Where is bank 1 sensor 1 of2003 Toyota Sequoia?

Bank 1 Sensor 1 of a 2003 Toyota Sequoia is located on the exhaust system, specifically on the exhaust manifold or just after it, before the catalytic converter. This sensor is part of the vehicle's oxygen sensor system, which monitors the air-fuel mixture for optimal engine performance. To access it, you may need to lift the vehicle and work from underneath or remove any components obstructing the sensor.