Device for diagnosing malfunction in low speed controller area network in car, has comparison unit comparing underload voltage with minimal voltage and maximal voltage, and displaying units for signaling operating situation

摘要

The device (D) has connection units (MX1, MX2) respectively connected to electric wires (F1, F2) of a bus (BU) for accessing at voltages (V1, V2) on the wires. Processing units (MT1, MT2) constitute one of minimal voltage, maximal voltage and underload voltage from each voltage on the wire. A comparison unit compares the underload voltage with the minimal voltage and the maximal voltage so as to deliver a signal representing comparison result. Displaying units (MA1-MA4) are arranged for signaling operating situation represented by the delivered signal.