Repairing a CAN-Bus Harness

Always check manufacturer information for the correct procedures when repairing wiring. For a repair on a CAN-bus system, extreme caution must be taken. The CAN-bus system carries high-speed data information and is susceptible to communication errors if the repair is not completed according to the manufacturer’s recommendations. When measuring resistance or voltage on a CAN-bus, always use a digital multimeter and disconnect the negative battery terminal when measuring resistance.

CAN-bus wires are usually a twisted pair with terminating resistors to reduce noise and interferences. Use the correct-sized wires and terminals (if necessary) when making repairs. The challenge in repairing a twisted pair is that you need to perform the solder repair on wires that are twisted together. Simply put, trying to solder one wire back together when the other wire is very close to it is tough. Also, it is harder to use shrink tubing since the wires are twisted. It is possible to make these repairs; it just takes a bit of practice and patience. If both wires in the twisted pair need to be repaired, it is best to stagger the joints so that both joints are not side by side, which could lead to a short circuit. To prevent damage, ensure that all insulation is replaced and the harness is secured correctly. If using a soldering iron and solder to make repairs, use a rosin-core flux and clean the joint before insulating to finalize the repair. Heat-shrink tubing of the appropriate size ensures a sealed and insulated joint.