A receiver can control how many consecutive frames are sent before another flow-control exchange. A pause at a block boundary may therefore be part of the configured transfer.

Interpreting the evidence

Compare the pauses with the flow-control messages and timestamps in the same recording. If progress stops at a boundary, check whether the next permission arrived and whether the receiver was still active. This is different from random loss of communication.

Keep this evidence

Send the complete transfer trace rather than a cropped section containing only the pause.

Block-size settings belong to the supported transport configuration. Changing them blindly can hide a timing problem or create another one.

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 python-can-isotp. The referenced design explains the principle; the vehicle-specific procedure determines the repair.