Some CAN transceivers limit how long a dominant transmit request can hold the bus. Protection can therefore change the observed waveform.

How to narrow it down

When a module appears to transmit briefly and then becomes quiet, compare the transmit request, bus response and supply history. Establish whether the behaviour is repeatable or follows a reset. A technician needs to separate a protection response from a broken wire or missing message request.

What to include with the fault report

Save a recording that includes the beginning of the event, not only the quiet period afterwards.

The exact device specification determines the protection behaviour. Do not bypass a protection feature to keep a suspect controller transmitting.

Speak to AXION

For CAN-bus and vehicle-network diagnostics, send your vehicle details and fault report. Workshop assessment is in Didcot, Oxfordshire. Suitable postal or remote work is confirmed before booking.

Technical background from NXP. The referenced design explains the principle; the vehicle-specific procedure determines the repair.