Engine Sound Control Unit, Component Description - GF54.21-P-0019RF

Model 205 as of Model year 2019 with code B63 (Engine sound via speakers) except code 810 (Premium sound system) except code 853 ("Midline" sound system)

Model 205 up to Model year 2019 with code B63 (Engine sound via speakers)

Model 253 up to Model year 2020 with code B63 (Engine sound via speakers)

Shown: Model 205.0

Fig 1: Engine Sound Control Unit Components Location - Model 253 Up To Model Year 2020 With Code B63 (Shown On Model 205.0)

Courtesy of MERCEDES-BENZ USA

Location

The engine sound control unit is located behind the paneling in the front passenger footwell.

Task

The engine sound control unit simulates the sound of the engine and exhaust system, which in the original cannot be fully heard in the vehicle interior. The simulated sound is output via the speaker system, even when no audio source is active.

For this purpose, the engine sound control unit implements the following tasks:

Reading in of sensors and signals
Evaluation of input factors
Actuation of components

Reading in of sensors and signals

The engine sound control unit reads in the input factors via the following connections:

Direct lines
Drive train CAN (CAN C1)

Direct lines

The engine sound control unit reads in control signals for the speaker system from the head unit (A26/17) via direct lines.

Drive train CAN

The engine sound control unit also reads in signals over the drive CAN:

Circuit status
On-board electrical system status
Drive program selection (automatic transmission)
Engaged drive range (automatic transmission)
Vehicle speed
Engine running status
Engine speed
Engine torque

Evaluation of input factors

The input factors that are read in are evaluated by the integrated microprocessor, and the audio signals are output.

Actuation of components

The engine sound control unit on vehicles except code 810 (Sound system) actuates the following component parts over direct lines:

Left footwell woofer (right-hand drive vehicles) (H4/42)
Right footwell woofer (left-hand drive vehicles) (H4/43)
Left front door midrange speaker (H4/72)
Right front door midrange speaker (H4/73)
Left rear door/side trim midrange speaker (H4/80) (except Model 205.3/4)
Right rear door/side trim midrange speaker (H4/81) (except Model 205.3/4)
Left rear side wall trim midrange speaker (H4/102) (Model 205.3/4)
Right rear side wall trim midrange speaker (H4/103) (Model 205.3/4)

Model 205 up to Model year 2019, Model 253 with code 810 (Sound system)

The engine sound control unit sends the synthesized sound signals over the same direct lines to the sound system amplifier control unit (N40/3). The sound system amplifier control unit actuates the speaker system accordingly.

	Wiring diagram of engine sound control unit	Model 205 up to Model year 2019 with code B63 (Engine sound via speakers) Model 253 up to Model year 2020 with code B63 (Engine sound via speakers)	PE54.21-P-2148-97FBA
		Model 205 as of Model year 2019 with code B63 (Engine sound via speakers) except code 810 (Premium sound system) except code 853 ("Midline" sound system)	PE54.21-P-2148-97FBB