P0578
Cruise Control Multi-Function Input A Circuit Stuck
Cruise control
Generic OBD-II
Low
What it means
P0578 means the ECM sees the cruise control multi-function input 'A' as stuck — a button or switch contact that reads as continuously active. It usually points to the cruise switch or its wiring. Cruise control won't operate, but the rest of the vehicle is unaffected and safe to drive.
Low
Can I keep driving? Safe to drive — only the cruise control is affected; engine, brakes, and steering are unchanged.
Common symptoms
What you'll notice
- Cruise control does not function
- Cruise control indicator light on the dash
- Check-engine light on
- Unable to set or hold a steady speed with cruise
Common causes
Most likely first
- Faulty cruise control multi-function switch (stuck input)Likely
- Damaged or shorted wiring in the cruise control circuitCommon
- Loose or corroded connections in the cruise control circuitCommon
- Failed brake pedal position switchLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check whether a cruise button reads as constantly pressed.
- Test the multi-function (cruise) switch for a stuck or shorted contact.
- Inspect the wiring and connectors for shorts, opens, or corrosion.
- Check the brake pedal position switch, which can interrupt cruise operation.
- Repair or replace the faulty switch or wiring, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0578?+
Yes. The fault is limited to the cruise control system. You can drive normally, but cruise control won't work until the stuck input is repaired.
Can I just clear P0578?+
It will come back while a switch contact stays stuck or a wire is shorted. Repair the circuit to clear it permanently.
Related codes
Often seen with P0578
Read & clear P0578 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX