Controlling The Adaptive Cruise Control
Controlling the adaptive cruise control
Controlling the adaptive cruise control
Note! The V40 (2013-) does not have a PBM (4/115).
The function adaptive cruise control is an extension of the existing cruise control. If there is no vehicle ahead, the speed will remain unchanged just like for conventional cruise control. Speed is set by the driver in a similar way to conventional cruise control.
If there is a vehicle ahead traveling at a lower speed than the set speed, the speed will adjust itself automatically so that the set time gap to the vehicle ahead is attained. In this case, the adaptive cruise control in Forward Sensing Module (FSM) controls the Engine control module (ECM) and, if necessary, also Brake control module (BCM) to maintain the set time gap.
The time interval to the vehicle in front is set by the driver in five steps, in the interval 1 to 2.5 seconds.
When the system is activated, the last selected interval from the previous driving cycle is used.
To change the interval setting, the driver presses one of the buttons on the Steering wheel switch left (SWSL) to increase or reduce the interval. Steering wheel switch left (SWSL) transmits information via LIN communication to Central electronic module (CEM) (4/56), stating which button has been activated. The Central electronic module (CEM) forwards the information via the CAN network to the Forward Sensing Module (FSM) (4/80).
On vehicles with manual transmission the function adaptive cruise control is limited to a speed higher than approx. 30 km/h.
Vehicles with automatic transmission also have a function making it possible to adapt the speed to the vehicle in front even below 30 km/h. Should the vehicle in front stop, the adaptive cruise control will stop the vehicle and hold it still using the service brake. To activate the cruise control below 30 km/h, a vehicle in front is required to be within a reasonable distance. Note that the lowest speed that can be programmed for the cruise control is 30 km/h - even if the cruise control is able to follow another vehicle down to a standstill, a lower speed cannot be selected.
The service brake only keeps the vehicle stationary for a maximum of 240 seconds, after that the parking brake (not V40 (2013 -)) takes over automatically to hold the vehicle stationary. When the preceding vehicle moves off, and the car has been stationary for less than 3 seconds, the adaptive cruise control activates itself automatically.
The parking brake will also be applied automatically when the adaptive cruise control has followed a vehicle to standstill and the driver's door is opened, the seat belt is unbuckled, the engine is switched off or a system error occurs (not V40 (2013 -)). However, if the car has been stationary for longer than 3 seconds the driver must reactivate the adaptive cruise control so the vehicle can follow after. Reactivation is done by pressing the resume button or with a light push of the accelerator
The cruise control be disengaged temporarily due to certain driver actions:
- using the service brake
- pressing down the clutch pedal for longer than 1 minute
- moving the gear selector to neutral position (automatic transmission)
- the driver maintains a higher speed than the set speed for longer than 1 minute.
Thereafter the driver has to control the speed. A temporary speed increase with the gas pedal, e.g., when overtaking, does not affect the cruise control's setting - the car returns to the latest stored speed when the gas pedal is released.
The adaptive cruise control is dependent on other systems in the vehicle. If any of these systems stop working the cruise control is turned off automatically. At automatic deactivation a signal sounds and message for Cruise Control Disengaged is shown in the display. Then the driver has to take action and adapt speed and distance to the vehicle in front.
An automatic deactivation may be due to:
- engine rpm is too low/high
- wheels lose traction
- brake temperature is high
- Forward Looking Radar (FLR) is covered by, e.g., wet snow or in case of heavy rain (radar waves blocked).
Note! To activate the adaptive cruise control, the driver must have closed the door and buckled the seat belt. This is one way to ensure that the driver is in the car, before allowing activation.
Note! The driver always has to pay attention to traffic conditions and take action when the adaptive cruise control does not maintain suitable speed or suitable distance.
Note! The adaptive cruise control is not a collision-avoiding system. The driver must take action if the system does not detect a vehicle in front.