Incident: Subaru Ascent Recall Due to Fire Risk from Wiring Defect

Published Date: 2022-12-13

Postmortem Analysis
Timeline 1. The software failure incident of the Subaru Ascent vehicles due to a wiring connection defect causing fire risks happened in 2022 [137658].
System 1. Heater ground bolts and wiring connection in Subaru Ascent sport utility vehicles with model years between 2019 to 2022 [137658].
Responsible Organization 1. The software failure incident in the Subaru Ascent vehicles was caused by a production-related defect in a wiring connection that could lead to a fire while the heater is in operation [137658].
Impacted Organization 1. Owners of Subaru Ascent sport utility vehicles with model years between 2019 to 2022 were impacted by the software failure incident, as they were advised to park their vehicles outside until repairs are completed [137658].
Software Causes 1. The software causes of the failure incident were not explicitly mentioned in the article [137658]. Therefore, the specific software causes of the failure incident are unknown.
Non-software Causes 1. Production-related defect in the wiring connection causing a fire risk due to excessive heat [137658] 2. Defective heater ground bolts and ground wire connector holder [137658]
Impacts 1. Increased fire risks in 271,000 Subaru Ascent sport utility vehicles with model years between 2019 to 2022 [137658]. 2. Two fires reported in the affected vehicles [137658]. 3. No injuries or crashes reported as a result of the software failure incident [137658]. 4. Owners urged to park their vehicles outside until repairs are completed to mitigate the fire risk [137658].
Preventions 1. Implementing thorough quality control checks during the production process to detect and rectify any wiring connection defects before the vehicles are released to the market [137658]. 2. Conducting more extensive testing and monitoring of the vehicles post-production to identify any potential issues related to the heater operation and wiring connections [137658]. 3. Utilizing advanced technology and tools for production processes to ensure the proper assembly and functioning of components, such as the heater ground bolts and wiring connections, to prevent fire risks [137658].
Fixes 1. Subaru dealers will replace heater ground bolts and, if needed, replace the ground wire and the connector holder to fix the software failure incident [137658].
References 1. Subaru (9778.T) [137658] 2. National Highway Traffic Safety Administration [137658]

Software Taxonomy of Faults

Category Option Rationale
Recurring unknown The article does not mention any software failure incident related to either one_organization or multiple_organization. Therefore, the information about the software failure incident happening again at the same organization or at multiple organizations is unknown.
Phase (Design/Operation) design (a) The software failure incident in this case seems to be related to the design phase. The article mentions that Subaru identified a production-related defect in the wiring connection that can cause a fire while the heater is in operation due to excessive heat, leading to melting of the ground terminal and surrounding components. This defect was introduced during the production process, indicating a failure in the design or manufacturing phase [137658]. (b) There is no specific information in the article pointing to the software failure incident being related to the operation phase or misuse of the system.
Boundary (Internal/External) within_system (a) within_system: The software failure incident in the Subaru vehicles was due to a production-related defect in a wiring connection that could cause a fire while the heater is in operation. This defect was identified as a result of a change in the production line tools in early 2020, where air tools were introduced to replace a battery tool. The issue was corrected in production on April 29, 2022, with an updated tightening tool to prevent incomplete tightening, as reported by Reuters [137658]. (b) outside_system: There is no specific mention in the article of the software failure incident being caused by contributing factors originating from outside the system.
Nature (Human/Non-human) non-human_actions, human_actions (a) The software failure incident in this case is not related to non-human actions but rather to a production-related defect in the wiring connection that can cause a fire while the heater is in operation. This defect was identified as a contributing factor to the increased fire risks in Subaru Ascent sport utility vehicles [137658]. (b) Human actions were involved in addressing the software failure incident as Subaru took action to correct the issue in production by introducing an updated tightening tool on April 29, 2022, to prevent incomplete tightening. Additionally, Subaru decided to conduct a voluntary safety recall out of an abundance of caution, indicating a human-initiated response to the software failure incident [137658].
Dimension (Hardware/Software) hardware (a) The software failure incident in the Subaru recall was not directly related to software issues but rather to a hardware defect. The article mentions that the recall was due to a wiring connection with a production-related defect that could cause a fire while the heater is in operation [137658]. This indicates that the root cause of the failure was a hardware issue in the wiring connection, not a software-related problem.
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident in this case is non-malicious. The failure was attributed to a production-related defect in a wiring connection that could cause a fire while the heater is in operation due to excessive heat, leading to melting of the ground terminal and surrounding components. Subaru mentioned that the issue was corrected in production on April 29, 2022, with an updated tightening tool to prevent incomplete tightening, indicating a non-malicious intent to address the problem [137658].
Intent (Poor/Accidental Decisions) unknown The software failure incident reported in Article 137658 regarding the Subaru recall does not directly mention any software-related issues or failures. Therefore, it is unknown whether the incident was due to poor decisions or accidental decisions.
Capability (Incompetence/Accidental) unknown Unknown
Duration unknown The articles do not mention any software failure incident related to the Subaru recall of 271,000 Ascent sport utility vehicles due to fire risks. Therefore, the duration of the software failure incident in this case is unknown.
Behaviour other (a) crash: The software failure incident in the Subaru vehicles was not described as a crash where the system loses state and does not perform any of its intended functions [137658]. (b) omission: The software failure incident did not involve the system omitting to perform its intended functions at an instance(s) [137658]. (c) timing: The software failure incident was not related to the system performing its intended functions correctly but too late or too early [137658]. (d) value: The software failure incident was not due to the system performing its intended functions incorrectly [137658]. (e) byzantine: The software failure incident did not involve the system behaving erroneously with inconsistent responses and interactions [137658]. (f) other: The software failure incident in the Subaru vehicles was related to a wiring connection defect that could cause a fire while the heater is in operation due to excessive heat, leading to melting of components. This behavior does not fit into the options provided [137658].

IoT System Layer

Layer Option Rationale
Perception None None
Communication None None
Application None None

Other Details

Category Option Rationale
Consequence property The consequence of the software failure incident reported in Article 137658 is related to property. The software failure in Subaru's Ascent sport utility vehicles led to a defect in a wiring connection that could cause a fire while the heater is in operation, potentially resulting in damage to the vehicle [137658].
Domain manufacturing The software failure incident reported in the article is related to the manufacturing industry. Subaru announced a recall of 271,000 Ascent sport utility vehicles due to a production-related defect in a wiring connection that can cause a fire while the heater is in operation [137658]. The defect in the wiring connection poses a fire risk, indicating that the software failure incident is associated with the manufacturing industry.

Sources

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