Fix error code 'Collision sensor active' on Husqvarna Automower 310,315,315X

The error code 'Collision sensor active' is quite common for some Husqvarna Automower models. More exact Automower 310,315 and 315X which was manufactured before 2018.
This guide can also help you if your Automower is stopping frequently in the middle of the lawn and changes direction. As if the collision sensor were activated (but it's not colliding into anything).
This is due to the collision pillar design which allows dirt and grass to be stuck underneath the collision pillars. Most of the times the problem is solved by removing the collision pillars and cleaning underneath, as shown below:

Required tools: Torx screwdriver T20.

Step 1: Turn your Automower upside-down and disconnect the charging contacts.	Step 2: Remove the chassis. You do this by pulling the chassis upwards with one hand while keeping the Automower in place with your other hand.
Step 3: Locate the four screws holding the collision pillars, as shown in the image. Unscrew these four torx-screws.	Step 4: Remove the collision pillars. You will most likely see a bit of grass and dirt stuck under here, this causes problems for the collision sensors. Clean and remove all grass/dirt.
Step 5: After it's cleaned no grass or dirt should be left.	Step 6: Place the collision pillars back and tighten the four torx screws.
Step 7: Install the chassis and connect the charging wire. Lastly put back the plug for the charging contacts.

When this procedure is done your Automower will most likely work as intended. If it still gives you the error code 'Collision sensor active' it is most likely on of the collision sensor circuitboards which needs to be replaced.