Mismatched tire sizes or incorrect tire pressure causing actual road speed to differ from what the speed sensors report; A failing vehicle speed sensor (VSS) or wheel speed sensor sending an erratic signal to the cruise module; Wiring damage or corrosion in the cruise control switch circuit, including the stalk or steering wheel buttons; A sticking or misadjusted cruise control cable or actuator on cable-driven systems; Brake pedal position switch out of adjustment or intermittently sticking, causing the cruise module to see conflicting brake and speed data; Engine performance faults such as a vacuum leak or throttle body carbon buildup that prevent the engine from maintaining speed under cruise load; A faulty cruise control module or body control module (BCM) that misinterprets valid speed inputs

DTC codes / GM codes / P1563

P1563 · GMCruise Vehicle Speed Set Speed Difference Too High

Q: What does code P1563 mean?

Cruise Vehicle Speed Set Speed Difference Too High. P1563 on a GM vehicle means the cruise control module has detected that the actual vehicle speed differs from the set speed by more than the calibrated threshold for a sustained period. The computer is not reporting a sensor failure; it is flagging a mismatch between what you asked the cruise system to hold and what the vehicle is actually doing.

P1563 on a GM vehicle means the cruise control module has detected that the actual vehicle speed differs from the set speed by more than the calibrated threshold for a sustained period. The computer is not reporting a sensor failure; it is flagging a mismatch between what you asked the cruise system to hold and what the vehicle is actually doing.

SystemPowertrain

Code typeGM specific

SeverityLow

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Cruise control disengages or refuses to engage shortly after you set a speed
The cruise indicator lamp flashes or stays off when you press the set button
Vehicle speed drifts noticeably above or below the set speed on grades
The engine may surge or hesitate while cruise is active as the system tries to correct speed
Often no symptoms besides the warning light, especially if the fault is intermittent
Reduced fuel economy on long highway trips because the system cannot hold a steady speed

Common causes, most likely first

Mismatched tire sizes or incorrect tire pressure causing actual road speed to differ from what the speed sensors report
A failing vehicle speed sensor (VSS) or wheel speed sensor sending an erratic signal to the cruise module
Wiring damage or corrosion in the cruise control switch circuit, including the stalk or steering wheel buttons
A sticking or misadjusted cruise control cable or actuator on cable-driven systems
Brake pedal position switch out of adjustment or intermittently sticking, causing the cruise module to see conflicting brake and speed data
Engine performance faults such as a vacuum leak or throttle body carbon buildup that prevent the engine from maintaining speed under cruise load
A faulty cruise control module or body control module (BCM) that misinterprets valid speed inputs

How to diagnose and fix it

Verify all four tires are the same size and inflated to the door-jamb specification, then clear the code and road-test the cruise system
Use a scan tool to compare vehicle speed reported by the engine control module (ECM), the transmission, and the antilock brake system (ABS) module while driving
Inspect the cruise control switch circuit for chafed wires, corroded connectors, and correct resistance values at the stalk or steering wheel buttons
Check the brake pedal position switch adjustment and confirm it releases cleanly without dragging
On cable-actuated systems, inspect the cruise cable for binding, correct routing, and proper adjustment at the throttle body
Perform a throttle body cleaning and check for vacuum leaks if the engine cannot hold speed under cruise load
If all inputs and mechanical components test good, follow the factory diagnostic flow for the cruise control module before replacing it

What the speed difference code really flags

A common miss is uneven tire wear or a mismatched spare tire that changes the rolling circumference enough to trip P1563 without any failed component.
The code can set from a brake pedal switch that is slightly out of adjustment, because the cruise module sees brake input and speed input that do not agree during a set-speed event.
P1563 does not always mean the cruise module is bad; engine performance faults that prevent the vehicle from holding speed under load will set it just as readily.
On some GM platforms the cruise control function is integrated into the body control module, so a BCM communication or voltage issue can produce this code without a dedicated cruise module fault.
After any repair, the cruise system often needs a relearn or calibration drive cycle before the module will accept a new set speed without resetting the code.

Can I keep driving with P1563?

The vehicle remains safe to drive because P1563 affects only the cruise control function and does not impair braking, steering, or engine power. Avoid using cruise control until the fault is repaired, especially in traffic or on slippery roads where an unexpected disengagement could be distracting.

Tools that help

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Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.