LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2009 >> Tundra Base, 4.0 U >> Repair and Diagnosis >> External Pages >> Different car >> Section 249 (Engine Control System (2TR-FE)) >> SFI System >> DTC P2121 Throttle/Pedal Position Sensor/Switch "D" Circuit Range/Performance >> Monitor Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Monitor Description

WARNING: This page is about a different car, the 2009 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the voltage outputs of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal position sensor is malfunctioning. The ECM turns on the MIL and the DTC is set.