System Overview

System overview

Introduction
The Forward Sensing Module (FSM) is an electronic system whose main task is to warn and aid the driver to brake the vehicle in the event of an imminent collision. Parts of the system supplement the existing cruise control.

The following functions are provided by the Forward Sensing Module (FSM):
- Collision warning, warns the driver of a possible collision with approaching vehicles.
- Brake assistance in the event of a possible collision, aids the driver to brake the vehicle when the brake pedal is depressed.
- Adaptive cruise control, maintains a time distance to the vehicle ahead when cruise control is activated.

Control module





The most important task of the Forward Sensing Module (FSM) is to manage the functions for:
- Collision warning
- Brake assistance in the event of a possible collision
- Adaptive cruise control
The control module is located in front of the glove compartment inside/below the dashboard. The entire control module is removed from the vehicle during replacement.
The Forward Sensing Module (FSM) communicates both with directly connected components and with other control modules via CAN communication.
The control module checks its calculations and all carried out activations, input and output signals using built-in diagnostic functions. A diagnostic trouble code (DTC) is stored if the control module detects a fault. In certain cases, the incorrect signal is replaced with a substitute value.
Any diagnostic trouble codes (DTCs) are stored in the control module memory. The data can be read off using the diagnostic tool.
If the control module detects a malfunction, a diagnostic trouble code is registered inside the control module's internal memory. At the same time, a number of values are stored. These are frozen at the time the malfunction occurred. Depending on the severity of the malfunction, certain functions may be partially or completely disengaged. Diagnostic trouble codes and frozen values (extended diagnostic trouble code information) can be read off using diagnostic tools via the data link connector in the vehicle.
Select ignition position II and press the button to activate collision warning to check whether the Forward Sensing Module (FSM) is grounded and powered. Check that the LED in the button is lit and that the Driver information module (DIM) displays the symbol for collision warning, and a text message.
For further information, also see Signal specifications.

Signals
The table below summarizes the input signals to and output signals from the Forward Sensing Module (FSM). The signal types are divided into directly connected signals, serial communication and controller area network (CAN) communication. The illustration below displays the same information with the Volvo component designations.