What Causes CAN Bus Errors?
2 Answers
Causes of CAN bus failures typically include the following: 1. Faults caused by the vehicle's power system; 2. Link failures in the vehicle's CAN bus system; 3. Node failures in the vehicle's CAN bus system. Below is an introduction to CAN: 1. CAN stands for Controller Area Network, developed by the German company BOSCH, known for its research and production of automotive electronic products. It eventually became an international standard (ISO11898) and is one of the most widely used field buses internationally. 2. The CAN bus in vehicles is used to achieve information channel sharing. It consists of a CAN controller, a transceiver, two data transmission terminals, and two data transmission buses.
I often encounter CAN bus errors when repairing cars, and this is no small issue. Essentially, it means the communication between the electronic modules in the car, like the brains, has been cut off. There can be many causes: aging wiring is prone to short circuits or poor contact—just think about those wires rubbing under the chassis, exposed to heat and moisture for years, with oxidized connectors that can't transmit signals properly. Interference is another common problem, such as when you install new devices like a reversing radar or audio system, but low-quality components can disrupt CAN signals, causing the modules to malfunction. Sometimes, the modules themselves fail, like the Engine Control Unit (ECU) or gateway, leading to communication breakdowns that make dashboard lights flicker or brake assist systems stop working. To diagnose, you need a scanner to read fault codes and check if the CAN-H and CAN-L line voltages are stable—if you don't have the tools, take it to a professional shop. Older cars are more prone to these issues, so it's advisable to inspect wiring harnesses for aging during regular maintenance.
