TOYOTA SEQUOIA 2001 Service Repair Manual

± 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

A19755A21037
Throttle Position Sensor ECM
Magnet
Magnet
IC No.2 IC No.1
VC
VTA1
E2 VTA2Throttle Position Sensor Output Voltage (V)
Fail Safe Angle
*1
Usable Range
Throttle Valve Opening Angle (deg)84 6
0 5
2.60
2.25
0.97
0.69
Throttle Valve Fully Opened
(Throttle Position expressed as percentage
(VTA1) 64 to 96%)
Fail Safe Angle 7°
(Throttle Position expressed as percentage
(VTA1) about 10 to 24%) Throttle Valve Fully Closed
(Throttle Position expressed as percentage
(VTA1) 10 to 20%)
*1:
VTA1 VTA2 DI±128
± DIAGNOSTICSENGINE
322 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
HINT:

This Electrical Throttle Control System (ETCS) does not use a throttle cable.

This throttle position sensor is a non±contact type.
The throttle position sensor is mounted on the throttle body. It detects the opening angle of the throttle valve.
This sensor is electronically controlled and uses Hall±effect elements, so that accurate control and reliability
can be obtained. The throttle position sensor has 2 sensor elements / signal outputs: VTA1 and VTA2. VTA1
used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA1. Voltage applied
to VTA1 and VTA2 change between 0 V and 5 V in proportion to the opening angle of the throttle valve. There
are several checks that the ECM performs to confirm proper operation of the throttle position sensor and
VTA1.
The ECM judges the current opening angle of the throttle valve from these signals input from terminals VTA1
and VTA2, and the ECM controls the throttle motor to make the throttle valve angle properly in response to
driver inputs.

± 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

A19212
T14
Throttle Control Motor
and Position Sensor
4
6
1
2G±W
G±B
P±L
B±Y28
23
19
20
4
5
17 E8
P
VECM
E2
VC
VTA2
VTA1 3
5
(Shielded)
L±RM±
M+
GE01 E8
E8
E8
E8
E8
E8 DI±132
± DIAGNOSTICSENGINE
326 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs related to different system that have terminal E2 as the ground terminal are output simulta-
neously, terminal E2 may have an open circuit.

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.

± DIAGNOSTICSENGINE
DI±133
327 Author: Date:
2005 SEQUOIA (RM1146U)
1 Connect hand±held tester, and read the voltage for throttle position sensor data.
PREPARATION:
(a) Enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / THROTTLE POS
and THROTTLE POS #2.
CHECK:
Read voltage value displayed on the hand±held tester.
OK:
RESULT:
Throttle position expressed as percentage and voltage
Accelerator pedal releasedAccelerator pedal depressedTrouble areaProceed toTHROTTLE POS
(VTA1)THROTTLE POS #2
(VTA2)THROTTLE POS
(VTA1)THROTTLE POS #2
(VTA2)Trouble areaProceed to
0 %0 to 0.2 V0 %0 to 0.2 VVC circuit open
100 %4.5 to 5.5 V100 %4.5 to 5.5 VE2 circuit open
0 % or 100 %2.1 to 3.1 V
(Fail safe)0 % or 100 %2.1 to 3.1 V
(Fail safe)VTA1 circuit open or
ground shortA
about 16 %
(Fail safe)0 to 0.2 or 4.5 to 5.5 Vabout 16 %
(Fail safe)0 to 0.2 or 4.5 to 5.5 VVTA2 circuit open or
ground short
10 to 24 %2.15 to 3.05 V64 to 96 %
(Does not fail safe)4.5 to 5.5 V
(Does not fail safe)Throttle position sen-
sor circuit is normalB
B Go to step 5.
A

A21022
Throttle Control Motor and Sensor
VC VTA2VTA1
E2 Wire Harness Side
T14
Front View
B17412VC
E2
E8ECM Connector
VTA2
VTA1
DI±134
± DIAGNOSTICSENGINE
328 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check for open and short in harness and connector between ECM and throttle
position sensor.
PREPARATION:
(a) Disconnect the T14 throttle control motor and sensor con-
nector.
(b) Disconnect the E8 ECM connector.
CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VC (T14±5) ± VC (E8±18)Below 1 W
VTA1 (T14±6) ± VTA1 (E8±21)Below 1 W
VTA2 (T14±4) ± VTA2 (E8±31)Below 1 W
E2 (T14±3) ± E2 (E8±28)Below 1 W
VC (T14±5) or VC (E8±18) ±
Body ground10 kW or higher
VTA1 (T14±6) or VTA1 (E8±21) ±
Body ground10 kW or higher
VTA2 (T14±4) or VTA2 (E8±31) ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK

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

DI±136
± DIAGNOSTICSENGINE
330 Author: Date:
2005 SEQUOIA (RM1146U)
Replace ECM (See page SF±80).