2. Turn it to the OFF position
3. Turn it to the ON position
4. Turn it to the OFF position
5. Turn it to the ON position and leave the key in this postion.
The dash cluster now will show the error codes (if there are any).
And here's a list of codes and what they mean: https://project-jk.com/jeep-jk-write-ups/jeep-jk-wrangler-diagnostic-trouble-codes-dtc-how-to-check-them-what-they-mean