The Technical Definition: The Body Control Module, which manages interior electronics and body functions, has stopped communicating over the CAN bus network.

Common Symptoms: You will experience malfunctioning interior electronics, such as power windows and door locks failing to operate, accompanied by illuminated warning lights.

Typical Fix: Similar to other U-codes, fully load testing and replacing a weak main or auxiliary battery is the most common fix on modern Wranglers. If power is good, check for loose grounds or corroded wiring harnesses going into the BCM behind the glove box.