P0578
Cruise Control Multi-Function Input "A" Circuit Stuck
- Severity
- High
- Driving
- Drivable — book it in
The cruise control multi-function input "A" is stuck - the module sees a command being held continuously. Depending on which command is stuck, cruise control may refuse to engage, may engage on its own, or may not respond to the cancel command.
Possible causes
- CommonFailed cruise control switch or stalk
- CommonWiring fault in the steering column or console
- CommonDamaged clock spring, on steering-wheel-mounted controls
- CommonCorroded or disturbed connector
- PossibleBrake or clutch switch fault preventing cruise from engaging
- RareFailed control module input
What you might notice
- Cruise control will not engage
- Cruise control cancelling on its own
- Set, resume or cancel not responding
- Cruise warning message
- Check engine light on
What to check, in order
- Know how to cancel cruise control by other means before driving: pressing the brake pedal, pressing the clutch, selecting neutral, or switching the ignition to accessory will all disengage it. Several independent ways exist precisely for this situation.
- Watch the input state with nothing being pressed. A reading that already shows a command active identifies a stuck switch immediately.
- Watch the cruise control switch states on the live data screen while operating each control.
- Check the brake and clutch switches. Cruise control will not engage while the module thinks the brake is pressed, so a brake switch fault presents as a cruise control fault.
- On steering-wheel controls, suspect the clock spring - horn or airbag faults alongside confirm it.
- Inspect the connector if the column or console has been worked on.
- Confirm ordinary driving is unaffected, in which case this can wait.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Vehicle speed control, idle control and auxiliary inputs
P0500P0501P0502P0503P0504P0505P0506P0507P0508P0509P0510P0511P0512P0513P0514P0515P0516P0517P0518P0519P0520P0521P0522P0523P0524P0525P0526P0527P0528P0529P0530P0531P0532P0533P0534P0535P0536P0537P0538P0539P0540P0541P0542P0543P0544P0545P0546P0547P0548P0549P0550P0551P0552P0553P0554P0555P0556P0557P0558P0559P0560P0561P0562P0563P0564P0565P0566P0567P0568P0569P0570P0571P0572P0573P0574P0575P0576P0577P0578P0579P0580P0581P0582P0583P0584P0585P0586P0587P0588P0589P0590P0591P0592P0593P0594P0595P0596P0597P0598P0599