P26B7: coolant bypass valve C motor-control circuit is open

P26B7 is the open-circuit diagnosis for engine coolant bypass valve C control. The cited controller detects an open load when its H-bridge is energized. This concerns the motor-control path rather than the separate position-feedback range checks.

Energized-driver evidence

The actual failure criterion is the driver's open-control-circuit report. The status must be determinate, the diagnostic enabled, run/crank valid and the engine not cranking. The report must be present for four seconds within a five-second window. The entry is Type B, two trips.

A stationary valve by itself does not reproduce this electrical criterion. It could be stationary because movement was not requested, while this monitor specifically requires the energized driver and its open-load feedback.

Useful confirmation

Review the motor command and driver status together, using the exact vehicle's supported data. Keep a missing position message separate from an open motor circuit; the summary assigns those to different diagnostic functions.

After the identified cause is addressed, verify that the energized control-circuit test completes without the open report. Observing a coolant-temperature change or clearing the DTC does not independently establish electrical continuity. The source supplies no resistance limit, connector pinout or proof that the coolant valve assembly must be replaced. Any cooling-system access should follow the applicable procedure for temperature and pressure hazards.

Source and application limits

This explanation covers the cited 2025 GM monitor. Confirm the vehicle and calibration in its service information before applying these limits; inclusion in this file does not establish model compatibility. GM diagnostic parameters, PDF page 844.