What are the common electrical faults of J1939 cable?

J1939 cable in automobiles is an important data transmission line in automotive electronic control systems. Common electrical performance faults mainly include the following:

Open circuit

Fault description: The wire inside the cable is disconnected, causing the signal to be unable to transmit normally, resulting in communication failure or abnormal communication between related automotive electronic control units (ECUs).

Reason for occurrence: It may be due to excessive stretching, bending, or compression of the cable during installation, resulting in the breakage of the metal wire inside the wire; It may also be due to long-term use, cable aging and wear, causing the wires to gradually disconnect; In addition, the vibration and bumps of the vehicle may also cause the connection points inside the cable to loosen or fall off, resulting in a circuit break.

short circuit

Fault description: The insulation layer between different wires inside the cable is damaged, causing current to form a path between wires that should not be conducting, interfering with normal signal transmission and potentially causing misoperation or malfunction of the automotive electronic system.

Causes: Usually due to damage to the insulation layer of the cable, such as scratches from sharp objects, melting at high temperatures, or aging or deterioration of the insulation material, resulting in loss of insulation performance. In addition, accidents such as collision and compression of vehicles may also cause damage to the insulation layer of cables, resulting in short circuits.

poor contact

Fault description: The connection points between the cable and the connector, as well as between the connector and the ECU, have become loose, oxidized, or corroded, resulting in increased contact resistance, unstable signal transmission, and occasional data errors.

Cause: The connector was not securely inserted or fixed during installation, and the vehicle vibration caused the connection point to loosen; Long term exposure to moisture, dust, and other environments can cause oxidation and corrosion of connector pins, affecting contact performance; In addition, frequent plugging and unplugging of connectors may also lead to pin wear and poor contact.

electromagnetic interference 

Fault description: The electromagnetic waves generated by external electromagnetic interference sources affect the signals transmitted in J1939 cables, resulting in signal distortion and an increase in error rate, which affects the normal operation of automotive electronic systems.

Cause: The engine, ignition system, motor and other equipment in the car will generate strong electromagnetic radiation during operation. If the J1939 cable does not have good shielding measures or is too close to these interference sources, it is easy to be affected by electromagnetic interference. In addition, nearby radio transmission equipment, high-voltage power lines, etc. may also become sources of electromagnetic interference.