P0566 is an OBD-II trouble code that points to a problem in the cruise control “set” signal circuit. In plain English, your car’s computer is not happy with the electrical signal it gets when you try to set or resume cruise control. While this code usually doesn’t leave you stranded, it can disable cruise control and may hint at wiring or switch issues that get worse over time. In this guide, you’ll learn what P0566 means, common causes, symptoms, how to diagnose it, and what repairs typically cost.
What Does P0566 Mean?
P0566 stands for “Cruise Control Set Signal Malfunction.” Your engine control module (ECM) or powertrain control module (PCM) expects a specific voltage or signal when you press the cruise control “SET” or “RESUME” button. If that signal is missing, out of range, shorted, or stuck on, the PCM stores P0566 and usually disables cruise control for safety.
This is an electrical or logic fault, not a mechanical engine problem. It’s typically related to the steering wheel switch, clockspring, wiring, or in some cases the PCM itself. The car will usually drive normally otherwise.
Quick Reference
- Code: P0566 – Cruise Control Set Signal Malfunction
- Severity: Low to moderate (comfort/safety feature issue)
- Typical Symptoms: Cruise control inoperative or intermittent
- Most Common Causes: Faulty cruise switch, clockspring, wiring fault
- Primary Fixes: Switch or clockspring replacement, wiring repair
Real-World Example / Field Notes
In the shop, P0566 often shows up on cars where the owner says, “Cruise works sometimes, then just shuts off.” One common pattern: the cruise control light comes on when you hit the button, but it won’t actually set speed, or it drops out when you move the steering wheel slightly. On several vehicles, I’ve traced this to a worn steering wheel clockspring or a failing cruise switch assembly. In other cases, a soda spilled on the steering wheel controls caused sticky buttons and shorted circuits that triggered P0566.
Symptoms of P0566
- Cruise control inoperative – Cruise will not set or resume at any speed.
- Intermittent cruise operation – Works sometimes, drops out randomly or with steering movement.
- Cruise light but no set – The dash cruise indicator turns on, but speed will not engage.
- Unexpected cruise cancel – Cruise kicks off without touching the brake or cancel switch.
- Multiple steering wheel button issues – Other buttons on the wheel (audio, horn, etc.) may act up if the clockspring is failing.
- Stored cruise-related codes – P0566 may appear with other cruise or brake switch codes.
- No drivability change – Engine power and shifting usually feel normal; only the cruise feature is affected.
Common Causes of P0566
Most Common Causes
- Faulty cruise control switch – Worn or contaminated “SET/RESUME” buttons can send incorrect or no signal.
- Defective clockspring – The ribbon cable inside the steering wheel hub can break, causing intermittent or lost signals.
- Wiring harness issues – Broken, chafed, or corroded wires between the switch, clockspring, and PCM.
- Poor electrical connections – Loose connectors or oxidized terminals at the steering wheel, clockspring, or PCM.
- Incorrect aftermarket steering wheel / modifications – Swapped wheels or added accessories can disturb the cruise wiring.
Less Common Causes
- Faulty brake pedal switch – If the PCM “thinks” the brakes are applied all the time, it may flag P0566 and disable cruise.
- Faulty clutch switch (manual transmission) – Similar to the brake switch; a stuck clutch switch can cancel cruise.
- PCM/ECM internal fault – Rare, but a failed input circuit inside the control module can misread the set signal.
- Blown fuse or power supply issue – Loss of power to the cruise control circuit can trigger related codes.
- Water intrusion or prior collision damage – Corrosion in connectors or damaged harnesses from past repairs.
Diagnosis: Step-by-Step Guide
To properly diagnose P0566, you’ll want a basic scan tool (ideally one that can view live data), a digital multimeter, and access to wiring diagrams for your specific vehicle. A test light and back-probing pins can also be helpful. If you’re comfortable with steering wheel and airbag components, you can do much of this yourself; if not, leave clockspring work to a pro for safety.
- Confirm the code and record data
Connect a scan tool, confirm P0566 is present, and note any other related codes (brake switch, cruise, or communication codes). Save freeze-frame data to see under what conditions the fault set. - Check basic cruise operation
With the engine running and vehicle safely on the road, attempt to turn on cruise and press “SET.” Note whether the cruise light comes on, if speed sets, and if it drops out when you move the steering wheel or hit bumps. - Inspect fuses and obvious wiring
Check the owner’s manual or wiring diagram for cruise-related fuses. Inspect visible wiring under the dash and around the steering column for rubbing, tape repairs, or aftermarket splices. - Test steering wheel buttons
Many scan tools allow you to see cruise switch status in live data (ON, SET, RESUME, CANCEL). While watching the data, press each button. If the PCM never sees the “SET” command or it flickers, suspect the switch or clockspring. - Check clockspring condition
If the horn, airbag light, or other steering wheel controls are also acting up, the clockspring is a prime suspect. Carefully inspect for prior steering wheel work or airbag deployment that could have damaged it. - Test the cruise switch circuit
Using a wiring diagram, back-probe the cruise switch wires at the clockspring or connector. Check for proper reference voltage and changing resistance/voltage when pressing the “SET” button. Compare to factory specs. - Inspect brake and clutch switches
Verify that the brake lights work correctly and that the brake/clutch switch signals change state in scan tool data. A switch stuck “on” can prevent cruise engagement and confuse diagnostics. - Check continuity and shorts to ground
With the battery disconnected, use a multimeter to check continuity of the set signal wire from the switch/clockspring to the PCM. Look for opens, shorts to ground, or shorts to power. - Evaluate PCM input (advanced)
If all external components test good, a professional may use an oscilloscope or advanced scan tool to verify the PCM is correctly seeing the signal. If not, internal PCM failure becomes more likely. - Clear codes and road test
After repairs, clear the code, perform a road test, and attempt to use cruise control in various conditions. Re-scan to confirm P0566 does not return.
