p0120 TOYOTA SEQUOIA 2001 Service Repair Manual

DID80±01
DI±46
± DIAGNOSTICSENGINE
240 Author: Date:
2005 SEQUOIA (RM1146U)
FAIL±SAFE CHART
If any of the following code is recorded, the ECM enters fail±safe mode.
DTC No.Fail±Safe OperationFail±Safe Deactivation Conditions
P0031
P0032
P0037
P0038
P0051
P0052
P0057
P0058
The heater circuit in which an abnormality is detected is
turned offIgnition switch OFF
P0100
P0102
P0103Ignition timing is calculated from engine speed and throttle
angleºPassº condition detected
P0110
P0112
P0113
Intake air temperature is fixed at 20°C (68°F)ºPassº condition detected
P0115
P0117
P0118
Engine coolant temperature is fixed at 80°C (176°F)ºPassº condition detected
P0120
P0121
P0122
P0123
P0220
P0222
P0223
P0607
P0657
P2102
P2103
P2111
P2112
P2118
P2119
P2135
If the Electronic Throttle Control System (ETCS) has a mal-
function, 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 control-
ling the fuel injection (intermittent fuel±cut) and ignition tim-
ing in accordance with the accelerator pedal opening angle
to enable the vehicle to continue at a minimal speed.
If the accelerator pedal is depressed firmly and slowly, the
vehicle can be driven slowly. If the accelerator pedal is
depressed quickly, the vehicle may speed up and slow
down erratically.
ºPassº condition is detected and then the ignition switch is
turned OFF.
P0325
P0330Max. timing retardationIgnition switch OFF
P0351
P0352
P0353
P0354
P0355
P0356
P0357
P0358
Fuel cutºPassº condition detected

± DIAGNOSTICSENGINE
DI±59
253 Author: Date:
2005 SEQUOIA (RM1146U)P0051
(DI±88)
Oxygen (A/F) Sensor Heater
Control Circuit Low (Bank 2 Sen-
sor 1)
Open in heater circuit of A/F sensor

A/F sensor heater

A/F relay

ECM

P0052
(DI±88)Oxygen (A/F) Sensor Heater
Control Circuit High (Bank 2
Sensor 1)
Short in heater circuit of A/F sensor

A/F sensor heater

A/F relay

ECM

P0057
(DI±93)Oxygen Sensor Heater Control
Circuit Low (Bank 2 Sensor 2)

Open in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

EFI relay

ECM

P0058
(DI±93)Oxygen Sensor Heater Control
Circuit High (Bank 2 Sensor 2)

Short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

EFI relay

ECM

P0100
(DI±102)Mass or Volume Air Flow Circuit

Open or short in mass air flow meter circuit

Mass air flow meter

ECM

P0101
(DI±110)Mass or Volume Air Flow Circuit
Range/Performance Problem
Mass air flow meter
P0102
(DI±102)Mass or Volume Air Flow Circuit
Low Input
Open or short in mass air flow meter circuit

Mass air flow meter

ECM

P0103
(DI±102)Mass or Volume Air Flow Circuit
High Input
Open or short in mass air flow meter circuit

Mass air flow meter

ECM

P0110
(DI±113)Intake Air Temperature Circuit

Open or short in intake air temperature sensor circuit

Intake air temperature sensor (built in mass air flow meter)

ECM

P0112
(DI±113)Intake Air Temperature Circuit
Low Input
Open or short in intake air temperature sensor circuit

Intake air temperature sensor (built in mass air flow meter)

ECM

P0113
(DI±113)Intake Air Temperature Circuit
High Input
Open or short in intake air temperature sensor circuit

Intake air temperature sensor (built in mass air flow meter)

ECM

P0115
(DI±119)Engine Coolant Temperature Cir-
cuit
Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM

P0116
(DI±125)Engine Coolant Temperature Cir-
cuit Range/Performance Prob-
lem

Engine coolant temperature sensor
P0117
(DI±119)Engine Coolant Temperature Cir-
cuit Low Input
Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM

P0118
(DI±119)Engine Coolant Temperature Cir-
cuit High Input
Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM

P0120
(DI±127)Throttle/Pedal Position Sensor/
Switch ºAº Circuit
Open or short in throttle control motor and sensor circuit

Throttle control motor and sensor

ECM

P0121
(DI±137)Throttle/Pedal Position Sensor/
Switch ºAº Circuit Range/Perfor-
mance Problem

Throttle control motor and sensor

± DIAGNOSTICSENGINE
DI±127
321 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit
DTC P0122 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Low Input
DTC P0123 Throttle/Pedal Position Sensor/Switch ºAº
Circuit High Input
DTC P0220 Throttle/Pedal Position Sensor/Switch ºBº
Circuit
DTC P0222 Throttle/Pedal Position Sensor/Switch ºBº
Circuit Low Input
DTC P0223 Throttle/Pedal Position Sensor/Switch ºBº
Circuit High Input
DTC P2135 Throttle/Pedal Position Sensor/Switch
ºAº/ºBº Voltage Correction
HINT:
This is the purpose for the ºthrottle position sensorº.
DID84±01

