830C (1,148 to 1,526F)
3. Rear catalyst temperature (estimated)410 to 830C (770 to 1,526F)
Rear HO2S monitorCompleted
Shift position4th±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Oxygen storage capacity (OSC) of catalystLess than 0.16

A23541
At least 3 minutes
2 seconds
Check
2 seconds
Engine Speed
3,000 rpm
2,000 rpm
Idling
Ignition Switch OFF(a)(b)(c) (d)
Time
Warming up(d)
± DIAGNOSTICSENGINE
DI±251
445 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR RESULT
Refer to page DI±26 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (refer to ºConfirmation Monitorº).
MID (Monitor Identification Data) is assigned to each emissions±related component.
TID (Test Identification Data) is assigned to each test value.
Scaling is used to calculate the test value indicated on generic tools.
Catalyst bank 1 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$21$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
Catalyst bank 2 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$22$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
WAVEFORMS OF AIR±FUEL RATIO (A/F) AND HEATED OXYGEN (HO2) SEN-
SORS
HINT:
Perform the operation with the engine speeds and time durations described below prior to check the wave-
forms of the A/F and HO2 sensors. This is in order to activate the sensors sufficiently to obtain the appropri-
ate inspection results.
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and warm it up with all the accessories switched OFF, until the engine coolant temper-
ature stabilizes.
(c) Run the engine at an engine speed of between 2,500 rpm and 3,000 rpm for at least 3 minutes.
(d) After confirming that the waveform of the heated oxygen sensor (bank 1, 2 sensor 1 (HA1A, HA2A)),
oscillate around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor
(bank 1, 2 sensor 2 (OX1B, OX2B)).

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

± 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

A23474
Purge VSV
(Vacuum Switching Valve)
EVAP Hose
(To Throttle Body)
EVAP Hose
(From Canister) Location of EVAP (Evaporative Emission) system:Vent ValveCanister
Pressure Sensor
Vacuum Pump
Purge Line
Fuel Tank
Air Inlet Port Breeding
PipeFuel Tank Cap Refueling ValvePump Module
Air Filter
A23668
EVAP System Circuit:
Intake Manifold
Purge VSV
Cut±Off Valve Roll±Over Valve
CanisterAir Filterfuel tank cap
Service Port
Air Cleaner
Restrictor (0.08 inch)
Refueling Valve Throttle Valve
ECM
Soak Timer
Pump Module
Fuel Tank
± DIAGNOSTICSENGINE
DI±461
655 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
While the engine is running, if a predetermined condition (closed±loop, etc.) is met, the purge VSV is opened
by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the
duty cycle ratio of the purge VSV to control purge flow volume.
The purge flow volume is also determined by the intake manifold pressure.
Atmospheric pressure is allowed
into the canister through the vent valve to ensure that the purge flow is maintained when the negative pres-
sure (vacuum) is applied to the canister.
The following two monitors run to confirm appropriate EVAP system operation.