2001 TOYOTA SEQUOIA engine

DI±444
± DIAGNOSTICSENGINE
638 Author: Date:
2005 SEQUOIA (RM1146U)
DTC U0001 High Speed Can Communication Circuit
CIRCUIT DESCRIPTION
The engine control unit and the transmission control unit are located inside the ECM. The engine control unit
intercommunicates with the transmission control ECU with the Controller Area Network (CAN).
If there is a problem in this intercommunication, the ECM sets a DTC.
DTC No.DTC Detection ConditionTrouble Area
U0001
The following conditions are met for 2 seconds (1 trip detection
logic):
(a) Ignition switch ON
(b) Battery voltage is 10 V or more
(c) No intercommunication between engine control ECU and
transmission control ECU
ECM
INSPECTION PROCEDURE
Replace ECM (See page SF±80)
DID8J±01

± DIAGNOSTICSENGINE
DI±445
639 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P043E Evaporate Emission System Reference Ori-
fice Clog Up
DTC P043F Evaporate Emission System Reference Ori-
fice High Flow
DTC SUMMARY
DTCsMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P043E0.02 inch orifice clogged
Vacuum pump creates negative pressure
through 0.02 inch orifice, and EVAP system
pressure is measured to determine leak
pressure standard. 0.02 inch leak pressure
standard is measured at the start and at the
end of the leak check.
If system pressure lower than ±4.85 kPa
(±36.38 mmHg)*, ECM determines that
0.02 inch orifice has clogging malfunction.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM

Leakage from EVAP sys-
tem
While
ignition
switch is
OFF
2 trip
P043F0.02 inch orifice high±flow
Vacuum pump creates negative pressure
through 0.02 inch orifice, and EVAP system
pressure is measured to determine leak
pressure standard. 0.02 inch leak pressure
standard is measured at the start and at the
end of the leak check.
If system pressure higher than ±1.06 kPa
(±7.95 mmHg)*, ECM determines that 0.02
inch orifice has high±flow malfunction.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM

Leakage from EVAP sys-
tem
While
ignition
switch is
OFF
2 trip
*: The threshold values vary according to the atmospheric pressure measured at EVAP monitor beginning.
The values described in the table above are based on an atmospheric pressure of 100 kPa (750.1 mmHg)
(absolute pressure).
HINT:
The 0.02 inch orifice is located inside the pump module.
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page
DI±460).
DID8I±01

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)
DI±446
± DIAGNOSTICSENGINE
640 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) after 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 then 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.

A23481
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 0.02 Inch Orifice Clogged:
OK
Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
± DIAGNOSTICSENGINE
DI±447
641 Author: Date:
2005 SEQUOIA (RM1146U)
(a) P043E: 0.02 inch orifice clogged
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The
EVAP 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 lower than ±4.85 kPa (±36.38 mmHg)*, the ECM interprets this
as a clog malfunction in the 0.02 inch orifice, and stops the EVAP (Evaporative Emission) system monitor.
The ECM then 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.

A23482
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
OK Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
EVAP Pressure when 0.02 Inch Orifice High±flow malfunction: DI±448
± DIAGNOSTICSENGINE
642 Author: Date:
2005 SEQUOIA (RM1146U)
(b) P043F: 0.02 inch orifice high±flow
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The
EVAP 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)*, the ECM interprets this as
a high±flow malfunction in the 0.02 inch orifice, and stops the EVAP system monitor. The ECM then illumi-
nates 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 a atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
MONITOR STRATEGY
RltdDTCP043E0.02 inch orifice clog (built±in pump module)Related DTCsP043F0.02 inch orifice high±flow (built±in pump module)
Required sensors/componentsPump module
Frequency of operationOnce per driving cycle
DurationWithin 2 min. (varies with amount of fuel in tank)
MIL operation2 driving cycle
Sequence of operationNone

± DIAGNOSTICSENGINE
DI±449
643 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 values when atmo-
spheric 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)±
4. Vacuum introduction and leak±

DI±450
± DIAGNOSTICSENGINE
644 Author: Date:
2005 SEQUOIA (RM1146U) Next sequence is run if both of following
conditions set
Condition 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)
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
Following values are when atmospheric pressure is 760
mmHg (100 kPa)±
One of the following conditions is met±
FTP when 4 sec. after reference pressure measurement
beganMore than ±7.5 mmHg (±1 kPa)
Reference pressureLess than ±36.38 mmHg (±4.85 kPa)
Reference pressure±7.93 mmHg (±1.057 kPa) or more
Reference pressureNot saturated
Reference pressure difference between first and second5.3 mmHg (0.7 kPa) or more
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).

A23458
Air±fuel Ratio Sensor Output:
Active A/F Control
A/F Sensor Output
Fuel Injection VolumeON
OFF
NormalMalfunction 10 Seconds
± DIAGNOSTICSENGINE
DI±451
645 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2A00 A/F Sensor Circuit Slow Response (Bank 1
Sensor 1)
DTC P2A03 A/F Sensor Circuit Slow Response (Bank 2
Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P2195 on page DI±383.
DTC No.DTC Detection ConditionsTrouble Areas
P2A00
P2A03Calculated test value for A/F sensor response rate deteriora-
tion level is less than threshold.
Open or short in A/F sensor (sensor 1) circuit

A/F sensor (sensor 1)

ECM
MONITOR DESCRIPTION
After engine is warmed up, the ECM performs air±fuel ratio feedback control to regulate the air±fuel ratio
at stoichiometric ratio. In addition, this vehicle performs Active A/F Ratio Control for approximately 10 se-
conds after preconditions met in order to measure the A/F sensor response rate. During active air±fuel ratio
control, the ECM forcibly increases and decreases the injection volume for certain amount based on learned
stoichiomentric air ±fuel ratio during usual air±fuel feedback control, and measures the A/F sensor response
rate. The ECM calculates the signal from the A/F sensor while value for A/F sensor response rate deteriora-
tion level.
If the test value for A/F sensor response rate deterioration level is less than threshold, ECM interprets this
as a malfunction, and sets the DTC.
DIDFY±01