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U3561: Cathode Bypass Valve Control Circuit

Severity
Medium
System
Vehicle Systems
Last reviewed: Last updated:

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does U3561 Mean?

U3561 is a diagnostic trouble code indicating: Cathode Bypass Valve Control Circuit. This code relates to the vehicle systems system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of U3561

Common Causes

Frequently Asked Questions

What does U3561 mean?
U3561 indicates: Cathode Bypass Valve Control Circuit. The vehicle's computer has detected that the Cathode Bypass Valve is not operating within its expected parameters and stored this diagnostic trouble code.
Can I drive with code U3561?
You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with U3561 for extended periods may cause additional problems.
How much does it cost to fix U3561?
Repair costs for U3561 typically range from $80 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

  • 🔧 Inspect and repair Cathode Bypass Valve wiring and connectors
  • 🔧 Replace faulty Cathode Bypass Valve
  1. 1
    Find your vehicle above

    Click your make and model for real owner reports and common causes specific to your vehicle.

  2. 2
    Check for recalls

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.

  3. 3
    Get a professional diagnosis

    A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

Related Codes

U3500 Control Module Input Power A Circuit Range/Performance U3501 Control Module Input Power A Circuit Low U3502 Control Module Input Power A Circuit High U3503 Control Module Input Power A Circuit Intermittent/Erratic U3504 Control Module Input Power B Circuit Range/Performance U3505 Control Module Input Power B Circuit Low U3506 Control Module Input Power B Circuit High U3507 Control Module Input Power B Circuit Intermittent/Erratic U3508 Control Module Input Power C Circuit Range/Performance U3509 Control Module Input Power C Circuit Low