2001 TOYOTA SEQUOIA ESP

DI±224
± DIAGNOSTICSENGINE
418 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P0351No. 1 ignition coil with igniter circuit malfunction
P0352No. 2 ignition coil with igniter circuit malfunction
P0353No. 3 ignition coil with igniter circuit malfunction
RltdDTCP0354No. 4 ignition coil with igniter circuit malfunctionRelated DTCsP0355No. 5 ignition coil with igniter circuit malfunction
P0356No. 6 ignition coil with igniter circuit malfunction
P0357No. 7 ignition coil with igniter circuit malfunction
P0358No. 8 ignition coil with igniter circuit malfunction
Required sensors/componentsIgniter
Frequency of operationContinuous
Duration0.256 sec. + 4 sparks
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Engine speed±1,500 rpm
Either of the following conditions is met:Condition 1 or 2
1. Following conditions are met:Condition (a) and (b)
(a) Engine speed±500 rpm
(b) Battery voltage6 V±
2. Following conditions are met:Condition (a) and (b)
(a) Engine speed500 rpm±
(b) Battery voltage10 V±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
ºIgnition signal fail countºMore than 2
ºIgnition signal fail countº is on the right:When IGF does not return despite sending IGT.
COMPONENT OPERATING RANGE
Standard Value
Confirmed signal number = ignition signal number

± DIAGNOSTICSENGINE
DI±235
429 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The air injection driver (AID) detects an open or short in the circuit according to the voltage of the air pump
terminal (VP) and electromagnetic air switching valve terminal (VV), and sends a signal as diagnostic in-
formation to the ECM.
The AID outputs the air switching valve terminal malfunction signal to the ECM if: 1) VV terminal voltage is
low despite the AID receiving the command signal from the ECM to drive the air switching valve terminal or
2) VV terminal voltage is high despite the AID not receiving the command signal from the ECM.
The ECM stores the DTC based on the diagnostic signal from the AID and illuminates the MIL.
MONITOR STRATEGY
Related DTCsP0412Air switching valve circuit malfunction (Second-
ary air injection system)
Required sensors/componentsAir injection driver, Air switching valve
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:
Air pumpOperating
Air switching valveOperating
Battery voltage8 V±
Ignition switchON
StarterOFF
Case 2:
Air pumpNot operating
Air switching valveNot operating
Battery voltage8 V±
Ignition switchON
StarterOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Case 1, 2:
Diagnostic signal duty ratio from air injection driver31 to 48 %
COMPONENT OPERATING RANGE
ParameterStandard Value
Diagnostic signal duty ratio from air injection driver
70 to 90% when secondary air injection system operating
and
0% when secondary air injection system not operating

DI±242
± DIAGNOSTICSENGINE
436 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0418 Air Injection System Air Pump Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P0412 on page DI±234.
DTC No.DTC Detection ConditionTrouble Area
P0418
All of the following conditions are met, when idling just after
cold start. (1 trip detection logic):
(a) Air injection system not operate
(b) Air injection driver outputs air pump malfunction signal (20%
duty signal)
Open in air pump drive circuit

Short between air pump circuit and +B circuit

Air injection driver

ECM
P0418
All of the following conditions are met, when idling just after
cold start.
(1 trip detection logic):
(a) Air injection system operates
(b) Air injection driver outputs air pump malfunction signal (20%
duty signal)

Short between air pump circuit and body ground

Air injection driver

ECM
MONITOR DESCRIPTION
Air Injection Driver (AID) detects an open or short in the air pump and Air Switching Valve (ASV) circuit ac-
cording to the terminal voltage and sends a signal as diagnostic information to the ECM.
When the air injection system operation is required while the engine is warming up, the ECM transmits com-
mand signals to the AID to drive the air pump and ASV.
The AID inputs the command signal from ECM if: 1) VP terminal voltage is low despite the AID inputting the
command signal from the ECM to drive the ASV or 2) VP terminal voltage is high despite the AID not inputting
the command signal from the ECM.
The ECM sets the DTC based on the diagnostic information from the AID.
MONITOR STRATEGY
Related DTCsP0418Air pump range check
Required sensors/componentsAir injection driver, Air pump
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate
Sequence of operationNone
DIDMW±01

