GF30.30-P-0001FL Cruise Control (CC), Function

GF30.30-P-0001FL Cruise Control (CC), Function
- with CODE (440) Cruise control

Component Identification:

The cruise control function belongs to the driver assistance systems and is integrated in the Electronic Stability Program control unit (N30/4). The cruise control also includes the following functions:
^ Permanent Speed Limiter
^ Variable Speed Limiter (except code (494) USA version)

Variable and permanent speed limiters are also called Speedtronic control systems.

Cruise control function requirements
^ Circuit 61 "ON" (engine running)
^ Cruise control coded in the front SAM control unit with fuse and relay module (N10/1)
^ Electronic Stability Program (ESP) not deactivated
^ Electronic Stability Program active (no fault)
^ Vehicle speed ≥30 km/h
^ Parking brake not applied
^ Gear range "D" engaged (for an automatic transmission)
^ Cruise control lever (S40/4) in position cruise control (LIM indicator lamp (LIMITER) off) (except code (494) USA version)

Cruise control - general
The cruise control maintains the constant speed specified by the driver, irrespective of engine load condition and without the accelerator pedal being actuated.

The signals from the cruise control lever are detected by the steering column tube module control unit (N80) and transmitted via the chassis CAN
(CAN E) to the Electronic Stability Program control unit.
The specified speed is transmitted by the Electronic Stability Program control unit via the chassis CAN to the instrument cluster.
The acceleration or deceleration requests (to intervene in the engine control) are sent by the Electronic Stability Program control unit via the chassis CAN to the CDI control unit (N3/9) (for diesel engines) or the ME-SFI [ME] control unit (N3/10) (for gasoline engine).

A switching request at the automatic transmission is transmitted from the Electronic Stability Program control unit via the chassis CAN and drive train CAN (CAN C) to the electronic transmission control control unit (N15/3) (for transmission 722.6) or to the fully integrated transmission control controller unit (Y3/8) (for transmission 722.9).

Function sequence for cruise control
The function sequence is subdivided into the following steps:
^ Function sequence for activation
^ Function sequence for speed control
^ Function sequence for deactivation

Function sequence for activation
Pulling out the cruise control lever or moving it up or down activates the cruise control starting from a vehicle speed of 30 km/ h.
If the cruise control lever is moved up or down, the current vehicle speed is stored as the specified speed and either raised or lowered depending on whether the pushbutton is moved up or down.
If the cruise control lever is pulled out, the last specified speed stored is applied, provided a specified speed has been stored since the last engine start. If no specified speed has been stored, the cruise control sets the current vehicle speed as the specified speed.
The cruise control lever can be moved up or down to different degrees to increase or reduce the specified speed in 1 km/h or 10 km/h increments (two settings).

If the cruise control is activated, the segments in the speedometer (A1p8) are illuminated from specified speed to end of the tachometer scale.

Function sequence for speed control
When the vehicle is approaching the specified speed, engine power is automatically reduced. If this is not enough to prevent the vehicle exceeding the specified speed for example, on a steep downward gradient), the service brake is applied and modulated and the automatic transmission downshifted as necessary.

If the vehicle is accelerated above the specified speed (for example, when overtaking), the cruise control reapplies the specified speed after the accelerator pedal is released.

Function sequence for deactivation
The cruise control mode is deactivated if:
- The cruise control lever is pushed to the front
- The cruise control lever is pressed in the Variable Speed Limiter position to switch over (LIM indicator lamp is lit) (except code ( 494) USA version)
- The brake pedal is operated.
- Parking brake is actuated
- Gear range "P" or "N" engaged (for automatic transmission)
- ESP operates
- ESP switched off
- ESP deactivated (a fault)
- Vehicle speed <30 km/h
- Clutch pedal actuated for less than 6 s (with manual transmission)
- An excessively high gear is engaged and therefore the motor speed drops too quickly (for a manual transmission)
- Circuit 15 OFF (ignition OFF)

These functions are described in the following documents:
^ Variable Speed Limiter (except code (494) USA version)
^ Permanent Speed Limiter