Lost Communication With Battery Energy Control Module A
What it means
U0111 means the vehicle's network has stopped receiving expected messages from the battery energy control module. That module manages the vehicle's battery and energy — on hybrids and EVs it oversees the high-voltage battery, and on conventional cars it handles battery/charge and stop-start energy management. On a hybrid or EV the propulsion system may refuse to start or run in reduced power; on a conventional vehicle you typically lose stop-start and smart-charging behavior.
Can I keep driving? Depends on the vehicle. On a hybrid or EV this can prevent it from starting or drop it to reduced power, so treat it as serious and get it checked; on a conventional car you'll usually just lose stop-start and charge-management features.
Common symptoms
What you'll notice
- Warning light or message related to the affected system
- The battery energy control module's features stop working or work intermittently
- Stored 'lost communication' code in the module that reports the fault
- Battery, hybrid, or charging-system warning message
- Stop-start disabled or reduced-power/limp operation on hybrids and EVs
Common causes
Most likely first
- Power or ground fault feeding the battery energy control moduleLikely
- Damaged wiring or a loose/corroded connector at the battery energy control moduleCommon
- Break in the CAN/bus wiring between the module and the rest of the networkCommon
- The battery energy control module itself has failed internallyLess often
- Low battery voltage or a recent battery disconnect knocking modules off the busLess often
How to diagnose & fix
Work through it in order
- Check battery voltage and charge; a weak battery or recent disconnect is a common, easy cause.
- Scan all modules and confirm whether only the battery energy control module is missing or several are — that narrows wiring vs. module.
- Verify power and ground at the battery energy control module's connector.
- Inspect the connector and harness to the battery energy control module for damage, corrosion, or backed-out pins.
- Check for a manufacturer software update or reflash; if wiring and power are good, replace the failed module. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with U0111?+
Can I just clear U0111?+
Related codes
Often seen with U0111
Read & clear U0111 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.