WARNING: This page is about a different car, the 2016 Jeep Wrangler and 2015 Jeep Wrangler. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes
(X301) AMPLIFIED SUBWOOFER 2 (+) CIRCUIT SHORTED TO VOLTAGE
(X391) AMPLIFIED SUBWOOFER 2 (-) CIRCUIT SHORTED TO VOLTAGE