Volvo’s Four-C, short for Continuously Controlled Chassis Concept, is a type of active suspension available on some Volvos starting in model year 2004 (North America).
Fast Volvos Get “Advanced” Setting
The multi-mode suspension — for instance, the driver-selectable modes in a 2004 V70 R are Comfort, Sport and Advanced — was developed by Volvo with input from Swedish suspension company Öhlins. Non-R cars get only two settings, Comfort and Sport.
In enthusiast circles, the system has a mediocre reputation, one complaint being rear-end side-to-side hop over rough patches of roadway, and 2004 models of Volvos supposedly suffering the most.
Sorry, No, They’re Not Cheap
Unfortunately, replacement 4C struts cost an arm and a leg, often topping $1500 for all four. I’m not talking about the whole job with labor but rather just the struts’ cost. This Volvo Forum struts post discusses where to find these special Monroe struts for relatively cheaply… around $1000 for all four.
4C Sensors Monitor Many Signals
The sensors provide about 500 reading impulses a second, measuring parameters such as:
- The car’s speed and acceleration
- Lateral acceleration (when taking a curve)
- The wheels’ suspension movements
- The steering wheel’s position and how fast it is turned
- The engine’s current (calculated) torque
- The degree of braking
Below is my 2004 V70 R’s factory strut.