Circuit/System Description

WARNING: This page is about a different variant/trim than selected.

For an overview of the component/system, refer to : Exhaust Aftertreatment System Description

Circuit	Description
Control	The output circuit varies between ground and 12 V. The motor is bidirectional.
Low Reference	Grounded through the control module.

Component	Description
A38 Reductant Pump and Sensor Assembly	The supply pump and the backflow pump are combined in the reductant pump module, which is part of the reductant fluid reservoir assembly. Both pumps are designed as vibration pumps. In this type of pump a solenoid attracts a piston against the force of a spring. At the same time, the piston sucks in fluid through an inlet check-valve. When the current through the solenoid is turned off, the spring pushes the piston forward and the fluid is pushed through an outlet check-valve. The frequency in which the solenoid is turned on/off determines how much fluid is conveyed.
K20 Engine Control Module	The control module contains a microprocessor used to process input data to control outputs. The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.

Component

Description

A38 Reductant Pump and Sensor Assembly

The supply pump and the backflow pump are combined in the reductant pump module, which is part of the reductant fluid reservoir assembly. Both pumps are designed as vibration pumps. In this type of pump a solenoid attracts a piston against the force of a spring. At the same time, the piston sucks in fluid through an inlet check-valve. When the current through the solenoid is turned off, the spring pushes the piston forward and the fluid is pushed through an outlet check-valve. The frequency in which the solenoid is turned on/off determines how much fluid is conveyed.

K20 Engine Control Module

The control module contains a microprocessor used to process input data to control outputs.
The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.