Cruise Control Multi-Function Input Circuit Range/Performance
The P0579 code indicates that the Powertrain Control Module (PCM) has detected an abnormal voltage signal from the cruise control multi-function switch circuit. This switch typically integrates functions like SET, RESUME, CANCEL, and ON/OFF. The circuit range/performance issue means the signal is outside expected parameters, often due to a faulty switch, wiring problems, or a poor ground connection.
01. Most Common Causes
- Faulty cruise control multi-function switch
- Damaged or corroded wiring/connectors in the switch circuit
- Poor ground connection
- Faulty PCM (rare)
02. Symptoms You Will Notice
- Cruise control inoperative or intermittent
- Cruise control light on dash may flash or stay on
- Engine light illuminated
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0579 and check for other codes.
Step 2: Visually inspect the cruise control switch and wiring for damage or corrosion.
Step 3: Test the switch resistance and voltage signals per manufacturer specs.
Step 4: Check ground connections and repair as needed.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but cruise control will not work. The vehicle's braking and acceleration are unaffected.
How much does it cost to fix?▼
Typically $50-$150 for switch replacement and labor. Diagnostic fees may add $50-$100.