Toyota 2GR-FE Manual page 505

DTC P2121
DESCRIPTION
This ETCS (Electronic Throttle Control System) does not use a throttle cable.
The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal bracket and has 2
sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type, and uses Hall-effect
elements, in order to yield accurate signals, even in extreme driving conditions, such as at high speeds as
well as very low speeds. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies
between 0 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal
from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used
for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP
sensor itself.
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the
signals from VPA and VPA2, and controls the throttle actuator according to these signals.
Accelerator Pedal Position Sensor
Magnet
VPA
IC No. 1
EPA
VCPA
VPA2
EPA2
VCP2
IC No. 2
Magnet
DTC No.
Difference between VPA and VPA2 is less than 0.4 V, or
P2121
more than 1.2 V for 0.5 seconds (1 trip detection logic)
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
Throttle / Pedal Position Sensor / Switch "D"
Circuit Range / Performance
ECM
3.4 to 5.0
2.6 to 4.5
DTC Detection Condition
Accelerator Pedal Position Sensor Output Voltage (V)
*1
5
1.6
0.8
Usable Range
0
Accelerator Pedal Turning Angle (deg)
*1: Accelerator Pedal Fully Released
*2: Accelerator Pedal Fully Depressed
• Accelerator Pedal Position (APP) sensor
• ECM
ES–349
*2
25
A019803E27
Trouble Area
ES