Observe the "Important safety notes" section.

WARNING
ESP® should not be deactivated during normal driving other than in the circumstances described below. Disabling the system will reduce vehicle stability in driving maneuvers.
Do not deactivate ESP® when the emergency or spare wheel is mounted.

WARNING
S 63 AMG: ESP® should not be deactivated during normal driving.
Deactivating the system results in the following:
• no restriction to the engine torque
• loss of system-supported traction control
"ESP OFF" is designed for driving on closed tracks when the vehicle's own oversteering and understeering characteristics are desired and requires an extremely qualified and experienced driver who is able to handle these critical driving situations.
You could lose control of your vehicle and cause an accident.
Beware of these limits if you deactivate ESP®.
Do not deactivate ESP® when the emergency or spare wheel is mounted.

ESP® is activated automatically when the engine is started.

Vehicles with ECO start/stop function: the ECO start/stop function switches the engine off automatically when the vehicle comes to a stop. The engine starts automatically when the driver wants to pull away again. ESP® remains in its previously selected status. Example: if ESP® was deactivated before the engine was switched off, ESP® remains deactivated when the engine is switched on again.

It may be best to deactivate ESP® in the following situations:
• when using snow chains
• in deep snow
• on sand or gravel

WARNING
Switch on ESP® immediately if one of the previously stated conditions is no longer met.
Otherwise, ESP® cannot stabilize the vehicle if it begins to lurch or when a wheel spins.

When you deactivate ESP®:
• ESP® no longer improves driving stability.
• the engine's torque is no longer limited and the drive wheels can spin. The spinning of the wheels results in a cutting action, which provides better grip.
• traction control is still activated.
• ESP® still provides support when you brake.

If ESP® is deactivated and one or more wheels start to spin, the ESP® warning lamp in the instrument cluster flashes. In such situations, ESP® will not stabilize the vehicle.

To deactivate:
The ESP® OFF warning lamp in the instrument cluster lights up.

WARNING
When the ESP® OFF warning lamp is lit, ESP® is deactivated.
If the ESP® warning lamp and the ESP® OFF warning lamp remain lit, ESP® is not available due to a malfunction.
When ESP® is deactivated or not operational, vehicle stability in standard driving maneuvers is reduced.
Adapt your speed and driving to the prevailing road conditions and to the non-operating status of the ESP®.

Avoid spinning the driven wheels for an extended period with ESP® deactivated.
You could otherwise damage the drivetrain.

To activate:
The ESP® OFF warning lamp in the instrument cluster goes out.