2001 TOYOTA SEQUOIA O2 sensor

± DIAGNOSTICSENGINE
DI±309
503 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P1440 Secondary Air Injection System Control
Valve Circuit Bank 1
DTC P1443 Secondary Air Injection System Control
Valve Circuit Bank 2
CIRCUIT DESCRIPTION
Refer to DTC P0412 on page DI±234.
DTC No.DTC Detection ConditionTrouble Area
P1440
AIV1 terminal voltage becomes less than half of the +B voltage
while the VSV for air injection control is not operating.
(1 trip detection logic)
Open or short in VSV for air injection control circuit (Bank 1)

VSV power source

VSV for air injection control (Bank 1)

ECM
P1443
AIV2 terminal voltage becomes less than half of the +B voltage
while the VSV for air injection control is not operating.
(1 trip detection logic)
Open or short in VSV for air injection control circuit (Bank 2)

VSV power source

VSV for air injection control (Bank 2)

ECM
MONITOR DESCRIPTION
The ECM detects an open or short in the circuit of the VSV for air injection control according to the AIV1
(AIV2) terminal voltage, stores the DTC, and then illuminates the MIL. When the AIV1 (AIV2) terminal voltage
is less than half of the +B voltage while the VSV for air injection control is not operating, the ECM determines
it as a malfunction.
MONITOR STRATEGY
RltdDTC
P1440Secondary air injection system control valve cir-
cuit (Bank 1) range check
Related DTCs
P1443Secondary air injection system control valve cir-
cuit (Bank 2) range check
Required sensors/componentsVSV for air injection control
Frequency of operationContinuous
Duration0.5 sec.
MIL operationImmediate
Sequence of operationNone
DIDMQ±01

DI±314
± DIAGNOSTICSENGINE
508 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P1441 Secondary Air Injection System Switching
Valve No.2 Stuck Open Bank 1
DTC P1444 Secondary Air Injection System Switching
Valve No.2 Stuck Open Bank 2
DTC P2440 Secondary Air Injection System Switching
Valve Stuck Open Bank 1
CIRCUIT DESCRIPTION
Refer to DTC P0412 on page DI±234.
DTC No.DTC Detection ConditionTrouble Area
P1441
Air switching valve No.2 (bank 1) stuck open:
The pressure sensor detects exhaust pulsation, when both of
air switching valve No.2 are OFF (and air switching valve ON).
(2 trip detection logic)
VSV for air injection control circuit (Bank 1)

Air switching valve No.2 (Bank 1)

VSV for air injection system (Bank 1)

ECM
P1444
Air switching valve No.2 (bank 2) stuck open:
The pressure sensor detects exhaust pulsation, when both of
air switching valve No.2 are OFF (and air switching valve ON).
(2 trip detection logic)
VSV for air injection control circuit (Bank 2)

Air switching valve No.2 (Bank 2)

VSV for air injection system (Bank 2)

ECM
P2440
Air switching valve stuck open:
The pressure sensor detects exhaust pulsation when the sys-
tem does not operate (both of air switching valve No.2 OFF,
and air switching valve OFF and air pump OFF).
This DTC means open stuck of air switching valve and ºair
switching valve No.2 (bank 1 or bank 2)º
(1 trip detection logic)
Air switching valve

Air switching valve No.2 (Bank 1 and/or 2)

VSV for air injection system (Bank 1 and/or 2)

Air injection driver

Air injection driver circuit

ECM
DIDMR±01

B17424
Monitor Operation Outline
Running
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF Engine
Air pump
ASV
(Electromagnetic Type)
ASV No.2 (Bank 1)
(Vacuum Type)*
System Air Pressure ASV No.2 (Bank 2)
(Vacuum Type)*
AB C D E F
*: ASV No.2 opens alternately per a trip.
± DIAGNOSTICSENGINE
DI±315
509 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The ECM detects pressure change with the pressure sensor to determine malfunctioning parts in the system,
and stores the DTCs. The ECM measures pressure and/or exhaust pulsation of the system at 6 points, A
to F, when the air injection system is in operation or when not in operation. When the pressure is high, the
ECM determines the that pump operates. When exhaust pulsation is detected, the ECM determines that the
ASV is open. The ECM determines malfunction parts based on the measured value, and stores the DTCs.
Points A and B:
ECM detects pressure changes (decrease), and determines that the ASV No.2 is open.
Points C and F:
ECM detects pressure and exhaust pulsation, and determines the pressure pattern of the system.
Point D:
ECM operates the system, as indicated by the dashed lines, to determine which of the ASV No.2 is malfunc-
tioning only when pressure changes cannot be detected at point A or B.
Point E:
ECM detects exhaust pulsation to determine the condition of the system.
Pressure condition in Secondary Air Injection System (Point C and F)
Pattern 1:
Air PumpON
Air Switching Valve and Air Switching Valve No.2Open
Pressure1 kPa or more
Pulsation detectionExhaust gas pulsation detected

