A method for fault diagnosis and a computer device are provided. The method is applied to a battery management system of the energy storage system and includes the following. A first thermal-runaway parameter detected by a first detection apparatus and a second thermal-runaway parameter detected by a second detection apparatus are obtained. A difference between the first thermal-runaway parameter and the second thermal-runaway parameter is calculated. Determine that at least one of the first detection apparatus or the second detection apparatus fails, when the difference is greater than a difference threshold. Determine that a battery module fails, when the first thermal-runaway parameter is greater than a first threshold, the second thermal-runaway parameter is greater than a second threshold, and the difference is less than or equal to the difference threshold.