CAN controllers keep track of communication errors. As the error state worsens, a controller can become error-passive and, in the relevant transmit-error conditions, enter bus-off. Bus-off prevents that controller from continuing normal participation on the bus.
A missing module may have stopped transmitting
No communication can describe more than a missing power supply. The controller may be powered but unable to participate normally. A scan alone may not reveal which of these situations applies.
The investigation needs the network layout, affected controllers and electrical evidence. Keep the initial scan before cycling power or clearing faults. A controller that returns after a restart has provided useful information about the symptom, but the restart does not establish a lasting repair.
Find the condition causing the errors
Wiring, connections, timing or a faulty participant can require investigation depending on the system. The controller reporting bus-off is not automatically the component that created the underlying problem.
Tell AXION whether the fault affects one function or several at once, and whether it follows movement, moisture or temperature. Include any previous wiring changes. We can confirm the appropriate assessment route. Recovery behaviour is controller- and application-specific, so a generic instruction to force repeated reconnection should not replace diagnosis.
Arrange an assessment
For complex electrical and network diagnostics, send the vehicle details and fault report to AXION. We support enquiries from drivers and garages. Workshop, postal and remote options depend on the job and are confirmed before booking.
Technical reference
Read the supporting technical documentation. The referenced design or vehicle application defines its scope; it is not a universal repair procedure.
Related reading
A CAN acknowledgement does not prove the requested function worked. Browse the automotive electronics repair library for other systems and symptoms.