Volvo 2008 V70 Owner's Manual page 143

A pulsating sound will be audible when the system is actively operating and is normal.
Traction control (TC)
This function is designed to help reduce wheel spin by transferring power from a drive wheel that begins to lose
traction to the wheel on the opposite side of the vehicle (on the same axle).
TC is most active at low speeds.
This is one of DSTC's permanent functions and cannot be switched off.
Active Yaw Control (AYC)
This function helps maintain directional stability, for example when cornering, by braking one or more of the wheels if
the vehicle shows a tendency to skid or slide laterally.
This is one of DSTC's permanent functions and cannot be switched off.
Spin control (SC)
The spin control function is designed to help prevent the drive wheels from spinning while the vehicle is accelerating.
Under certain circumstances, such as when driving with snow chains, or driving in deep snow or loose sand, it may be
advisable to temporarily switch off this function for maximum tractive force.
WARNING
The car's handling and stability characteristics will be altered if the spin control function has been disabled.
Operation
Temporarily switching off Spin control
1. Turn the thumbwheel
2. Hold down the RESET button
Messages in the information display
DSTC Temporarily OFF
function is activated automatically when the brakes have cooled.
DSTC Service required
154
04 Comfort and driving pleasure
Stability system
until the DSTC menu is shown.
to toggle between
- system function has been temporarily reduced due to high brake disc temperature. The
- the system has been disabled due to a fault. If this occurs:
DSTC SPIN CONTROL ON or OFF.