Hybrid and EV

U0111 — Lost Communication with Battery Energy Control Module

Severity: high Drive with care, to a shop

What U0111 means

U0111 means one or more control modules stopped receiving messages from the hybrid battery energy control module over the CAN bus. That module monitors cell voltage, temperature and state of charge and reports to the hybrid system controller. Without that data the system cannot safely manage the battery or high-voltage output.

Symptoms

  • Hybrid system warning light
  • READY indicator does not come on
  • Several warning lamps on at once
  • Features that depend on the battery module are unavailable
  • Reduced power or engine-only operation

Possible causes

  1. Failed hybrid battery control module
  2. Service plug removed or not fully seated
  3. Open, shorted or chafed CAN wiring to the battery pack
  4. Corroded connectors or terminals
  5. Power supply or ground fault at the module
  6. Another faulty module loading the CAN bus
  7. Internal high-voltage battery fault

How to diagnose

  1. Run a full-system scan and map which modules are not communicating
  2. Look for other codes related to the battery, power supply or CAN bus
  3. Confirm the high-voltage service plug is installed and locked
  4. Check 12 V battery condition, terminals and fuses
  5. Measure CAN bus resistance and voltages at the diagnostic connector
  6. Inspect the battery module harness and connectors for damage, moisture and corrosion
  7. Check module power and ground using the factory wiring diagram
  8. Disconnect suspect modules one at a time, only with a documented procedure

Common fixes

  • Repair or replace damaged CAN wiring
  • Clean or replace corroded connectors and terminals
  • Restore the module's power or ground connection
  • Reseat the service plug correctly
  • Replace or reprogram the battery control module
  • Repair the battery or replace the faulty module that disrupts the bus

Questions and answers

What does U0111 mean?

It means communication was lost with the hybrid battery energy control module. Other modules cannot get its data over the CAN bus, so the hybrid system may be limited or shut down.

Can I drive with U0111?

It is risky. The car may lose power or shut down the hybrid system without warning. If it runs, drive only a short distance to a repair shop.

What most often causes U0111?

Common causes are CAN wiring or connector faults, a power or ground problem at the module, a poorly seated service plug, or a failed battery control module. Start with wiring and power checks.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.