What causes fault code P0578?

• Most likely: Mechanical failure of the steering wheel buttons (stuck button or internal short) • Likely: Faulty clock spring (spiral cable) causing intermittent shorts or signal bridge • Possible: Damaged wiring harness between the steering column and the control module (chafed wires) • Rare: Corrosion in connectors or internal failure of the Engine Control Module (ECM)

Powertrain (Engine & Gearbox)Standard EOBD

P0578 - Cruise Control Multi-Function Input A Circuit Stuck

Q: What are the symptoms of fault code P0578?

• Cruise control system will not engage • Check Engine Light (MIL) may be illuminated • 'Cruise Control Service Required' message on the dashboard • Other steering wheel functions (e.g., horn or audio controls) might be affected if the clock spring is the culprit

Q: How do you fix fault code P0578?

STEP 1: Physically check the steering wheel buttons for stickiness or travel. Clean with electronic contact cleaner if debris is suspected. STEP 2: Use a scan tool to monitor live data (PIDs) for cruise control switch status. Check if the ECM reports a button as 'Pressed' while idle. STEP 3: Measure the voltage in the circuit at the steering column connector. Reference voltage is typically 5V or 12V. In idle mode, signal voltage should be at a specific baseline. If voltage is stuck between 1.5V and 3.5V without input, a short or faulty switch is likely. STEP 4: Test the clock spring for continuity (Ohms) while rotating the steering wheel. Resistance should remain stable and below 1 Ohm. STEP 5: If wiring and clock spring pass testing, replace the cruise control switch assembly.

Last updated:1 February 2026

Related:Clock Spring, Rattknappar (Cruise Control Switch), ECM/PCM (Engine Control Module), Wiring Harness

System

Powertrain (Engine & Gearbox)

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P0500

Vehicle Speed Sensor (VSS) 'A' Range/Performance

P0501

Vehicle Speed Sensor 'A' Range/Performance

P0502

Vehicle Speed Sensor 'A' Circuit Low Input

P0503

Vehicle Speed Sensor (VSS) Intermittent/Erratic/High

Technical Description

Diagnostic Trouble Code (DTC) P0578 is triggered when the Engine Control Module (ECM) or Powertrain Control Module (PCM) detects that the cruise control multi-function switch 'A' circuit signal is stuck in a specific voltage range for a predetermined amount of time. Most modern cruise control systems use a voltage divider circuit where different buttons produce different voltage drops. If the voltage feedback remains constant at a level that indicates an active button press, but does not transition back to the baseline 'open' voltage, the ECM identifies this as a 'stuck' condition and disables the system for safety.

Possible Causes

Mechanical failure of the steering wheel buttons (stuck button or internal short)

Faulty clock spring (spiral cable) causing intermittent shorts or signal bridge

Damaged wiring harness between the steering column and the control module (chafed wires)

Corrosion in connectors or internal failure of the Engine Control Module (ECM)

Symptoms

Cruise control system will not engage

Check Engine Light (MIL) may be illuminated

'Cruise Control Service Required' message on the dashboard

Other steering wheel functions (e.g., horn or audio controls) might be affected if the clock spring is the culprit

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P0578 - Cruise Control Multi-Function Input A Circuit Stuck

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P0578 - Cruise Control Multi-Function Input A Circuit Stuck

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