Some single-pair Ethernet links require complementary roles at their two ends. A configuration mismatch can prevent the link forming.

Interpreting the evidence

After a controller or board repair, verify the supported hardware variant and configuration before treating the cable as the only suspect. Compare the identity of both link partners. Keep any component substitutions or prior setup changes visible in the repair record.

Keep this evidence

Supply both module references and the exact link-status report.

Role settings are design-specific. Do not experiment with undocumented configuration changes on a vehicle or assume an industrial Ethernet example applies directly.

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 — Ethernet cable-distance estimates from a diagnostic test. Browse all vehicle-electronics diagnostic notes or return to the repair library.