P26C0
Engine Coolant Bypass Valve D Stuck/Open
The fourth coolant bypass valve is stuck open.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Valve seized open by sedimentCommon
- Broken return springPossible
Parts involved
- Coolant Bypass Valve D
- Thermostat Housing
P26C0 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.