What it means
A control module has lost communication with the battery energy control module. On applicable hybrid or electric vehicles, battery-related functions may be limited or unavailable.
How it works
The battery energy control module monitors and coordinates battery-related functions on applicable hybrid and electric vehicles. Other modules expect it to share status over the vehicle network; U0111 sets when those messages are lost. This code alone does not identify a battery-pack failure or establish why communication stopped.
Common causes
Most likely first.
- Loss of module power or ground
- Open, shorted, or damaged communication wiring or connector
- Module or gateway fault
Symptoms
- Hybrid or electric system warning
- Reduced or unavailable vehicle functions may occur
- Communication faults in other modules
How to diagnose it
- Save the all-module scan and freeze-frame data, identifying which modules report lost communication with the battery energy control module.
- Check the 12-volt battery and inspect the relevant low-voltage fuses, power supply, and ground connections for the module.
- Visually inspect accessible low-voltage connectors and network wiring for damage, corrosion, or water entry; leave high-voltage components untouched.
- Use a compatible scan tool to see whether the battery energy control module responds and whether battery or hybrid-system warnings are present.
- If low-voltage power and ground are correct but the module remains offline, test the communication bus and gateway route according to the manufacturer's procedures.
Common fixes
- Charge or replace a weak 12-volt battery and repair poor connections.
- Replace a failed low-voltage fuse or repair the module's power or ground connection.
- Repair damaged network wiring or clean and secure an accessible low-voltage connector.
- Repair a confirmed gateway fault interrupting communication with the battery energy control module.
- Replace or reprogram the module only after its low-voltage supply and network path pass testing.
Can I keep driving?
If a hybrid or electric system warning or reduced vehicle function appears, avoid relying on the vehicle for a long trip because it may limit operation or fail to restart. Stop safely if propulsion becomes unreliable, and do not handle high-voltage components.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.