OBD Guide

U063C

Lost Communication With Coolant Bypass Valve Actuator B

U063C is an OBD-II diagnostic trouble code meaning: Lost Communication With Coolant Bypass Valve Actuator B. Common causes: open or short circuit in valve circuit, coolant bypass valve malfunction. Estimated repair cost: $17–67.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–67 (est.)

Symptoms

  • Check Engine Light Is On
  • Unstable engine operation
  • Increased engine temperature
  • Reduced cooling system efficiency
  • Errors in climate control operation

Causes

  • Open or short circuit in valve circuit
  • Coolant bypass valve malfunction
  • Connector problems or contact corrosion
  • Engine ECU malfunction
  • Wiring Harness Problems

How to Fix

  1. Check valve control circuit integrity
  2. Inspect connectors and contacts for damage
  3. Check valve resistance and operation
  4. Scan the ECU for additional errors
  5. Replace the coolant bypass valve if necessary.

Related codes

Error U063C by Vehicle Brand

FAQ

What does the U063C code mean?

U063C is an OBD-II diagnostic trouble code that indicates: Lost Communication With Coolant Bypass Valve Actuator B

What causes a U063C error code?

The most common causes of U063C include: Open or short circuit in valve circuit; Coolant bypass valve malfunction; Connector problems or contact corrosion; Engine ECU malfunction.

How do I fix a U063C diagnostic trouble code?

To fix U063C: Check valve control circuit integrity. Inspect connectors and contacts for damage. Check valve resistance and operation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U063C?

Limited driving only, diagnose soon

How much does it cost to fix U063C?

The estimated repair cost for U063C is $17–67. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat