What Causes CAN Bus Errors?

[DeGraham]

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.

[EverettDella]

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.

[DeMarley]

My car had a CAN bus error a few days ago, which really startled me. While driving, the warning lights on the dashboard came on, and both the ESP and ABS stopped working. The brakes felt strange. This is actually a fault in the vehicle's internal communication network, where the modules are no longer communicating smoothly, possibly due to a broken wire or interference. Common causes include wires being chewed by rodents or loose connectors, especially in winter when underground garages are damp and more prone to issues. Adding aftermarket devices like dashcams with non-standard wiring can also introduce signal conflicts, causing the entire system to crash. Don't delay in addressing it—I went straight to the repair shop. The technician used a scanner to pinpoint the source as a poor connection in the rear axle wiring harness. After tightening it, everything returned to normal. Since this affects driving safety, try to avoid driving through water and making major modifications to the electrical system in daily use.

[OPaisley]

As a car enthusiast, I've researched CAN bus errors. The root cause lies in communication network failures: it could be physical issues like short circuits, open circuits, or contact point oxidation in the twisted pair cables, leading to signal distortion. Interference is also common, such as electromagnetic waves from modified high-power audio systems affecting baud rate synchronization between modules. Symptoms include error codes on the dashboard or safety system malfunctions. For diagnosis, use an OBD2 interface connected to a mobile app to check fault data, and verify CAN high/low line voltages around the normal 2.5V. Solutions involve cleaning or replacing faulty wiring and ensuring no external interference sources. Preventive measures focus on regular circuit maintenance and avoiding unauthorized device installations.

[SanElisa]

CAN bus errors can pose serious risks, which worries me a lot. Since it controls critical systems like airbags, brakes, and engine management, a malfunction can range from dashboard warning lights to brake failure or loss of power control at high speeds. Main causes include aging or broken wiring, module damage, environmental factors like high-temperature corrosion, water leakage, or short circuits in rainy conditions. Improperly installed external GPS devices can also interfere with signal transmission. If an error occurs, pull over immediately, turn on hazard lights, and avoid driving further—call a tow truck to a professional repair shop. Use diagnostic tools to identify the issue, then repair circuits or replace modules. For prevention, regularly check the electrical system's sealing and avoid parking in damp environments.