U0112
Lost Communication with Battery Energy Control Module "B"
The Battery Energy Control Module "B" has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. The second battery-energy controller is silent, limiting high-voltage system availability. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
Ordered by how often each turns out to be the cause.
- BEM-B unpoweredCommon
- CAN wiring to BEM-B brokenPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Battery Energy Control Module
- CAN Bus Wiring
U0112 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.