What it means
ECU lost CAN communication with battery energy control module C (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 C monitors part of the high-voltage battery system in a hybrid or electric vehicle and communicates its information over CAN. This code sets when the reporting module cannot receive expected messages from that battery module; loss of module power, incorrect message routing through a gateway, a CAN wiring fault, or a termination problem may be involved.
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
- Check the vehicle's warnings and scan all modules with a tool capable of reading hybrid or EV systems, saving freeze-frame data and related battery, gateway, and CAN codes.
- Check the 12-volt battery condition and charging system, since low 12-volt supply can prevent battery control modules or gateways from communicating.
- Use the scan tool to see whether battery energy control module C is reachable and whether the other battery control modules and gateway are reporting normally.
- Inspect accessible low-voltage connectors and CAN wiring for the named module and gateway for looseness, corrosion, water entry, or damage; do not open or probe high-voltage components.
- Have the module's low-voltage power and ground and the relevant CAN path checked against the manufacturer's procedure and specifications.
- If the wiring and supplies are sound, have the manufacturer's diagnostic procedure used to assess module communication, gateway routing, and CAN termination before replacing components.
Common fixes
- Charge or replace a weak 12-volt battery and correct a charging-system fault.
- Reconnect or repair a damaged low-voltage connector or CAN wiring connection.
- Repair a module power or ground fault confirmed by testing.
- Correct a gateway routing or CAN termination fault identified by the manufacturer's diagnostic procedure.
- Replace or configure battery energy control module C only after the cause is confirmed.
Can I keep driving?
This fault can trigger warning lights, power limitation, or shutdown of hybrid or EV functions. Do not drive if the vehicle shows a stop or high-voltage system warning, loses drive power, or behaves abnormally; arrange diagnosis by a technician equipped for high-voltage vehicles.
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.