Cruise Control Multi-Function Input Circuit High
The P0581 code indicates that the powertrain control module (PCM) has detected a high voltage signal from the cruise control multi-function input circuit. This circuit typically receives signals from the steering wheel controls (set, resume, cancel, etc.). A high voltage condition can be caused by a short to power, a faulty switch, or a wiring issue. This prevents the cruise control system from operating correctly.
1. Most Common Causes
- Short to voltage in the cruise control input 'A' circuit
- Faulty cruise control multifunction switch
- Damaged or shorted wiring in the steering wheel or steering column harness
- Corroded, bent, or poor-contact electrical connectors
- Faulty shunt resistor or switch resistor
- Internal PCM failure (uncommon)
2. Symptoms You Will Notice
- Cruise control inoperative
- Cruise control light on dash may flash or stay on
- Engine Check Light illuminated
3. 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 wiring for damage, corrosion, or shorts.
Step 3: Test the voltage at the cruise control input circuit with a multimeter; should be low when switch is not pressed.
Step 4: If voltage is high, disconnect the switch and recheck; if voltage drops, replace the switch.
Step 5: If voltage remains high, repair the short to power in the wiring harness.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but cruise control will not work. The vehicle remains drivable.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and switch replacement, depending on labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.