P26B2Engine Coolant Bypass Valve B Stuck Closed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P26B2 is the closed-stuck counterpart for valve B: the controller expects coolant to flow through the valve but sees no sign of it. No manufacturer documents P26B2 in public sources. Porsche's handling of the valve A code P26B1 on its E-Hybrids illustrates the method: the thermal management unit judges the valve from the temperature difference between two coolant sensors, so a borderline reading can trip the code even with a healthy valve. CARB requires a functional check of such outputs where feasible. If valve B serves an auxiliary circuit such as a transmission oil cooler, as at Ford, a closed valve can let that component run hot; possible causes are a seized valve, a failed actuator, a blocked line or calibration issues.
- What you may notice
- Check engine light
- Rising temperature of the component served by the valve
- Possible temperature warning under heavy load
- Likely causes
- LikelyValve seized in the closed position
- PossibleFailed actuator motor or broken coupling
- RareBlocked or kinked coolant line downstream of the valve
- RareControl software misjudging valve state
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.