IN±52
± INTRODUCTIONTERMS
2001 PRIUS (RM778U) HO2S
Heated Oxygen SensorHeated Oxygen Sensor (HO2S)
IACIdle Air ControlIdle Speed Control (ISC)
IATIntake Air TemperatureIntake or Inlet Air Temperature
ICMIgnition Control Module±
IFIIndirect Fuel InjectionIndirect Injection (IDL)
IFSInertia Fuel±Shutoff±
ISCIdle Speed Control±
KSKnock SensorKnock Sensor
MAFMass Air FlowAir Flow Meter
MAPManifold Absolute PressureManifold Pressure
Intake Vacuum
MCMixture Control
Electric Bleed Air Control Valve (EBCV)
Mixture Control Valve (MCV)
Electric Air Control Valve (EACV)
MDPManifold Differential Pressure±
MFIMultiport Fuel InjectionElectronic Fuel Injection (EFI)
MILMalfunction Indicator LampCheck Engine Lamp
MSTManifold Surface Temperature±
MVZManifold Vacuum Zone±
NVRAMNon±Volatile Random Access Memory±
O2SOxygen SensorOxygen Sensor, O2 Sensor (O2S)
OBDOn±Board DiagnosticOn±Board Diagnostic System (OBD)
OCOxidation Catalytic ConverterOxidation Catalyst Convert (OC), CCo
OPOpen LoopOpen Loop
PAIRPulsed Secondary Air InjectionAir Suction (AS)
PCMPowertrain Control Module±
PNPPark/Neutral Position±
PROMProgrammable Read Only Memory±
PSPPower Steering Pressure±
PTOXPeriodic Trap OxidizerDiesel Particulate Filter (DPF)
Diesel Particulate Trap (DPT)
RAMRandom Access MemoryRandom Access Memory (RAM)
RMRelay Module±
ROMRead Only MemoryRead Only Memory (ROM)
RPMEngine SpeedEngine Speed
SCSuperchargerSupercharger
SCBSupercharger BypassE±ABV
SFISequential Multiport Fuel InjectionElectronic Fuel Injection (EFI), Sequential Injection
SPLSmoke Puff Limiter±
SRIService Reminder Indicator±
SRTSystem Readiness Test±
STScan Tool±
TBThrottle BodyThrottle Body
TBIThrottle Body Fuel InjectionSingle Point Injection
Central Fuel Injection (Ci)
TCTurbochargerTurbocharger
TCCTorque Converter ClutchTorque Converter
A02396 A02395A02624
Throttle Position Sensor
Output Voltage (V)0 1.5
Accelerator Pedal Opening Angle (deg)70 125
VTA VTA2
5
VTA2 VTA E2 VCMovable Range
Usable RangeUsable Range *1*2
*1
*2
Movable Range
Usable
Range
*2
*1
Throttle valve
fully closed
Throttle valve
fully open *
2: *
1:
VTA2 circuit open or ground short
Accelerator pedal opening position expressed as percentage and voltage
Accelerator pedal releasedAccelerator pedal depressed
THROTTLE POS THROTTLE POS #2THROTTLE POS THROTTLE POS #2
0 %
0 %
100 % 8 ± 20 %0 V
2.0 ± 2.9 V
0 V
5 V0 %
0 %
100 %0 V
4.6 ± 5.1 V
0 V
5 VTrouble area
VC circuit open
VTA circuit open or ground short
E2 circuit open 64 ± 96 %
DI±38
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Malfunction
CIRCUIT DESCRIPTION
Throttle position sensor is mounted on the throttle body and it have the 2 sensors to detect the throttle open-
ing angle and the malfunction of the throttle position sensor's own.
The voltage applied to the terminals VTA and VTA2 of the ECM changes between 0 V and 5 V in proportion
to the opening angle of the throttle valve.
The ECM judges the current opening angle of the throttle valve from these signals input from terminals VTA
and VTA2, and the ECM controls the throttle motor to make the throttle valve angle properly in response to
driving condition.
If this DTC is stored, the ECM shuts down the power for the throttle motor, and the throttle valve is fully closed
by the return spring.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a), (b), (c), (d) or (e) continues for 2.0 seconds:
(a) VTA 0.2 V
(b) VTA2 0.625 V
(c) VTA 4.8 V
(d) When VTA 0.2 V and 2.0 V, and VTA2 4.97 V
(e) VTA ± VTA2 0.02 V
Open or short in throttle position sensor circuit
Throttle position sensor
ECM
Condition (a) continues for 0.4 seconds:
(a) VTA 0.2 V and VTA2 0.5 V
HINT:
After confirming DTC P0120, use the OBD II scan tool or TOYOTA hand±held tester to confirm the accelera-
tor pedal opening position percentage.
DI2DQ±07