± DIAGNOSTICSENGINE
DI±317
511 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P1441Air switching valve No. 2 (Bank 1) is stuck open
Related DTCsP1444Air switching valve No. 2 (Bank 2) is stuck openRelated DTCs
P2440Air switching valve and air switching valve No. 2
are stuck open
Required sensors/componentsPressure sensor, Air switching valve No. 2 (Bank 1, 2), Electromagnetic air switching valve
Frequency of operationContinuous
Duration
P1441 (Air switching valve No. 2 (Bank 1) is stuck open): 20 sec.
P1444 (Air switching valve No. 2 (Bank 2) is stuck open): 20 sec.
P2440 (Air switching valve and air switching valve No. 2 are stuck open): 18 sec.
MIL operation
P1441 (Air switching valve No. 2 (Bank 1) is stuck open): 2 driving cycles
P1444 (Air switching valve No. 2 (Bank 2) is stuck open): 2 driving cycles
P2440 (Air switching valve and air switching valve No. 2 are stuck open):
1 driving cycle
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
P1441, P1444: Air switching valve No. 2 bank 1 and/or bank 2 are stuck open
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
CASE 1
Atmospheric pressure76 kPa (570 mmHg)±
Battery voltage11.5 V±
Time after secondary air injection out of
operation10 sec.±
AIR pumpOFF
Time after engine start10 sec.±
Air switching valve No. 2 (Bank 1)OFF
Air switching valve No. 2 (Bank 2)OFF
Air injection pressure sensor failNot detected
Air switching valveON
Engine RPM±3,750 rpm
CASE 2
Atmospheric pressure76 kPa (570 mmHg)±
Battery voltage11.5 V±
AIR pumpOFF
Time after engine start10 sec.±
Air switching valve No. 2 (Bank 1)OFF
Air switching valve No. 2 (Bank 2)OFF
Air injection pressure sensor failNot detected
Engine load0%±
Intake air amount40 g/sec±
IAT at engine start±15°C (5°F)±
ECT at engine start±5°C (41°F)

DI±318
± DIAGNOSTICSENGINE
512 Author: Date:
2005 SEQUOIA (RM1146U) Air switching valve
ON
Engine RPM±3,750 rpm
P2440: Electromagnetic air switching valve and air switching valve No. 2 are stuck open
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Atmospheric pressure76 kPa (570 mmHg)±
Battery voltage11.5 V±
Time after secondary air injection out of
operation10 sec.±
Cumulative intake air amount172 g±
AIR pumpOFF
Air switching valveOFF
Air switching valve No. 2 (Bank 1)OFF
Air switching valve No. 2 (Bank 2)OFF
Engine RPM±3,750 rpm
Air injection pressure sensor failNot detected
TYPICAL MALFUNCTION THRESHOLDS
P1441, P1444: Air switching valve No. 2 bank 1 and/or bank 2 are stuck open
Detection CriteriaThreshold
CASE 1:
Both of the following conditions are metCondition (a) and (b)
(a) Cumulative pressure pulsation (When AI OFF)20 kPa (150 mmHg) or more
(b) Air pressure change (When ASV No.2 open)
(P1441 (Bank 1), P1444 (Bank 2))Less than 1 kPa (7.5 mmHg) or more
CASE 2:
Detected times of identifying condition 1 is met4 times or more
1. Cumulative pressure pulsation100 kPa (750 mmHg) or more
P2440: Electromagnetic air switching valve and air switching valve No. 2 are stuck open
Detection CriteriaThreshold
Detected times of identifying condition 1 is met4 times or more
1. Cumulative pressure pulsation100 kPa (750 mmHg) or more

DI±330
± DIAGNOSTICSENGINE
524 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P1442 Secondary Air Injection System Switching
Valve No.2 Stuck Close Bank 1
DTC P1445 Secondary Air Injection System Switching
Valve No.2 Stuck Close Bank 2
DTC P2441 Secondary Air Injection System Switching
Valve Stuck Close Bank 1
CIRCUIT DESCRIPTION
Refer to DTC P0412 on page DI±234.
DTC No.DTC Detection ConditionTrouble Area
P1442
Air switching valve No.2 (bank 1) stuck close:
No pressure change (decrease) after the ECM sends an open
air switching valve No.2 (bank 1) signal.
(2 trip detection logic)

