The procedure below will display diagnostic trouble codes (DTC) to the JK’s odometer.

1. Insert key into ignition, turn to the ON position but do not start the engine.
   
   2013 JK is devoid of marking for On/Off. Photo above shows ignition in OFF position.
   
   Above photo shows ignition in ON position.
2. Turn key to the OFF position then back ON three times rapidly. Make sure to end the sequence in the ON position.
3. All dash lights should illuminate briefly.
   
   Odometer will show a series of six dashes.
   
4. Any DTC codes logged by the system will appear in the odometer. Make note of these.
5. Odometer will show ‘-done-’ following the last reported DTC code or if none logged.
   
6. Turn the key to OFF and remove from ignition.

To better understand the supplied codes, consult the Diagnostic Trouble Code List.