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Home >> Toyota >> 2005 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis (Single Page) >> Engine Performance >> Engine Control System (SFI) (1ZZ-FE (Fwd)) - Diagnostics >> SFI System (1ZZ-FE (Ff)) >> DTC P2120, P2122, P2123, P2125, P2127: Throttle/Pedal Position Sensor/Switch "D & E" Circuit Low/High Input >> Circuit Description
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Circuit Description

HINT:

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: VPA1 (main) and VPA2 (sub). The voltage, which is applied to terminals VPA1 and VPA2 of the ECM, varies between 0V and 5V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA1 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 VPA1 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 VPA1 and VPA2, and controls the throttle actuator according to these signals.

Fig 1: Throttle Pedal Position Sensor Operating Range Diagram And Output Voltage Graph
G02661859Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig 2: DTC Trouble Detection Chart (DTC P2120/2122/2123/2125/2127/2128/2138)
G02661860Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:

When any of these DTCs are set, check the APP sensor voltage by selecting the following menu items on a hand-held tester: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/ACCEL POS #1 and ACCEL POS #2. If using an OBD II scan tool, refer to the instruction manual.

ACCELERATOR PEDAL POSITION AND SENSOR VOLTAGE SPECIFICATIONS

Trouble Areas ACCEL POS #1 When AP Released ACCEL POS #2 When AP Released ACCEL POS #1 When AP Depressed ACCEL POS #2 When AP Depressed
VCP circuit open Between 0V and 0.2V Between 0V and 0.2V Between 0V and 0.2V Between 0V and 0.2 V
Open or ground short in VPA circuit Between 0V and 0.2V Between 1.2V and 2.0V Between 0V and 0.2V Between 3.4V and 5.0V
Open or ground short in VPA2 circuit Between 0.5V and 1.1V Between 0V and 0.2V Between 2.6V and 4.5V Between 0V and 0.2 V
EPA circuit open Between 4.5V and 5.0V Between 4.5V and 5.0V Between 4.5V and 5.0V Between 4.5V and 5.0V
Normal condition Between 0.5V and 1.1V Between 1.2V and 2.0V Between 2.6V and 4.5V Between 3.4V and 5.0V

HINT: