The Bosch DEF Pump - 0928404001 is a diesel exhaust fluid pump designed for use in vehicles with selective catalytic reduction (SCR) systems. It is responsible for delivering the precise amount of DEF (a mixture of urea and water) to the exhaust stream, which helps reduce harmful emissions. The pump is compact and durable, with a flow rate of up to 10 liters per minute. It is compatible with a variety of DEF tank sizes and can be easily integrated into existing vehicle systems. The Bosch DEF Pump - 0928404001 is a reliable and efficient solution for meeting emissions standards and improving overall vehicle performance.