What is the CAN Bus Repair Method?
3 Answers
CAN bus repair methods are: 1. Check specific fault symptoms; 2. Use relevant diagnostic instruments for diagnosis; 3. Formulate relevant maintenance plans; 4. Locate specific fault locations and causes; 5. Combine corresponding detection methods and measurement results to find the fault point and eliminate the fault. Symptoms of CAN bus failure: 1. Abnormal dashboard display; 2. Vehicle cannot start; 3. Decreased power performance; 4. Unable to turn off after starting; 5. Some electronic control system functions fail. Characteristics of CAN bus: 1. High performance; 2. High integration; 3. Controllability; 4. Verification and error correction; 5. Repair capability; 6. Intelligence; 7. Security.
As an experienced auto mechanic, I've seen countless CAN bus failures in the workshop. When vehicle dashboards display random error codes, it's likely a CAN network issue. For repairs, first scan with a professional diagnostic tool to identify which node is offline. Then inspect the wiring harness: check for physical damage, wear, or rodent bites; verify if connectors are loose or corroded. Use a multimeter to measure voltage: normal differential pressure between CAN-H and CAN-L lines should be around 2.5V - too high or low may indicate short circuits or breaks. Sometimes the terminal resistor fails and needs replacement with a 120-ohm one. Also, ECU module failure is a common cause - always test by isolating sections before replacement. After completion, reprogram and reset the system. Never cut corners with bus repairs - negligence can cause engine stalls or brake failures. The golden rule: don't experiment blindly; if unsure, send it to a professional shop.
As an enthusiast who frequently tinkers with my own car, working on the CAN bus isn't difficult. First, purchase an OBD-II scanner to read the fault codes. If it reports network communication issues, further investigation is needed. Open the engine compartment to check for damaged or loose wiring harnesses. The terminating resistor is located at the end of the module—measure it to ensure it's around 120 ohms. A simple DIY method is to use a multimeter to test CAN line voltage: the standard value should be 2.5V when the ignition is on; significant deviations indicate serious problems. Disconnect sensor nodes step by step to identify which section affects bus recovery. Once the damaged point is found, replace the wiring or module. Don’t forget to restart the power supply to test the results. After repairs, regularly clean the wiring harness to prevent aging. If your hands-on skills are weak, stop—electrical systems are prone to chain damage. It’s recommended to use diagnostic tools frequently to avoid missed inspections.