VSV for air injection control circuit (Bank 1)

Vacuum hose (VSV for air injection control ± air switching
valve No.2)

Air injector pipe (Air switching valve No.2 ± exhaust manifold)

Air switching valve No.2 (Bank 1)

VSV for air injection control (Bank 1)

ECM
P1445
Air switching valve No.2 (bank 2) stuck close:
No pressure change (decrease) after the ECM sends an open
air switching valve No.2 (bank 2) signal.
(2 trip detection logic)

VSV for air injection control circuit (Bank 2)

Vacuum hose (VSV for air injection control ± air switching
valve No.2)

Air injector pipe (Air switching valve No.2 ± exhaust manifold)

Air switching valve No.2 (Bank 2)

VSV for air injection control (Bank 2)

ECM
P2441
Air switching valve stuck close:
The pressure sensor does not detect exhaust pulsation when
system operates. (All of air switching valve ON)
This DTC means either of following conditions.
(a) Electromagnetic air switching valve stuck closed.
(b) Both of ºair switching valve No.2 bank 1º and ºair switching
valve No.2 bank 2º stuck closed.
(2 trip detection logic)
Vacuum hoses (Throttle body ± VSVs for air injection control)

Air switching valve

Air injector pipe (Air switching valve No.2 ± exhaust manifold)

Air injection hose

Air switching valve No.2 (Bank 1 and/or 2)

VSV for air injection control (Bank 1 and/or 2)

Air injection driver

Air injection driver circuit

ECM
MONITOR DESCRIPTION
Refer to DTC P1441, P1444 and P2440 on page DI±314.
DIDMS±01

± DIAGNOSTICSENGINE
DI±331
525 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P1442Air switching valve No. 2 (Bank 1) is stuck closed
Related DTCsP1445Air switching valve No. 2 (Bank 2) is stuck closedRelated DTCs
P2441Air switching valve and air switching valve No.2
are stuck closed
Required sensors/componentsPressure sensor, Air switching valve No. 2 (Bank 1, 2), Electromagnetic air switching valve
Frequency of operationContinuous
Duration
P1442 (Air switching valve No. 2 (Bank 1) is stuck closed): 20 sec.
P1445 (Air switching valve No. 2 (Bank 2) is stuck closed): 20 sec.
P2441 (Air switching valve is stuck closed): 8 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
P1442, P1445: Air switching valve No. 2 bank 1 and/or bank 2 are stuck closed
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Atmospheric pressure76 kPa (570 mmHg)±
Battery voltage11.5 V±
IdleON
Engine RPM±3,750 rpm
Time after secondary air injection out of
operation10 sec.±
Air injection pressure sensor failNot detected
P2441: Electromagnetic air switching valve is stuck closed or air switching valve No. 2 (Bank 1 and
Bank 2) are stuck closed
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Atmospheric pressure76 kPa (570 mmHg)±
Battery voltage11.5 V±
Time after secondary air injection in op-
eration6 sec.±
AIR pumpON
Air switching valveON
Air switching valve No. 2 (Bank 1)ON
Air switching valve No. 2 (Bank 2)ON
Engine RPM±3,750 rpm
Delay time after engine started6 sec.±
Air injection pressure sensor failNot detected

DI±344
± DIAGNOSTICSENGINE
538 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
Related DTCsP1613Secondary air injection system control module
range check
Required sensors/componentsAir injection driver
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Case 1:
Battery voltage8 V±
Ignition switchON
StarterOFF
Case 2:
Either of following conditions is metCondition 1 or 2
1. Air pumpNot operating
2. Air switching valveNot operating
Battery voltage8 V±
Ignition switchON
StarterOFF
Case 3:
Air pumpOperating
Air switching valveOperating
Battery voltage8 V±
Ignition switchON
StarterOFF
Case 4:
Battery voltage8 V±
Ignition switchON
StarterOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Case 1:
One of the following conditions is metCondition 1, 2, 3 or 4
1. Diagnostic signal duty ratio from air injection driver1 to 10 %
2. Diagnostic signal duty ratio from air injection driver30 %
3. Diagnostic signal duty ratio from air injection driver49 %
4. Diagnostic signal duty ratio from air injection driver91 to 99 %
Case 2:
Diagnostic signal duty ratio from air injection driver70 to 90 %