How do you refill freon in a 1999 sienna?

To refill the freon in a 1999 Toyota Sienna, first locate the low-pressure service port, usually found on the larger diameter aluminum line. Ensure the engine is off, then connect the refrigerant can to the port. Start the engine and turn the AC to the maximum setting while slowly releasing the refrigerant into the system until it reaches the recommended pressure. Always wear safety gear and consult your vehicle’s manual for specific instructions and precautions.