U0111: Lost communication with the battery energy control module

Lost communication with battery energy control module "A"

Severity: Inspect soon

Owners report sudden power loss in traffic and a car that will not move with U0111 on hybrids and EVs. The part involved is the high-voltage battery controller, so have it inspected soon.

It gets more serious if:

Stop: Stop if the vehicle loses drive power or shows a reduced-power or shutdown warning while driving: pull over where safe and arrange a tow.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

U0111 in short

U0111 means the vehicle lost communication with the battery energy control module, the controller for a hybrid or EV battery. Causes seen are the module, a software update need, a plugged-in third-party OBD device, or wiring. Owners report sudden power loss, so have it inspected soon; high-voltage work is for a shop.

On hybrids and electric vehicles a battery energy control module watches the high-voltage battery and reports to the other computers. When its messages stop, other modules store U0111.

Complaints include a Subaru Solterra that lost power in traffic, a Volvo S60 that would not move until restarted, and a Ford Focus Electric with battery contactor codes. A 2008 Prius cleared its U0111 once a third-party telematics device was unplugged from the OBD port. GM issued an information note for 2011-2013 Volts with U0111 to update the module calibrations.

The code does not say why contact was lost, so scan every module for related codes before deciding.

Most likely causes

Cause 1: Battery energy control module or battery communication fault
Supported by vehicle data
Why it ranks here
Owners of several makes report power loss with U0111 and battery codes such as P0A1F or P0AA2, which point at the battery control side.
What would change this
Rises if battery-system codes are stored with U0111. Falls if no battery codes are present and the code clears.
Cause 2: Module calibration needing an update (2011-2013 Volt)
Supported by vehicle data
Why it ranks here
GM PIC5829 covers 2011-2013 Volts with U0111 and says to update the BECM calibrations; only the NHTSA summary was read.
What would change this
Rises on those Volts. Falls on other vehicles.
Cause 3: Third-party device on the OBD port
Possible — needs testing
Why it ranks here
A 2008 Prius with U0100 and U0111 stopped repeating once a telematics device was removed; this is one report.
What would change this
Rises if a plug-in dongle is installed and the codes began after it. Falls if no device is fitted.
Cause 4: Wiring or network fault
Common general cause
Why it ranks here
AA1Car says a lost-communication code does not say which part failed and needs further testing.
What would change this
Rises with other lost-communication codes. Falls if only U0111 is stored.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Check whether a plug-in device (insurance tracker, dongle) is on the OBD port; with the vehicle off, unplug it, clear the codes and see whether U0111 returns.
Low risk
- IfU0111 does not return
  It meansThe device was likely interfering.
  Points to: Third-party device on the OBD port
- IfU0111 returns, or no device is fitted
  It meansScan all modules.
  Go to step 2
Step 2: Scan every module with a tool that reads hybrid or EV systems and note battery, contactor or lost-communication codes stored with U0111.
Low riskTool: scan tool that reads hybrid modules
- IfBattery-system codes such as P0A1F or P0AA2 are stored
  It meansThe battery control side is the likely fault; go to a dealer.
  Go to step 3
- IfMany modules show lost-communication codes
  It meansLook for a network or power problem.
  Points to: Wiring or network fault
Step 3: Have a dealer test the battery control module and check for calibration updates or bulletins for your VIN.
Best left to a shop
Warning:Hybrid and EV batteries are high voltage. Only a trained technician should test them.
- IfA calibration update applies
  It meansUpdate before replacing parts.
  Points to: Module calibration needing an update (2011-2013 Volt)
- IfThe module or its wiring fails testing
  It meansRepair or replace it.
  Points to: Battery energy control module or battery communication fault

Symptoms

Sudden loss of drive power Gets more serious: stop and have it checked.
Vehicle will not move or start until restarted
Check engine light and reduced-power warnings

Compare with: Check engine light with loss of power

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

On your vehicle

Chevrolet

2011–2013 · Volt
Supported by vehicle data
GM PIC5829 covers 2011-2013 Volts that set U0111 and calls for a BECM calibration update. Whether it is still current is not verified.

PIC5829Status unverified
SES light with U0111, update the Battery Energy Control Module
2011–2013volt · NHTSA 10112909
Update the BECM with the latest calibrations when U0111 is stored with the service engine soon light on.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Land Rover

2019–2021
Supported by vehicle data
Land Rover SFCC_DEC2020_31 covers 2019-2021 Range Rover and Range Rover Sport that set U0111-00 in the PCM after an update. Whether it is still current is not verified.

SFCC_DEC2020_31Status unverified
PCM U0111-00 after update
2019–2021range-rover, range-rover-sport · NHTSA 10185162
PCM stores U0111-00 Lost Communication With Battery Energy Control Module A after a software update. The NHTSA summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

No curated relationships for U0111 yet.

All Module network (CAN bus) communication codes

U0111 questions

Can a plug-in OBD device cause U0111?

In one Prius report the code stopped once a third-party device was removed. If you have a dongle fitted, unplug it and see if the code returns.

Sources and review

NHTSA complaint ODI 11751170: 2026 Subaru Solterra — NHTSA (owner complaint)
NHTSA complaint ODI 11485063: 2022 Volvo S60 — NHTSA (owner complaint)
NHTSA complaint ODI 11584198: 2017 Ford Focus Electric — NHTSA (owner complaint)
GM PIC5829: SES light with U0111, update the Battery Energy Control Module (2011-2013 Volt) — NHTSA (manufacturer communication)
NHTSA complaint ODI 10649235: 2008 Toyota Prius — NHTSA (owner complaint)
CAN bus U-codes — AA1Car Auto Diagnosis
Land Rover SFCC_DEC2020_31: PCM U0111-00 after update (2019-2021 Range Rover, Range Rover Sport) — NHTSA (manufacturer communication)

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Battery energy control module or battery communication fault

Cause 2: Module calibration needing an update (2011-2013 Volt)

Cause 3: Third-party device on the OBD port

Cause 4: Wiring or network fault

What to test first

Step 1: Check whether a plug-in device (insurance tracker, dongle) is on the OBD port; with the vehicle off, unplug it, clear the codes and see whether U0111 returns.

Step 2: Scan every module with a tool that reads hybrid or EV systems and note battery, contactor or lost-communication codes stored with U0111.

Step 3: Have a dealer test the battery control module and check for calibration updates or bulletins for your VIN.