Incident: Faulty Shift Cable Bushing Causes Rollaway Risk in Fiat 500

Published Date: 2019-11-27

Postmortem Analysis
Timeline 1. The software failure incident involving the faulty shift cable bushing in the Fiat 500 models happened in November 2019 as per the article [92563].
System 1. Faulty shift cable bushing in 2012-2013 Fiat 500 models with six-speed automatic transmission [Article 92563]
Responsible Organization 1. The software failure incident in the Fiat 500 models was caused by a faulty shift cable bushing, as described in the documents filed by Fiat Chrysler with the National Highway Traffic Safety Administration [Article 92563].
Impacted Organization 1. Owners of the affected Fiat 500 models [Article 92563]
Software Causes 1. The software failure incident in the Fiat 500 models was caused by a faulty shift cable bushing that deteriorates over time, leading to the transmission not shifting into the gear selected by the driver [92563].
Non-software Causes 1. The faulty shift cable bushing was identified as the cause of the problem, leading to the shifter cable detaching from the transmission and affecting the gear selection [Article 92563].
Impacts 1. The software failure incident led to a rollaway risk for 51,788 Fiat 500 models with six-speed automatic transmission due to a faulty shift cable bushing [92563]. 2. The transmission may not shift into the gear selected by the driver, potentially causing the car to be in a different gear than intended, increasing the risk of accidents and injuries [92563]. 3. The incident resulted in three "minor accidents" potentially related to the issue, although no injuries were reported [92563].
Preventions 1. Implementing rigorous software testing procedures during the development phase to detect any potential issues related to the shift cable bushing and transmission control software [92563]. 2. Conducting regular maintenance checks and inspections on the shift cable bushing and transmission control software to identify any signs of deterioration or malfunction before it leads to a critical failure [92563]. 3. Enhancing the design of the shift cable bushing to improve its durability and longevity, thereby reducing the likelihood of detachment and transmission control software errors [92563].
Fixes 1. A technician will replace the shifter cable adjuster to resolve the problem [Article 92563].
References 1. Fiat Chrysler (FCA) [Article 92563]

Software Taxonomy of Faults

Category Option Rationale
Recurring unknown The article does not mention any software failure incident happening again at the same organization or at multiple organizations. Therefore, the information related to the software failure incident in the article is unknown.
Phase (Design/Operation) design (a) The software failure incident in this case is related to the design phase. The article mentions a faulty shift cable bushing as the cause of the problem in the Fiat 500 models. This issue was introduced during the development of the system, specifically in the design of the shift cable bushing, which deteriorates over time and leads to the transmission not shifting into the selected gear by the driver. This design flaw poses a risk of the car rolling away and increases the chance of injury and a crash [Article 92563].
Boundary (Internal/External) within_system (a) within_system: The software failure incident described in the article is related to a faulty shift cable bushing causing the transmission to not shift into the gear the driver selects. This issue originates from within the system of the Fiat 500 models, specifically the transmission system [92563]. (b) outside_system: There is no 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 faulty shift cable bushing causing the transmission to not shift into the selected gear, potentially leading to a rollaway risk [Article 92563]. (b) The failure in this incident is due to a faulty shift cable bushing, a component issue introduced during the manufacturing process or due to wear and tear over time, which is a contributing factor introduced by human actions (design, production, maintenance) [Article 92563].
Dimension (Hardware/Software) hardware (a) The software failure incident in this case is not directly related to hardware but rather to a faulty shift cable bushing that causes the transmission to not shift into the selected gear properly. The issue originates from the deterioration of the bushing over time, leading to the transmission not engaging the correct gear selected by the driver. This issue is more related to a mechanical or design flaw rather than a hardware failure [92563]. (b) The software failure incident is not directly attributed to software issues in this case. The problem is specifically described as a faulty shift cable bushing causing the transmission to malfunction, rather than any software-related bugs or faults. The article does not mention any software contributing factors to the failure incident [92563].
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident described in the article is non-malicious. The issue with the Fiat 500 models is attributed to a faulty shift cable bushing that deteriorates over time, causing the transmission to not shift into the gear selected by the driver. This can lead to the car not being in the intended gear, increasing the risk of a rollaway and potential accidents [Article 92563].
Intent (Poor/Accidental Decisions) unknown The software failure incident described in the article [92563] is not related to poor decisions or accidental decisions. Instead, it is attributed to a faulty shift cable bushing causing a rollaway risk in Fiat 500 models.
Capability (Incompetence/Accidental) accidental (a) The software failure incident in this case is not related to development incompetence but rather to a faulty shift cable bushing causing the transmission to not shift into the selected gear, potentially leading to a rollaway risk [Article 92563]. (b) The software failure incident in this case is more aligned with an accidental failure caused by the deterioration of the bushing over time, leading to the detachment of the shifter cable from the transmission [Article 92563].
Duration temporary The software failure incident described in the article is related to a faulty shift cable bushing in 2012-2013 Fiat 500 models with six-speed automatic transmission [Article 92563]. This issue causes the transmission to not shift into the gear the driver selects, leading to a risk of the car rolling away and potential accidents. The article does not specifically mention whether this software failure incident is permanent or temporary.
Behaviour other (a) crash: The software failure incident described in the article does not involve a crash where the system loses state and does not perform any of its intended functions. The issue is related to a faulty shift cable bushing causing the transmission to not shift into the gear the driver selects, potentially leading to the car rolling away [Article 92563]. (b) omission: The software failure incident is not due to the system omitting to perform its intended functions at an instance(s). The issue is specifically related to the transmission not shifting correctly due to a faulty part [Article 92563]. (c) timing: The software failure incident is not due to the system performing its intended functions correctly, but too late or too early. The issue is related to a mechanical fault in the shift cable bushing causing incorrect gear selection [Article 92563]. (d) value: The software failure incident is not due to the system performing its intended functions incorrectly. The issue is not related to the software itself but rather to a faulty mechanical component causing incorrect gear selection in the transmission [Article 92563]. (e) byzantine: The software failure incident is not due to the system behaving erroneously with inconsistent responses and interactions. The issue is related to a specific mechanical fault in the shift cable bushing affecting gear selection in the transmission [Article 92563]. (f) other: The behavior of the software failure incident is related to a mechanical issue with the shift cable bushing causing the transmission to not shift into the correct gear selected by the driver, potentially leading to a rollaway risk and safety concerns [Article 92563].

IoT System Layer

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

Other Details

Category Option Rationale
Consequence harm, theoretical_consequence The consequence of the software failure incident described in the article is related to potential harm to individuals due to the faulty shift cable bushing in the Fiat 500 models. The article mentions that if the transmission does not shift into the gear the driver selects, there is a risk of the car rolling away, leading to an increased risk of injury and a crash. Although there were three "minor accidents" potentially related to this issue, fortunately, there were no reported injuries [Article 92563].
Domain transportation, manufacturing The software failure incident reported in Article 92563 is related to the transportation industry. The article discusses a rollaway risk in a group of Fiat 500 models due to a faulty shift cable bushing, which affects the transmission of the vehicles. This issue poses a safety risk as the transmission may not shift into the gear selected by the driver, potentially leading to the car rolling away and an increased risk of injury and crashes [92563]. The recall and fix for this issue are specific to the affected Fiat 500 models, which are vehicles designed for transportation purposes.

Sources

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