U0293
Lost Communication with Hybrid Vehicle Control System
The hybrid vehicle network has lost the hybrid control unit (HCU). The vehicle drops out of hybrid operation, often forced into a fail-safe mode that limits torque.
- 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.
- HCU unpoweredCommon
- HV interlock loop openedPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Hybrid Control Unit
- CAN Bus Wiring
U0293 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.