diff --git a/How-to-build.md b/How-to-build.md
index 33aa0b4..c7bc041 100644
--- a/How-to-build.md
+++ b/How-to-build.md
@@ -164,4 +164,7 @@ Be aware that both display cables twist 180 degrees.
 
 ![image](https://dl.dropboxusercontent.com/s/08ql5k0zarpqxfo/IMG_1584.jpg?dl=1)    
 
- 
\ No newline at end of file
+## 11) Self Test   
+Now that everything is build you should do the self test you can find on the second page of the main menu.   
+It checks if the pins are shorted either to GND or to each other. It also checks the 1K resistor and activates the clock generator.    
+You can learn more about the self test [here](https://github.com/sanni/cartreader/wiki/Troubleshooting#self-test).    
\ No newline at end of file