C05AC

What it means

Brake blending separation valve stuck closed — regen and hydraulic circuits cannot be isolated.

Is it safe to drive?

This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.

Most likely causes

• Valve stuck closed

  high

  One of the most commonly reported causes for this code — check this first.

• Carbon or debris buildup preventing free movement

  low

  Less common, but worth ruling out after the more likely causes.

• Component wear with age - mechanical play

  low

  Less common, but worth ruling out after the more likely causes.

Related help

• Full C05AC diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?