DI±354
± DIAGNOSTICSENGINE
548 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2102 Throttle Actuator Control Motor Circuit Low
DTC P2103 Throttle Actuator Control Motor Circuit High
CIRCUIT DESCRIPTION
The throttle motor is operated by the ECM. It opens and closes the throttle valve.
The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the
throttle body. The throttle position sensor provides feedback to the ECM. This feedback allows the ECM to
control the throttle motor and monitor the throttle opening angle as the ECM responds to driver inputs.
HINT:
This Electrical Throttle Control System (ETCS) does not use a throttle cable.
DTC No.DTC Detection ConditionTrouble Area
P2102
Conditions (a) and (b) continue for 2.0 seconds:
(1 trip detection logic)
(a) Throttle control motor output duty 80 % or more
(b) Throttle control motor current less than 0.5 A or less
Open in throttle control motor and sensor circuit

Throttle control motor and sensor

ECM
P2103
Either of the following condition is met.
(1 trip detection logic)
(a) Throttle control motor current 10 A or more (0.1 sec)
(b) Throttle control motor current 7 A or more (0.6 sec.)
Short in throttle control motor and sensor circuit

Throttle control motor and sensor

Throttle valve

Throttle body

ECM
MONITOR DESCRIPTION
The ECM monitors the current through the electronic throttle motor and detects malfunctions or open circuit
in the throttle motor based on the voltage of the current. When the current deviates from the standard, the
ECM concludes that there is a fault in the throttle motor.
Or, if the throttle valve is not functioning properly (for example, stuck ON), the ECM concludes that there is
a fault, turns on the MIL and sets a DTC is set.
Example:
When the current is more than 10 A. Or the current is less than 0.5 A when the motor driving duty ratio is
exceeding 80%. The ECM concludes that the current is out of range, turns on the MIL and a DTC is set.
FAIL SAFE
If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle
control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by
the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (inter-
mittent fuel±cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the
vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a ºpassº condition is detected and then the ignition switch is turned OFF, the fail±safe operation will stop
and the system will return to normal condition.
DICF9±02

DI±358
± DIAGNOSTICSENGINE
552 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2111 Throttle Actuator Control System
±Stuck Open
DTC P2112 Throttle Actuator Control System
±Stuck Closed
CIRCUIT DESCRIPTION
The throttle motor is operated by the ECM. It opens and closes the throttle valve using gears. The opening
angle of the throttle valve is detected by the throttle position sensor, which is mounted on the throttle body.
The throttle position sensor provides feedback to the ECM to control the throttle motor and set the throttle
valve angle in response to driver input.
HINT:
This Electrical Throttle Control System (ETCS) does not use a throttle cable.
DTC No.DTC Detection ConditionTrouble Area
P2111Throttle motor locked during ECM order to close.
(1 trip detection logic)
Throttle control motor and sensor circuit

Throttle control motor and sensor
P2112Throttle motor locked during ECM order to open.
(1 trip detection logic)
Throttle control motor and sensor

Throttle body

Throttle valve
MONITOR DESCRIPTION
The ECM concludes that there is a malfunction of the ETCS (Electronic Throttle Control System) when the
throttle valve remains at a fixed angle despite high drive current from the ECM. The ECM will turn on the MIL
and a DTC is set.
FAIL SAFE
If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle
control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by
the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (inter-
mittent fuel±cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the
vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a ºpassº condition is detected and then the ignition switch is turned OFF, the fail±safe operation will stop
and the system will return to normal condition.
DICFA±02

