P1563

What it means

P1563 on a Cadillac means the cruise control system saw too large a difference between the actual vehicle speed and the speed the driver set. The control unit expects the car to hold the set speed closely, so it logs the fault when the gap stays too high and the system cannot correct it. The exact enable conditions and thresholds vary by model and engine, so check the manufacturer data for the vehicle in question.

Symptoms

• Cruise control cancels itself or will not hold the set speed
• Cruise control will not engage at all
• Vehicle speed drifts well above or below the set speed on hills
• Cruise indicator flashes or is unavailable on the dash
• Check engine light on
• Possible erratic speedometer reading

Possible causes

• Faulty or unreliable vehicle speed signal (speed sensor, wiring or connector)likely
• Throttle control fault or sticking throttle body preventing the system from reaching the requested speedlikely
• Faulty brake pedal switch or cruise cancel switch giving false signalspossible
• Damaged wiring, poor earth or corroded connectors in the cruise control or throttle circuitspossible
• Cruise control switch or steering wheel control faultpossible
• Engine or transmission problem stopping the car holding speed, such as misfire or slipping or poorly shifting gearboxpossible
• Outdated or faulty control module software or internal module faultrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting road speed, set speed and throttle position when the code set
2. Check for other speed sensor, throttle, brake switch or transmission codes and deal with those first
3. Compare the speedometer reading with a known accurate speed, such as a GPS reading, to check the speed signal
4. Inspect the wiring and connectors for the speed sensor, throttle body, brake switch and cruise switches for damage, corrosion or water ingress
5. Check the brake pedal switch operation and that its signal changes correctly on a scan tool live data display
6. Check the cruise switch signals in live data and test the switch operation in each position
7. Check throttle body operation and throttle position readings for smooth, correct movement, cleaning or testing as the model procedure allows
8. Road test with live data to see whether the set speed and actual speed diverge, and whether any engine or gearbox fault is involved

How to fix

• Repair or replace the faulty vehicle speed sensor or its wiring and connectors
• Clean or replace the throttle body or repair its control circuit as testing shows
• Replace a faulty brake pedal switch or cruise control switch
• Repair damaged wiring, earths or corroded connectors
• Fix any underlying engine or transmission fault that prevents speed being held
• Update the control module software if the manufacturer lists it as a known cause, or replace the module only after all other causes are ruled out

Can I keep driving?

This code for other makes

• P1563BuickCruise Vehicle Speed/Set Speed Difference Too High
• P1563ChevroletCruise Vehicle Speed Set Speed Difference Too High
• P1563ChryslerCruise Vehicle Speed Set Speed Difference Too High
• P1563GMCruise Vehicle Speed Set Speed Difference Too High
• P1563GMCCruise Vehicle Speed Set Speed Difference Too High
• P1563OldsmobileCruise Vehicle Speed Set Speed Difference Too High
• P1563SaturnCruise Vehicle Speed Set Speed Difference Too High
• P1563VolkswagenQuantity Adjuster Lower Limit Attained

Nearby codes

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