P1563
Cruise Vehicle Speed Set Speed Difference Too High.
- GM
- Powertrain
- Manufacturer code
- Low severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 5
- AreaVehicle speed, idle control and auxiliary inputs
- 63
- FaultThe specific fault in that area
What it means
On GM vehicles, P1563 means 'Cruise Vehicle Speed Set Speed Difference Too High'. The control unit saw the actual road speed differ from the speed set on the cruise control by more than it expects while cruise was active, so it could not hold or reach the set speed properly. The cause depends on how cruise is controlled on the model, either by throttle actuator or by a separate cruise module.
Symptoms
- Cruise control will not hold the set speed or keeps dropping out
- Vehicle speed surges or hunts above and below the set speed
- Cruise control cancels itself unexpectedly
- Cruise control will not engage at all
- Malfunction indicator lamp or service lamp on in some cases
Possible causes
- Faulty or inaccurate vehicle speed signal, such as a failing speed sensor or wheel speed sensor inputlikely
- Wiring or connector faults in the speed sensor or cruise control circuits (chafing, corrosion, poor pin tension)likely
- Throttle control fault, such as a sticking or dirty throttle body or faulty throttle actuator, so the set speed cannot be followedpossible
- Faulty cruise control switch, brake switch or clutch switch giving erratic cancel or resume signalspossible
- Vacuum-operated cruise servo or its hoses leaking or failing, on models that use onepossible
- Fault in the engine control module or cruise control module, or an outdated calibration where the manufacturer has issued an updaterare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting road speed, throttle position and engine load when the code set
- Look for other speed sensor, throttle or brake switch codes and deal with those first
- Compare the displayed vehicle speed on a scan tool with the speedometer and a known true speed such as a GPS reading
- Inspect the wiring and connectors for the speed sensor, throttle body, cruise switch and brake and clutch switches for damage, corrosion or looseness
- Check the brake and clutch switch operation and the cruise switch signals in live data while pressing the controls
- Inspect the throttle body for carbon build-up and check smooth throttle movement and plausible position readings
- On models with a vacuum servo, inspect the hoses and servo for leaks and correct operation
- Check for applicable software updates and technical bulletins for the specific model and engine
How to fix
- Repair or replace the faulty speed sensor or repair its wiring and connectors
- Replace worn or faulty brake, clutch or cruise control switches
- Clean or replace the throttle body or actuator if it is sticking or giving implausible readings
- Replace leaking vacuum hoses or a faulty cruise servo where fitted
- Apply a manufacturer calibration update only if an outdated calibration is confirmed as the cause for that model
- Replace the control module only after all inputs, supplies and wiring are proven good
Can I keep driving?
Low severity
The car is normally safe to drive, but cruise control may be unreliable, so use the pedal to control speed and book it in for diagnosis. If the car surges or the throttle behaves oddly, have it checked sooner.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.
This code for other makes
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- P1563GMCCruise Vehicle Speed Set Speed Difference Too High
- P1563OldsmobileCruise Vehicle Speed Set Speed Difference Too High
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