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.
Normal Operation
The speed control actuator sends a voltage reference signal through circuit 511 (LG). The stoplamps provide a ground path that enables speed control operation. When the brake pedal is applied, the voltage goes high and speed control goes into stand-by mode.
Voltage for the speed control servo clutch (internal to the speed control actuator) is supplied by the smart junction box (SJB) to the speed control deactivator switch through circuit 1928 (RD/WH). The speed control deactivator switch (closed when the brake pedal is not applied) then routes the voltage to circuit 248 (TN/OG) to the speed control actuator. When the brake pedal is firmly pressed, the speed control deactivator switch opens and voltage is no longer supplied to the speed control servo clutch.
Possible Causes
- Circuit 248 (TN/OG) shorted to voltage
- Circuit 511 (LG) open
- Obstructions to the accelerator pedal or linkage
- Speed control deactivator switch
- Stoplamp switch
- Speed control cable
- Accelerator cable
- Speed control actuator
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.