± DIAGNOSTICSENGINE
DI±129
323 Author: Date:
2005 SEQUOIA (RM1146U)DTC No.
DTC Detection Condition
Condition (a) of DTC P0120, P0122, P0123, P0220, P0222 or P0223 continues
for 2 sec.
(Open or short in the throttle control motor and sensor circuit)Trouble Area
P0120
Detection conditions for DTCs P0122 and P0123 are not satis-
fied but condition (a) is satisfied
(a) VTA1 is º0.2 V or lessº or VTA1 is º4.8 V or moreº
Open or short in throttle control motor and sensor circuit

Throttle control motor and sensor

ECM
P0122(a) VTA1 is 0.2 V or less

Short in throttle control motor and sensor circuit

Throttle control motor and sensor

Short in VTA1 circuit

Open in VC circuit

ECM
P0123(a) VTA1 is 4.8 V or more

Open in throttle control motor and sensor circuit

Throttle control motor and sensor

Open in VTA1 circuit

Open in E2 circuit

VC and VTA1 circuit are short±circuited

ECM
P0220
Detection conditions for DTCs P0222 and P0223 are not satis-
fied but condition (a) is satisfied
(a) VTA2 is º0.5 V or lessº or VTA2 is º4.8 V or moreº
Throttle control motor and sensor

ECM
P0222(a) VTA2 is 0.5 V or less

Throttle control motor and sensor

Short in VTA2 circuit

Open in VC circuit

ECM
P0223(a) VTA2 is º4.8 V or moreº and
VTA1 is º0.2 V or moreº and VTA1 is º1.8 V or lessº

Throttle control motor and sensor

Open in VTA2 circuit

Open in E2 circuit

VC and VTA2 circuit are short±circuited

ECM
P2135
Condition (a) continues for 0.5 sec. or more, or
condition (b) continues for 0.4 sec. or more:
(a) Difference between VTA1 and VTA2 is 0.02 V or less
(b) VTA1 is º0.2 V or lessº and VTA2 is º0.5 V or lessº
VTA1 and VTA2 circuit are short±circuited

Throttle control motor and sensor

ECM
HINT:

After confirming DTCs, use the hand±held tester or the OBD II scan tool to confirm the throttle valve
opening percentage and closed throttle position switch condition.

THROTTLE POS means the VTA1 signal and the THROTTLE POS #2 means the VTA2 signal.
Reference (Normal condition):
Tester displayAccelerator pedal fully releasedAccelerator pedal fully depressed
THROTTLE POS10 to 24%66 to 98%
THROTTLE POS #22.1 to 3.1 V4.5 to 5.5 V

DI±130
± DIAGNOSTICSENGINE
324 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The ECM uses throttle position sensor to monitor the throttle valve opening angle.
(a) There is an expected specific voltage difference between VTA1 and VTA2 for each throttle opening
angle.

If the difference between VTA1 and VTA2 is incorrect the ECM interprets this as a fault and will set a
DTC.
(b) VTA1 and VTA2 each have a specific voltage operating range.

If VTA1 or VTA2 is out of the normal operating range the ECM interprets this as a fault and will set a
DTC.
(c) VTA1 and VTA2 should never be close to the same voltage levels.

If VTA1 is within the range of ± 0.02 V of VTA2 the ECM interprets this as a short circuit in the throttle
position sensor system and will set a DTC.
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
P0120Throttle position sensor (sensor 1) range check
(Fluttering)
P0122Throttle position sensor (sensor 1) range check
(Low voltage)
P0123Throttle position sensor (sensor 1) range check
(High voltage)
Related DTCsP0220Throttle position sensor (sensor 2) range check
(Fluttering)
P0222Throttle position sensor (sensor 2) range check
(Low voltage)
P0223Throttle position sensor (sensor 2) range check
(High voltage)
P2135Throttle position sensor range check (Correla-
tion)
Required sensors/componentsThrottle position sensor
Frequency of operationContinuous
Duration
Accelerator pedal ON: 2 sec.
Accelerator pedal OFF: 10 sec.
P2135: 0.5 sec. or 0.4 sec.
MIL operationImmediate
Sequence of operationNone

