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.
Circuit/System Description
The throttle actuator control (TAC) system uses two accelerator pedal position (APP) sensors to monitor the accelerator pedal position. The APP sensors 1 and 2 are located within the pedal assembly. Each sensor has the following circuits:
- A 5-volt reference circuit
- A low reference circuit
- A signal circuit
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to pedal movement. Both processors monitor each other's data to verify that the indicated APP calculation is correct.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.