P26BD: Cabin-heating valve D has its own output-circuit monitor

P26BD concerns the control-circuit/open classification for coolant bypass valve D. Ford defines D in this section as the engine-coolant cabin-heating bypass valve. This identification separates it from the radiator and automatic-transmission coolant valves described nearby.

Heat delivery is not the electrical threshold

The documented detailed representation is P26BD_13. A smart driver reports the output-circuit fault, with continuous monitoring and a five-second duration. The code therefore supplies electrical control evidence rather than a measured cabin-temperature or coolant-flow result.

A lack of cabin heat may be useful operating context, but it does not prove which electrical path caused the report. Conversely, acceptable heat at one moment cannot demonstrate that an intermittent circuit event never occurred.

Distinguish open from the paired high condition

The same section lists P26BF/P26BD_12 for a short-to-battery classification. Preserve that distinction and the complete scanner identifier rather than treating both descriptions as interchangeable valve failures.

Useful verification first confirms the cabin-heating valve’s location and function on the actual vehicle, then relates command state to the driver’s reported condition. The summary does not provide a connector pin, resistance value or permission to apply power directly to the valve. It also does not establish a mechanically stuck valve or require replacing a heater assembly. Those conclusions need the vehicle-specific circuit and functional procedure.

Source and applicability

Ford 2024–2025 gasoline OBD summary, July 16, 2024 revision; only the described monitor and architecture. Model, engine and calibration fitment are not inferred. The monitor explanation does not identify a failed part or replace the applicable service procedure. Ford PDF, page 143.