Pro tip: If cruise control drops out only when you turn the steering wheel to certain positions, focus on the clockspring and wiring inside the steering column before replacing any switches or modules.
Possible Fixes & Repair Costs
Repairs for P0566 focus on restoring a clean, reliable set signal to the PCM. Costs vary widely depending on which component failed and how difficult it is to access.
- Replace cruise control switch / steering wheel buttons – Parts $50–$200, labor 0.5–1.5 hours.
- Replace clockspring (spiral cable) – Parts $80–$300, labor 1–2.5 hours depending on airbag and trim complexity.
- Repair wiring or connectors – Typically 0.5–2 hours labor; cost depends on location and extent of damage.
- Replace brake or clutch switch – Parts $20–$80, labor 0.3–1 hour.
- PCM/ECM replacement and programming – Rare; parts $400–$1,200+ plus 1–2 hours programming labor.
In most real-world cases, you’re looking at roughly $150–$450 total for diagnosis and repair at a typical shop. Factors that affect cost include vehicle make, airbag/clockspring complexity, shop labor rate, and whether additional wiring repairs are needed.
Can I Still Drive With P0566?
Yes, you can usually continue driving with P0566 without immediate risk to the engine or transmission. The main downside is that your cruise control may not work or may be unreliable. On long trips, that can be tiring and inconvenient. If the underlying issue involves damaged wiring in the steering column, there’s a small risk it could affect other systems over time, such as the horn or airbag, so you shouldn’t ignore it indefinitely.
What Happens If You Ignore P0566?
If you ignore P0566, you’ll likely lose cruise control permanently or have it work only intermittently. Over time, a failing clockspring or deteriorating wiring can spread to other circuits, leading to inoperative horn, airbag warning lights, or additional electrical faults. While it’s not an emergency breakdown code, fixing it early can prevent more expensive steering column or electrical repairs later.
Related Codes
- P0574 – Cruise Control System Vehicle Speed Too High
- P0573 – Brake Switch “A” Circuit High
- P0572 – Brake Switch “A” Circuit Low
- P0571 – Brake Switch “A” Circuit
- P0570 – Cruise Control Accelerate Signal
- P0569 – Cruise Control Coast Signal
- P0568 – Cruise Control Set Signal
- P0567 – Cruise Control Resume Signal
- P0565 – Cruise Control On Signal
- P0564 – Cruise Control Multi-Function Input “A” Circuit
Key Takeaways
- P0566 means the PCM is not seeing a proper cruise control “set” signal.
- The car usually drives fine, but cruise control may not work or may be intermittent.
- Most common culprits are the cruise switch, clockspring, or wiring in the steering column.
- Diagnosis involves checking live data, switch operation, clockspring continuity, and brake/clutch switches.
- Typical repair costs fall in the $150–$450 range, depending on the part and labor.
- It’s generally safe to drive, but you should repair it to avoid further electrical issues.
Vehicles Commonly Affected by P0566
P0566 can show up on many OBD-II equipped vehicles, but it’s especially common on models with steering wheel-mounted cruise controls and complex clocksprings. In the field, I see it frequently on:
- Ford and Lincoln – F-150, Explorer, Fusion, Escape, and similar SUVs and trucks.
- GM (Chevrolet, GMC, Buick) – Silverado/Sierra, Tahoe/Suburban, Malibu, and mid-size SUVs.
- Chrysler, Dodge, Jeep, Ram – Ram pickups, Grand Cherokee, Charger, Caravan, and similar models.
- Honda and Acura – Accord, Civic, CR‑V, and MDX/RDX with steering wheel cruise controls.
- Toyota and Lexus – Camry, Corolla, RAV4, Highlander, and some Lexus sedans and SUVs.
- Hyundai and Kia – Elantra, Sonata, Santa Fe, Sportage, and Sorento.
Any vehicle that uses a clockspring to route cruise control signals through the steering wheel can potentially set P0566 when that component or its wiring starts to fail.
FAQ
Can I clear P0566 and keep driving without fixing it?
You can clear P0566 with a scan tool, and the light may stay off for a while, but if the underlying fault is still there, the code will usually return. Driving is generally safe, but you’ll likely continue to have cruise control issues until the root cause is repaired.
Is P0566 related to the brake light switch?
Indirectly, yes. A faulty brake light switch can keep the PCM thinking the brakes are applied, which disables cruise control and can confuse diagnostics. While P0566 specifically targets the set signal, it’s smart to check brake switch operation and look for codes like P0571 or P0573 at the same time.
Can a bad clockspring cause P0566?
Absolutely. A failing clockspring is one of the most common causes of P0566, especially if the cruise control cuts out when you turn the steering wheel or if the horn and airbag light are acting up. The clockspring carries the cruise switch signals from the steering wheel to the rest of the car.
How do I know if the cruise switch or PCM is bad?
Start by checking live data for the cruise switch. If the PCM never sees the “SET” command when you press the button, test the switch and wiring first. PCM failure is rare and should only be suspected after verifying the switch, clockspring, wiring, and related switches are all good and the signal still doesn’t reach the PCM properly.
Can a low battery or charging problem trigger P0566?
Low system voltage can cause all kinds of odd electrical behavior, but P0566 by itself is usually not caused by a weak battery. However, if you have multiple electrical codes, dim lights, or starting issues, it’s wise to test battery and alternator output before chasing individual circuit faults.