The labels CAN High and CAN Low identify signals in a particular network arrangement. They do not mean that one wire should simply be treated as a conventional power feed and the other as earth. Start with the correct wiring diagram and network type.
Read measurements in context
A voltage value needs its reference point, operating state and measurement method. An average from a multimeter and a captured waveform answer different questions. Do not apply a remembered number from another vehicle as a universal pass-or-fail rule.
Identify the affected section
Modern vehicles can contain several networks connected through gateways. The diagnostic connector is not necessarily a direct view of every network segment. The assessor needs to know where the measurement was made and which controllers are affected.
For a garage referral, include labelled traces where available, tool settings and the current communication map. NXP’s network portfolio illustrates the range of vehicle network technologies. AXION can discuss the appropriate next assessment using vehicle-specific information. Do not bridge unidentified data wires or apply external voltage to them as an improvised communication test.
Related help
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Browse all fault guides or use the vehicle module finder to prepare your enquiry. Send your vehicle details, what has gone wrong and any scan or test results. Contact us before booking or posting a module so we can check whether we can help.