OBD-II code · Powertrain (generic, extended)

P26BB Engine Coolant Bypass Valve C Range/Performance

The third coolant bypass valve responds to commands but the resulting coolant temperature behaviour is not as expected.

Is it safe to drive with P26BB?

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

Common causes

  • Most likelyValve partially stuck by sediment
  • PossibleWeak return spring fails to close fully
  • Less likelySensor element aged beyond calibration window

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
1–3.5 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.