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P0568Cruise Control Set Signal

The PCM has detected a fault in the cruise control Set signal, such as the input reading stuck active or out of range.

Definition

The PCM monitors the Set switch input, which stores the current vehicle speed and engages cruise (and typically serves as coast/decelerate). P0568 sets when the Set signal is implausible — stuck active, missing, or at a voltage that matches no valid switch position on the multiplexed circuit. Because a stuck Set input could cause unintended engagement, the PCM disables cruise control while the fault is active. The driver symptom is cruise that will not set or an entirely inoperative system; there is no MIL or driveability effect on most applications.

Common causes

  • Worn or sticking Set/Coast button in the steering wheel switch
  • Out-of-spec resistor in the switch ladder for the Set position
  • Short to ground on the switch signal circuit mimicking a pressed button
  • Worn clockspring interrupting the signal intermittently
  • Corroded terminals in the column or switch connector
  • Faulty PCM input circuit (rare)

Common misdiagnoses

  • PCM or cruise module replaced for a switch fault
  • Brake light switch replaced when the Set circuit is the problem
  • Throttle body or actuator replaced for cruise not engaging
  • Vehicle speed sensor replaced unnecessarily

Troubleshooting steps

  1. 1.Monitor the Set input on a scan tool

    Press Set repeatedly while watching the switch PID; the input must follow the button exactly and never show active on its own.

  2. 2.Test the switch resistance values

    With the switch disconnected, verify the Set position produces the specified resistance and that no button's value drifts into another's range.

  3. 3.Check for a shorted signal circuit

    With the switch unplugged, an input that still reads as pressed indicates a harness short to ground (or voltage, per design) between the column and PCM.

  4. 4.Evaluate the clockspring

    Monitor the input while turning the wheel lock to lock; dropouts tied to wheel angle point to the spiral cable.

  5. 5.Verify engagement after repair

    Road test above the minimum cruise speed (typically about 25 mph) and confirm Set engages, Coast works, and the code stays clear.

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