A branch added to a CAN network changes its physical arrangement. Diagnostic leads can become part of the fault being measured.

How to narrow it down

If a communication problem appears only with a particular test setup, document the adapter chain and compare with the approved direct connection. Keep the same vehicle state for both recordings. Avoid interpreting a workshop-only failure as proof that the customer’s original module has failed.

What to include with the fault report

List each extension, breakout adapter and interface, including any built-in termination.

The comparison should be planned by the technician. Do not unplug live safety controllers or improvise a network connection while the vehicle is in use.

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 Texas Instruments. The referenced design explains the principle; the vehicle-specific procedure determines the repair.

Related reading — CAN High and CAN Low swapped after connector replacement. Browse all vehicle-electronics diagnostic notes or return to the repair library.