System Overview

System overview

Control module




The task of the suspension module (SUM) is to manage the functions for Four-C (Continuously Controlled Chassis Concept). Four-C is a system that continuously controls damping in the shock absorbers to affect the behavior and comfort of the vehicle. The suspension module (SUM)is located on the base plate under the rear seat backrest.
The control module continually receives signals from different sensors to calculate the vehicle's position and movements. By individually controlling damping in the shock absorbers, the system works to achieve the best possible comfort and road grip.
The suspension module (SUM) reads off and controls directly connected components and sensors. The system also communicates with other control modules and components via CAN communication.
The suspension module (SUM) has integrated self diagnostics that check input and output signals to detect damaged components and wiring. If the control module detects a fault, the current diagnostic trouble code (DTC) is stored at the same time as the control module continues the system in fail-safe mode. In this case, the shock absorbers function as normal passive shock absorbers. When a fault is detected an error message is also transmitted to the Driver information module (DIM) to warn the driver.
Diagnostic trouble codes (DTCs) that are stored in the control module's memory can be read off using the diagnostic tool.
An easy way to check whether the suspension module (SUM) is powered is to change driving mode via the switch and check that it changes. See Function, Changing the driving mode. If the driving mode does not change, this could mean that the control module has disengaged the switch, which can occur if there is a fault in the switch.
If the voltage falls below 9 V or exceeds 16.0 V, the system continues in fail-safe mode.
For further information, also see Signal specifications.

Signals
The table below summarizes the input signals to and output signals from the suspension module (SUM). The signals are divided into directly connected signals and CAN communication. The illustration below displays the same information with the Volvo component designations