Cruise Control Multi-Function Input Circuit Stuck
The P0578 code indicates that the powertrain control module (PCM) has detected a stuck signal from the cruise control multi-function input circuit. This circuit includes the steering wheel controls for set, resume, cancel, and coast. The PCM monitors the voltage or resistance from these switches; when the signal remains constant for an extended period (e.g., a button pressed too long or a short circuit), it sets this code. Common causes include a faulty cruise control switch, wiring issues, or a defective clock spring.
01. Most Common Causes
- Faulty cruise control multi-function switch
- Damaged clock spring in steering column
- Short or open in cruise control wiring
- Corroded or loose connector at switch or PCM
02. Symptoms You Will Notice
- Cruise control inoperative
- Cruise control light on dash stays on or flashes
- Cruise control engages without driver input
- Cruise control cannot be set or canceled
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for other related codes.
Step 2: Inspect the cruise control switch and clock spring for physical damage or sticking.
Step 3: Test the switch resistance values with a multimeter and compare to specifications.
Step 4: Check wiring and connectors for shorts, opens, or corrosion between switch and PCM.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but cruise control will not function. If the cruise control engages unexpectedly, it could be a safety concern; otherwise, driving is safe.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and switch replacement. Clock spring replacement can cost $200-$400.