± DIAGNOSTICSENGINE
DI±367
561 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2119 Throttle Actuator Control Throttle Body
Range/Performance
CIRCUIT DESCRIPTION
The Electric Throttle Control System (ETCS) is composed of a throttle motor that operates the throttle valve,
a throttle position sensor that detects the opening angle of the throttle valve, an accelerator pedal position
sensor that detects the accelerator pedal position, and the ECM that controls the ETCS system.
The ECM operates the throttle motor to position the throttle valve for proper response to driver inputs. The
throttle position sensor, mounted on the throttle body, detects the opening angle of the throttle valve and
provides this signal to the ECM so that the ECM can regulate the throttle motor.
DTC No.DTC Detection ConditionTrouble Area
P2119
Throttle opening angle continues to vary greatly from target
throttle opening angle
(1 trip detection logic)
Electric throttle control system

Throttle body
MONITOR DESCRIPTION
The ECM determines the ºactualº throttle angle based on the throttle position sensor signal. The ºactualº
throttle position is compared to the ºtargetº throttle position commanded by the ECM. If the difference of
these two values exceeds a specified limit, the ECM interprets this as a fault in the ETCS (Electronic Throttle
Control System). The ECM turns on the MIL and a DTC is set.
FAIL SAFE
If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle
control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by
the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (inter-
mittent fuel±cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the
vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a ºpassº condition is detected and then the ignition switch is turned OFF, the fail±safe operation will stop
and the system will return to normal condition.
MONITOR STRATEGY
Related DTCsP2119Electronic throttle control system failure
Rid / tMain sensorsThrottle actuator motorRequired sensors/componentsRelated sensorsThrottle position sensor
Frequency of operationContinuous
Duration1 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is
not presentSee page DI±18
The typical enabling condition is not avail-
able±
DICFC±02

A23473A±A Cross SectionAtmospheric AirSolid Electrolyte
(Zirconia Element)
Platinum
Electrode Heater
Exhaust Gas
Cover Element
A
A
ECM Monitored
A/F Sensor Voltage
Air±Fuel Ratio Alumina
4.0
3.0
2.0
12 13 14 15 16 17
DI±384
± DIAGNOSTICSENGINE
578 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
The A/F sensor generates a voltage* that corresponds to the actual air±fuel ratio. This sensor voltage is used
to provide the ECM with feedback so that it can control the air±fuel ratio. The ECM determines the deviation
from the stoichiometric air±fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunc-
tions, the ECM is unable to control the air±fuel ratio accurately.
The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia
element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas tempera-
ture is low), a current flows into the heater to heat the sensor, in order to facilitate accurate air±fuel ratio
detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat
generated by the heater is conducted to the solid electrolyte though the alumina, therefore the sensor activa-
tion is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide
(NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air±fuel
ratio must be precisely controlled so that it is always close to the stoichiometric level.
*: Value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted
to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a
constant voltage.

A23456
Air±fuel Ratio Sensor Current Monitor:
Fuel±cut
High Side Thresh
Low Side Thresh
3 sec. or more
Time t2
t1 3 sec.
Delay ON
OFF
Normal
Malfunction3 sec.
Delay3 sec.
Delay Sensor Current
(mA)
A/F Sensor
Current
Cumulative Time = t1 + t2 = 3 sec. or more DI±386
± DIAGNOSTICSENGINE
580 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION

Sensor voltage detection monitor:
Under the air±fuel ratio feedback control, if the A/F sensor voltage output indicates rich or lean for a
certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illu-
minates the MIL and sets a DTC.
Example:
If the A/F sensor voltage output is less than 2.8 V (very rich condition) for 10 seconds, despite the HO2
sensor voltage output being less than 0.85 V, the ECM sets DTC P2196. Alternatively, if the A/F sensor
voltage output is more than 3.8 V (very lean condition) for 10 seconds, despite the HO2 sensor voltage
output being 0.15 V or more, DTC P2195 or P2197 is set.

Sensor current detection monitor:
A rich air±fuel mixture causes a low air±fuel ratio sensor current, and a lean air fuel mixture causes
a high air fuel ratio sensor current. Therefore, the sensor output becomes high during acceleration,
and the sensor becomes low during deceleration.
The ECM monitors the air±fuel ratio sensor current during fuel±cut and detects an unusual current val-
ue. If the cumulative time the sensor output is out of range exceeds more than 3 seconds, the ECM
interprets a malfunction in the air±fuel ratio sensor and sets a DTC.