Downhill Speed Regulation, function - GF28.19-P-3600GZ

MODEL 164.1

MODEL 164.8

Fig 1: Downhill Speed Regulation Function Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The Downhill Speed Regulation is a system for limiting the vehicle speed when driving downhill.

Using the Downhill Speed Regulation switch (N72s30) in the lower control panel control unit (with Offroad package, code 430) or the Downhill Speed Regulation switch (N72/1s24) in the upper control panel control unit (without Offroad package), the driver can switch the Downhill Speed Regulation on or off.

The signal "Switch ON" is received by the ESP control unit. A red LED integrated in the Downhill Speed Regulation switch indicates whether the speed limiter is active. If any variable speed limiter (e.g. cruise control) is already set, it is switched off when the Downhill Speed Regulation is activated.

The minimum speed setting for the Downhill Speed Regulation is approx. 4 km/h.

The speed setting of the Downhill Speed Regulation can be preset between 4 and 18 km/h in increments of 2 km/h in the multifunction display (A1p13) in the instrument cluster using the cruise control switch. The speed setting can also be varied while actually driving downhill.

When the vehicle is accelerated, the Downhill Speed Regulation switches to "passive".

When the vehicle speed drops below a threshold value of 35 km/h, the Downhill Speed Regulation resumes regulating the speed to the previously set speed setting.

If the vehicle speed exceeds a threshold value of 35 km/h, the Downhill Speed Regulation and the function LED in the Downhill Speed Regulation switch are switched off. In addition, an abort message is displayed via the multifunction display in the instrument cluster.

Function requirements

The following conditions must be satisfied in order to activate the Downhill Speed Regulation:

Vehicle speed < 30 km/h
Downhill Speed Regulation switched on via the Downhill Speed Regulation switch
Speed setting of the Downhill Speed Regulation preset (in increments of 2 km/h, from 4 to 18 km/h) in the instrument cluster (possible immediately after ignition ON)

Function abort

Downhill Speed Regulation is aborted under the following conditions:

Downhill Speed Regulation is switched off via the Downhill Speed Regulation switch
Vehicle speed > 35 km/h

Cruise control switch, component description

S40, S40/4

GF30.20-P-2100GZ