P26B8
Engine Coolant Bypass Valve C Control Circuit Low
Voltage on the third coolant bypass valve control line is below the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to groundCommon
- Internal short in solenoid coilPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Coolant Bypass Valve C
- Solenoid
- Wiring Harness
P26B8 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.