Cruise Control Multi-Function Input Circuit Malfunction
The P0564 code indicates a problem with the cruise control multi-function input circuit, which includes the steering wheel switches (ON/OFF, SET/COAST, RES/ACCEL, CANCEL) and their wiring. The Powertrain Control Module (PCM) detects an invalid or missing signal from these switches, often due to a short, open circuit, or faulty switch assembly. This prevents the cruise control system from engaging or operating correctly.
1. Most Common Causes
- Faulty or worn cruise control switches
- Corroded, loose, or damaged wiring or connectors in the 'A' input circuit
- Short to ground or voltage in the cruise control harness
- Defective clockspring or steering wheel switch module
- Internal failure in the cruise control module or ECM
- Excessive resistance in signal circuit connections
2. Symptoms You Will Notice
- Cruise control inoperative
- Cruise control light on dash stays on or flashes
- Cruise control engages but cannot be adjusted or canceled
- No response from steering wheel cruise buttons
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to read the code and check for additional codes.
Step 2: Inspect the cruise control switch assembly for physical damage or sticking buttons.
Step 3: Test the switch circuit voltage and resistance at the PCM connector using a multimeter.
Step 4: Check the clock spring for continuity and proper operation.
Step 5: Repair or replace any damaged wiring, connectors, or components as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, the vehicle is safe to drive, but cruise control will not function. The issue does not affect braking or steering.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and repair, but could be higher if the clock spring or switch assembly needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.