What it means
ECU lost CAN communication with battery energy control module D (hybrid/EV high-voltage battery management).
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
Battery Energy Control Module D is part of the hybrid or EV high-voltage battery management system and communicates battery information to other controllers over CAN. U014C sets when the reporting controller stops receiving expected messages from module D, potentially leaving dependent systems without its battery data.
Common causes
Most likely first.
- Module unpowered
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
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
How to diagnose it
- Scan all modules and record freeze-frame and network codes to determine whether U014C is current and whether other controllers have also lost battery-module communication.
- Check the 12-volt battery condition and charging system, since low voltage can prevent the battery control module from waking or communicating.
- Inspect accessible low-voltage connectors and harnesses for Battery Energy Control Module D for damage, water intrusion, corrosion, or disturbed wiring; follow the vehicle's high-voltage safety instructions.
- Use the wiring diagram to check the module's specified low-voltage power and ground, including relevant fuses, before concluding the module has failed.
- Test the CAN circuit and gateway routing using the manufacturer's procedure, especially if several modules report communication faults.
- If power, ground, and network tests pass, check for module response and required configuration or programming with a compatible scan tool.
Common fixes
- Charge or replace a weak 12-volt battery and repair any charging fault.
- Repair a blown supply fuse or poor power or ground connection to module D.
- Repair damaged or corroded CAN wiring or connectors.
- Correct a gateway routing or configuration issue if confirmed by testing.
- Replace or reprogram Battery Energy Control Module D only after its supplies and network are verified.
Can I keep driving?
Because this fault concerns high-voltage battery management and may trigger reduced-power operation, avoid long trips and hard acceleration; stop if the vehicle warns of a battery or high-voltage fault or loses power. Arrange prompt diagnosis, since continued operation may be restricted or unavailable.
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.