Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnosis & Repair
Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. After confirming DTC P2121, use the hand-held tester or the OBD II scan tool to confirm the accelerator pedal position sensor output voltage. See Figure.
For diagnosis and repair with Toyota Hand-held tester or an Enhanced OBD II scan tool, see Fig 1. For diagnosis and repair with generic OBD II scan tool (Non Enhanced), see Fig 2.
For APP sensor wiring diagram, see Figure. For ECM location, see Figure. For ECM connector view, see Figure. For testing of systems or components, see BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article or SYSTEM & COMPONENT TESTING - V6 & V8 article. For removal and installation of components, see REMOVAL & INSTALLATION - V6 & V8 article.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.