4X00IN Information on PSM

WM 4X00IN Information on PSM

Information on PSM

PSM is an active control system to stabilise the vehicle at the limit of driving dynamics. Sensors continuously determine:
- Vehicle speed
- Direction of travel (steering angle)
- Lateral acceleration
- Longitudinal acceleration
- Rotation rate

Information

- The PSM (Porsche Stability Management) is automatically ready/switched on after each engine start.

Information on PSM

The vehicles are equipped with a new PSM generation with enhanced functions, which considerably improve active safety.
- Enhanced braking readiness
- Brake assist function
- Enhanced Trailer Stability Management
- New ABS tuning for braking on loose surfaces

With enhanced braking readiness, the brake system builds up slight pressure when the accelerator is released quickly and places the brake pads lightly on the brake discs. If the driver now presses the brake, braking power can be achieved more quickly. This results in a shorter stopping distance. Enhanced braking readiness always remains active, irrespective of whether PSM is on or off.

On identifying full braking - when a defined pedal pressure is exceeded - brake assist supplies the required pressure for maximum deceleration via the PSM hydraulic unit. Brake assist can be deactivated by switching off PSM.

Enhanced Trailer Stability Management is a support function of PSM for driving with a trailer. The system detects swaying movements of the trailer and tries to minimise these through targeted braking. Trailer Stability Management can be switched off by switching off PSM. When the driver presses the brake pedal, Trailer Stability Management is activated even if PSM is switched off.

The ABS control strategy has been modified for braking on loose surfaces. A brake barrier, which helps to reduce braking distance on gravel or snow for example, is created in front of the tyres by blocking the wheels short.

Switching off PSM

Press the PSM switch. The PSM switches off after a short delay.

When the PSM is off, the PSM OFF warning light in the instrument panel and the indicator light in the switch are lit.
- When braking, the vehicle is also stabilised when the PSM is switched off!
- One-sided wheel spin is also prevented when the PSM is switched off!

The PSM should always be switched on for normal driving.

In the following exceptional cases, it can be advantageous to switch off the PSM temporarily:
- On a loose surface and in deep snow
- When rocking the vehicle free
- When using snow chains
- On extremely rough ground (if one or more wheels have little or no road grip - engine performance is reduced)

Switching PSM back on

Press the PSM switch. PSM switches on after a short delay.