U0289 indicates that the vehicle's main control network has lost communication with the DC-AC converter control module designated 'B'. This module manages the inverter that converts high-voltage DC from the hybrid/EV battery to AC for the motor-generator(s). The code sets when the module stops responding on the CAN bus for a calibrated period.
Chafing, rodent damage, water intrusion, or corrosion on the power, ground, or CAN communication wires between the module and the vehicle bus.
Poor contact at the module's connector pins — especially the CAN high/low, battery voltage, or ground circuits — interrupts communication.
The module's internal transceiver, processor, or power supply has failed, preventing it from transmitting or receiving on the bus.
A short to voltage/ground on CAN high or low, an open circuit, or a missing termination resistor elsewhere on the bus can isolate module B.
Blown fuse, open circuit, or high resistance in the module's dedicated ignition-switched or constant power feed or its ground path.
Rare; the gateway or vehicle control unit's CAN controller has failed, but this typically sets multiple U-codes simultaneously.
Almost never. U0289 is a loss-of-communication code pointing to the DC-AC converter control module B or its wiring. The PCM/VCU is only the recipient of the missing message; replacing it does not restore the module's ability to communicate.
Indirectly. Low system voltage can cause modules to reset or drop off the bus, but the root cause is still the voltage issue — not the module itself. Verify charging system health before condemning the converter module.
No. The hybrid/EV propulsion system will likely be disabled or severely limited. The vehicle may not enter ready mode or may shut down while driving.
Some vehicles use multiple DC-AC converter control modules (e.g., one per motor-generator or per axle). 'B' identifies the specific module that has stopped communicating.