Gm Global Technolgoy Operations, Inc.

David Gumpert

Xinyu Du

Shengbing Jiang

Atul Nagose

Rod Niner

Aaron B Bloom

Dongyi Zhou

Aaron D Motyl

A system includes control modules, a low-voltage communications bus, e.g., a CAN bus of a vehicle, a voltage sensor that measures a bus voltage and outputs 2.5-3.5 VDC high-data and 1.5-2.5 VDC low-data, and a host electronic control unit (ECU). The host ECU detects a recoverable fault using a data pattern in the bus voltage data when the data is outside of a calibrated range, and recalibrates the sensor. Recalibration may be by adjustment to a scaling factor and/or a bias value. Non-recoverable 'stuck-at-fault'-type or 'out-of-range'-type faults may be detected using the pattern, as may be a ground offset fault. A method includes measuring the bus voltage using the sensor, comparing the output data to a range to detect the fault, and isolating a sensor fault as a recoverable fault using the data pattern when the data is outside of the range. The sensor is then be recalibrated.

Analog-to-digital fault detection, isolation, and mitigation for a low-voltage communications network

A method is disclosed for detecting ground faults in a communications system. The method includes measuring a predetermined number of voltage points; determining if the measured voltage points represent recessive or dominant bits; identifying which of the predetermined number of voltage points represent inter-frame bits and which represent frame data bits based on whether the measured voltage points are recessive or dominant; calculating a maximum average voltage for the inter-frame bits; calculating an average frame voltage for all dominant bits within a frame; determining a high average dominant voltage count based on a number of frames for which the average frame voltage is greater than a high voltage threshold; and determining if a ground fault exists based on the average frame voltage and the high average dominant voltage count.

Detection of ECU ground fault with can bus voltage measurements

Disclosed herein are a system and a related computer-executed method of locating a source of a ground offset in a network of electronic devices interconnected by a communication bus. An exemplary method detects signal voltages on the communication bus that are indicative of a ground offset condition, and saves voltage timestamps for the detected signal voltages such that each detected signal voltage has a respective voltage timestamp. Message timestamps are added to messages on the communication bus, such that each message has a respective message timestamp. The message timestamps are compared against the voltage timestamps to identify at least one of the electronic devices as a ground offset source.

Determining the source of a ground offset in a controller area network

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Farmington Hills, MI, United States of America

David Gumpert