DTC P2121: Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance: 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.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2121 | Difference between VPA and VPA2 less than 0.4 V, or more than 1.2 V for 0.5 seconds (1 trip detection logic) |
|
HINT:
When any of these DTCs are set, check the APP sensor voltage by entering the following menus on Techstream: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.
| Trouble Areas | Accel Sensor Out No. 1 When AP Released |
Accel Sensor Out No. 2 When AP Released |
Accel Sensor Out No. 1 When AP Depressed |
Accel Sensor Out No. 2 When AP Depressed |
|---|---|---|---|---|
| VCP circuit open | 0 to 0.4 V | 0 to 1.2 V | 0 to 0.4 V | 0 to 1.2 V |
| Open or ground short in VPA circuit | 0 to 0.4 V | 1.2 to 2.0 V | 0 to 0.4 V | 3.4 to 5.0 V |
| Open or ground short in VPA2 circuit | 0.5 to 1.1 V | 0 to 0.2 V | 2.6 to 4.5 V | 0 to 0.2 V |
| EPA circuit open | 4.5 to 5.0 V | 4.5 to 5.0 V | 4.5 to 5.0 V | 4.5 to 5.0 V |
| Normal condition | 0.5 to 1.1 V | 1.2 to 2.0 V | 2.6 to 4.5 V | 3.4 to 5.0 V |
HINT:
- Accelerator pedal positions are expressed as voltages.
- AP denotes for Accelerator Pedal.