• Manual
  • Software updates

Trailer stability assist*

The function of trailer stability assist (TSA1), which is included in the stability system ESC2, is to stabilise a car towing a trailer in situations where the car/trailer combination starts to snake. The function is added during the installation of the towbar, contact Polestar Customer Support for more information.

Reasons for snaking

The snaking phenomenon can occur with any car/trailer combination. Snaking normally occurs at high speeds. However, there is a risk of it occurring at lower speeds if the trailer is overloaded or the load is improperly distributed, e.g. too far back.

Triggering factors for snaking may, for example, include:

  • Car with trailer subjected to a sudden and powerful side wind.
  • Car with trailer drives on an uneven road surface or in a pothole.
  • Sweeping steering wheel movements.

Once the car has begun to fishtail, it may be difficult or impossible to stop it doing so. This makes the vehicle combination difficult to control, with a risk of it ending up in the wrong lane or leaving the roadway.

Trailer stability assist function

The trailer stability assist function continually monitors the car's movements, particularly lateral movements. If snaking is detected, the front wheels are individually braked. This serves to stabilise the car/trailer combination. This is often enough to help the driver regain control of the car.

If the car is not brought back under control despite the initial input from trailer stability assist, all wheels are used in tandem to brake the vehicle combination and the electric motor's drive is reduced. Once snaking has been gradually suppressed and the car/trailer combination is stable once again, the system stops regulating and the driver once again has full control of the car.


The stability function is deactivated if ESC Sport Mode is activated in the centre display.

Trailer stability assist may fail to intervene if the driver uses severe steering wheel movements to try to rectify the snaking because in such a situation the system cannot determine whether it is the trailer or the driver causing the snaking.

PS2-2007-Electronic Stability Control symbol

When Trailer Stability Assist (TSA) is operating, the ESC symbol flashes in the driver display.


Retrofitting the towbar requires an update of the car's software, contact Polestar Customer Support.
  1. * Option/accessory.
  2. 1 Trailer Stability Assist
  3. 2 Electronic Stability Control