± DIAGNOSTICSENGINE
DI±131
325 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these
DTCs are not presentSee page DI±18
Throttle control motor powerON
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0120:
VTA1 voltage0.2 V or less, or 4.8 V or more
P0122:
VTA1 voltage0.2 V or less
P0123:
VTA1 voltage4.8 V or more
P0220:
VTA2 voltage0.5 V or less, or 4.8 V or more
P0222:
VTA2 voltage0.5 V or less
P0223:
Both of the following conditions are met for 2 sec. or more:Condition 1 and 2
1. VTA1 voltage0.2 to 1.8 V
2. VTA2 voltage4.8 V or more
P2135:
Different between VTA1 and VTA2 voltage0.02 V or less
Both of the following conditions are met:Condition 1 and 2
1. VTA1 voltage0.2 V or less
2. VTA2 voltage0.5 V or less
COMPONENT OPERATING RANGE
ParameterStandard Value
Throttle position sensor VTA1 voltage0.6 to 3.96 V
Throttle position sensor VTA2 voltage2.25 to 5.0 V

B17411
E2 VC
E8ECM Connector
± DIAGNOSTICSENGINE
DI±135
329 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check voltage between terminals VC and E2 of ECM connector.
PREPARATION:
(a) Disconnect the T14 throttle control motor and sensor con-
nector.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between the specified terminals of the E8
ECM connector.
OK:
Standard:
Tester ConnectionSpecified Condition
VC (E8±23) ± E2 (E8±28)4.5 to 5.5 V
NG Replace ECM (See page SF±80).
OK
4 Replace throttle body (See page SF±42).
Go
5 Check if DTC output recur.
PREPARATION:
(a) Clear the DTC (See page DI±43).
(b) Start the engine.
(c) Run the engine at idle for 15 seconds or more.
CHECK:
Read the DTC.
RESULT:
Display (DTC Output)Proceed to
ºP0120, P0122, P0123, P0220, P0222, P0223 and/or P2135º are output
againA
No DTC outputB
B System is OK.
A

± DIAGNOSTICSENGINE
DI±137
331 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0121 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Range/Performance Problem
HINT:
This is the purpose of the ºthrottle position sensorº.
CIRCUIT DESCRIPTION
Refer to DTC P0120 on page DI±127.
DTC No.DTC Detecting ConditionTrouble Area
P0121
Condition (a) continues for 2.0 sec.:
(a) Difference between VTA1 and VTA2 deviates from the
threshold
Throttle control motor and sensor
MONITOR DESCRIPTION
The ECM uses throttle position sensor to monitor the throttle valve opening angle.
This sensor includes two signals, VTA1 and VTA2. VTA1 is used to detect the throttle opening angle and
VTA2 is used to detect malfunctions in VTA1. There are several checks that the ECM performs confirm prop-
er operation of the throttle position sensor and VTA1.
There is a specific voltage difference expected between VTA1 and VTA2 for each throttle opening angle.
If the voltage output difference of the VTA1 and VTA2 deviates from the normal operating range, the ECM
interprets this as a malfunction of the throttle position sensor. 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.
MONITOR STRATEGY
Related DTCsP0121Throttle position sensor rationality
Required sensors/componentsThrottle position sensor
Frequency of operationContinuous
Duration2 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
VTA2 voltage±4.6 V
DI3HR±14

± DIAGNOSTICSENGINE
DI±355
549 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
RltdDTC
P2102Throttle actuator control motor current
(Low current)
Related DTCs
P2103Throttle actuator control motor current
(High current)
Required sensors/componentsThrottle actuator motor
Frequency of operationContinuous
Duration2 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
P2102:
Throttle motorON
Duty±cycle ratio to open throttle actuator80%±
Throttle actuator power supply8 V±
Current motor current ± Motor current at
0.016 sec. before±0.2 A
P2103:
Throttle motorON
Either of the following conditions is met:Condition 1 or 2
1. Throttle actuator power supply8 V±
2. Throttle actuator powerON
Battery voltage8 V±
StarterOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P2102:
Throttle motor currentLess than 0.5 A (when motor drive duty 80% or more)
P2103:
Throttle motor currentMore than 10 A (0.1 sec.)
More than 7 A (0.6 sec.)
WIRING DIAGRAM
Refer to DTC P0120 on page DI±127.

± DIAGNOSTICSENGINE
DI±359
553 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
RltdDTCP2111Throttle motor actuator lock (Open)Related DTCsP2112Throttle motor actuator lock (Closed)
Rid / tMain sensors/componentsThrottle actuator motorRequired sensors/componentsRelated sensors/componentsThrottle position sensor
Frequency of operationContinuous
Duration0.5 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
P2111:
Throttle motor current2 A±
Throttle motor duty to close side80%±
P2112:
Throttle motor current2 A±
Throttle motor duty to open side80%±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
|Current throttle position sensor voltage at this time ± throttle
position sensor voltage 0.016 sec. earlier|Less than 0.1 V when throttle motor open (or close) duty 80% or more
WIRING DIAGRAM
Refer to DTC P0120 on page DI±127.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when
a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was
running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, as well as other
data from the time when a malfunction occurred.