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.
DTC P2128: Accelerator Position Sensor 2 Signal Circuit-High Input: General Description
The Electronic Throttle Control (ETC) system consists of the throttle body, Throttle Position Sensor (TPS) 1&2 and Accelerator Position Sensor (APS) 1&2. The PCM controls the throttle motor to open and close the throttle valve. The TPS provides feedback to the PCM to control the throttle motor valve opening in response to the driver's demands. The APS is mounted on the accelerator pedal assembly. It has 2 sensors to detect the accelerator position. The PCM uses the signals from APS 1 & 2, and controls the throttle motor based on these signals.
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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.