Toyota Sequoia (2005). Manual - part 81

–

DIAGNOSTICS

ENGINE

DI–127

321

DTC

P0120

Throttle/Pedal Position Sensor/Switch ”A”
Circuit

DTC

P0122

Throttle/Pedal Position Sensor/Switch ”A”
Circuit Low Input

DTC

P0123

Throttle/Pedal Position Sensor/Switch ”A”
Circuit High Input

DTC

P0220

Throttle/Pedal Position Sensor/Switch ”B”
Circuit

DTC

P0222

Throttle/Pedal Position Sensor/Switch ”B”
Circuit Low Input

DTC

P0223

Throttle/Pedal Position Sensor/Switch ”B”
Circuit High Input

DTC

P2135

Throttle/Pedal Position Sensor/Switch
”A”/”B” Voltage Correction

HINT:
This is the purpose for the ”throttle position sensor”.

DID84–01

A19755

A21037

Throttle Position Sensor

ECM

Magnet

Magnet

IC No.2

IC No.1

VC

VTA1

E2

VTA2

Throttle Position Sensor Output V

oltage 

(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

–

DIAGNOSTICS

ENGINE

322

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.

–

DIAGNOSTICS

ENGINE

DI–129

323

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 ”0.2 V or less” or VTA1 is ”4.8 V or more”

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 ”0.5 V or less” or VTA2 is ”4.8 V or more”

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 ”4.8 V or more” and 

VTA1 is ”0.2 V or more” and VTA1 is ”1.8 V or less”

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 ”0.2 V or less” and VTA2 is ”0.5 V or less”

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 display

Accelerator pedal fully released

Accelerator pedal fully depressed

THROTTLE POS

10 to 24%

66 to 98%

THROTTLE POS #2

2.1 to 3.1 V

4.5 to 5.5 V

DI–130

–

DIAGNOSTICS

ENGINE

324

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 ”pass” 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

P0120

Throttle position sensor (sensor 1) range check 
(Fluttering)

P0122

Throttle position sensor (sensor 1) range check 
(Low voltage)

P0123

Throttle position sensor (sensor 1) range check 
(High voltage)

Related DTCs

P0220

Throttle position sensor (sensor 2) range check 
(Fluttering)

P0222

Throttle position sensor (sensor 2) range check 

(Low voltage)

P0223

Throttle position sensor (sensor 2) range check 

(High voltage)

P2135

Throttle position sensor range check (Correla-

tion)

Required sensors/components

Throttle position sensor

Frequency of operation

Continuous

Duration

Accelerator pedal ON: 2 sec.
Accelerator pedal OFF: 10 sec.
P2135: 0.5 sec. or 0.4 sec.

MIL operation

Immediate

Sequence of operation

None