SCR frame module control unit, component description

W14.40-1195-06

Location

A95 SCR frame module control unit

The SCR frame module control unit (A95) is located at the rear of the vehicle on the inside of the right longitudinal frame member.

Task

The SCR frame module control unit (A95) reads in the analog signals from the connected sensors, converts these into digital CAN (Controller Area Network) signals and transmits them to the engine control (MR) control unit.

The SCR frame module control unit also provides the supply voltage for the connected active sensors and received the signals for actuation of the connected components from the engine control (MR) control unit.

The SCR frame module control unit (A95) reads in the analog signals for the following sensors:

 Temperature sensor upstream SCR catalytic converter (B115)

 Temperature sensor downstream SCR catalytic converter (B116)

 Fill level and SCR AdBlue temperature combination sensor (B117)

 SCR air humidity and air temperature combination sensor (B132)

The analog signals are converted by the SCR frame module control unit (A95) into digital CAN bus signals and transmitted as cyclical status reports to the engine control (MR) control unit.

The signals are processed in the engine control (MR) control unit and the corresponding control signals sent as CAN bus signals to the SCR frame module control unit (A95) which then actuates the following components:

 SCR AdBlue pump (M25)

 SCR air pressure limiter solenoid valve (Y106)

No application data is available in the SCR frame module control unit (A95). Debouncing or storage of error data does not take place in the SCR frame module control unit. This is the task of the engine control (MR) control unit, which receives all necessary information via the CAN bus.

After switching off the ignition, the SCR frame module control unit (A95) runs on until messages are received from the engine control (MR) control unit.