Blind Spot Monitor, function - GF54.71-P-4000LE

MODEL 216 up to 31.8.10 with ENGINE 156, 273, 275 with CODE (233) Distronic Plus with CODE (234) Blind Spot Assist as of model year 2009/YoM 08

MODEL 221 up to 31.8.10 with ENGINE 156, 272, 273, 275, 642, 629 with CODE (233) Distronic Plus with CODE (234) Blind Spot Assist as of model year 2009/YoM 08

Blind Spot Assist function requirements, general

Circuit 61 ON (engine running)
"BSM_AVL" (B lind S pot M onitoring) coded in the central gateway control unit (N93)
Radar sensor system not disabled
"Blind Spot Assist" switched on via the menu in the instrument cluster (A1)
Gear range "D" engaged
Vehicle speed ≥ 30 km/h

Blind Spot Assist, general

Blind Spot Assist (also called BSM (B lind S pot M onitoring)) is available as special equipment (SA) with code 234.

Blind Spot Assist assists the driver in changing lanes safely. Blind Spot Assist supplies important information about the events in the rear and side area of the vehicle where the inside rearview mirror and the two outside mirrors do not offer adequate visibility (blind spots).

This driver assistance system offers the driver a clear comfort advantage and reduces the frequency of accidents.

Blind Spot Assist is controlled and monitored by the radar sensors control unit (SGR) (N62/1).

Blind Spot Assist function sequence

The function sequence is described in the following steps:

Switching on and off function sequence
Indication function sequence
Warning range function sequence
Function sequence for activation
Function sequence for warning message
Function sequence for trailer operation (with model 221 with code (550) Trailer hitch)
Function sequence for deactivation

Switching on and off function sequence

Blind Spot Assist is switched on and off in the "support systems" menu of the instrument cluster (A1) via the left and right multifunction steering wheel button group (S110, S111).

Indication function sequence

The Blind Spot Assist indicators are made up of color-changing triangles in the respective outside mirror.

Warning range function sequence

The warning range in which the detected object is displayed includes approx. 3 m next to and approx. 3 m behind the vehicle.

Function sequence for activation

Activation is not necessary when Blind Spot Assist is switched on. With "ignition ON", the triangles in the outside mirrors light up in red. Blind Spot Assist is automatically activated when the engine is started and the triangles light up in yellow (Blind Spot Assist ready). However, the yellow triangles only disappear at a vehicle speed of >30 km/h and the system can then warn about objects within the warning area.

Blind Spot Assist ready

Fig 1: Identifying Left Blind Spot Assist Readiness And Warning Indicator (Yellow)

Courtesy of MERCEDES-BENZ USA

When the engine is running and Blind Spot Assist is switched on, the yellow triangles in the outside mirrors light up to a speed of 30 km/h.

Object in blind spot (in the warning area)

Fig 2: Identifying Left Blind Spot Assist Readiness And Warning Indicator (Red)

Courtesy of MERCEDES-BENZ USA

The triangles light up or flash red if an object in the warning range is detected.

Function sequence for warning message

If an object is located in the warning range at a speed of 30 km/h, the driver is warned by a red triangle lighting up in the respective outside mirror. If the driver nevertheless attempts to initiate a lane change and signals this by operating the turn signal indicator, then a single acoustic collision warning take place and the red triangle starts to flash.

If the object leaves the warning range, the red triangle goes out again.

Function sequence for trailer operation (with model 221 with code (550) Trailer hitch)

When a trailer is hitched to the vehicle the rear area of the vehicle can no longer be monitored by Blind Spot Monitoring. The warning message "Blind Spot Monitoring currently not available, see operator's manual" is displayed in the instrument cluster and the Blind Spot Assist triangles are switched off.

The radar sensors control unit detects a hitched trailer via a signal from the trailer recognition control unit (N28/1).

Function sequence for deactivation

If the vehicle speed is less than 25 km/h, the red triangles are deactivated and only the yellow triangles still light up. In other words, it cannot warn about any objects that are located in the warning range.

In addition, Blind Spot Assist is deactivated when the vehicle is put into reverse "R".

Electrical function schematic, blind spot assistant	Model 216	PE54.71-P-2051-97CAA
Electrical function schematic, blind spot assistant	Model 221	PE54.71-P-2051-97SAA
Component description for instrument cluster	A1 Model 216.3, 221.0/1 except 221.095/195	GF54.30-P-6000LE
Component description for instrument cluster	Model 221.095/195	GF54.30-P-6000LEH
Component description for trailer recognition control unit	N28/1 Model 221.0/1 with code (550) Trailer hitch	GF31.19-P-4050LE
Component description for regenerative braking system control unit	N30/6 Model 221.095/195	GF42.22-P-1100LEH
Component description for ESP control unit	N47-5 Model 216.3, 221.0/1 except 221.095/195	GF42.45-P-5118LE
Component description for radar sensors control unit	N62/1	GF30.30-P-3301LE
Component description for left door control unit	N69/1 Model 216.3	GF72.29-P-4124LA
Component description for left front door control unit	N69/1 Model 221.0/1	GF72.29-P-4141LE
Component description for left front door control unit	Model 221.1 with code (Z07) Top protection	GF72.29-P-4141LES
Component description for right door control unit	N69/2 Model 216.3	GF72.29-P-4128LA
Component description for right front door control unit	N69/2 Model 221.0/1	GF72.29-P-4142LE
Component description for right front door control unit	Model 221.1 with code (Z07) Top protection	GF72.29-P-4142LES
Component description for steering column tube module	N80 Model 216.3, 221.0/1	GF54.21-P-6050LE