OBD-II code · Powertrain (generic, extended)

P26BA Engine Coolant Bypass Valve C Stuck/Open

The third coolant bypass valve is stuck open.

Is it safe to drive with P26BA?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyValve seized open by sediment
  • PossibleBroken return spring

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.5–2.5 h
Emissions test
Usually unaffected
Parts involved
Coolant Bypass Valve C, Thermostat Housing

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.