P26B2
Engine Coolant Bypass Valve B Stuck Closed
The second coolant bypass valve is stuck closed.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Valve seized closed by debrisCommon
- Actuator linkage jammed in closed positionPossible
- Carbon or debris buildup preventing free movementLess likely
Parts involved
- Coolant Bypass Valve B
- Thermostat Housing
P26B2 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.