What should you check if your brake system warning light stays on after shifting to drive?

The brake system warning light remaining illuminated after shifting into drive typically indicates that there may be an issue with the braking system, often related to the parking brake being engaged. Before proceeding with driving, it is crucial to ensure that the parking brake is fully released. If the light stays on despite the parking brake being disengaged, it could signal a more serious problem with the brake system that needs to be diagnosed.

The other checks, while important for vehicle maintenance and safety, do not directly address the specific concern indicated by the brake system warning light. Ensuring the engine is turned off does not provide relevant information about the brakes. Checking tire inflation is unrelated to the brake warning light, and testing headlights, while necessary for visibility and driving safety, does not pertain to the brake system's status. Thus, confirming that the parking brake is released is the most pertinent action to take in this situation.