A CAN trace can show both wires shifting together while their difference remains recognisable. That points to a different question from a missing differential signal.

What to check next

For a warning that appears when a heavy electrical load operates, compare the network trace with the relevant module supply and ground under the same conditions. Ask whether the measuring reference moved too. Replacing a controller from one ground-referenced screenshot can leave the original connection problem untouched.

Useful information for an enquiry

Keep both channels, their reference points and the exact moment the load switched on.

A useful report separates the shared voltage movement from corruption of the actual message. Vehicle-specific limits and suitable measuring equipment still apply.

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 ringing after a harness joint or connector repair. Browse all vehicle-electronics diagnostic notes or return to the repair library.