Incident: Subaru Engine Control Module and PCV Valve Recalls.

Published Date: 2019-10-25

Postmortem Analysis
Timeline 1. The software failure incident involving the buggy engine control module and the separating positive crankcase ventilation (PCV) valve in Subaru Crosstrek and Impreza models happened in 2018-2019 and 2017-2018 respectively [91424]. 2. The article was published on 2019-10-25. 3. Estimated timeline: - The incident involving the buggy engine control module occurred in 2018-2019, so it likely happened in 2018 or 2019. - The incident involving the separating PCV valve occurred in 2017-2018, so it likely happened in 2017 or 2018. Therefore, the software failure incidents happened in 2018 and 2017 respectively.
System 1. Engine Control Module (ECM) in 2018-2019 Subaru Crosstrek vehicles and 2017-2019 Impreza models [Article 91424] 2. Positive Crankcase Ventilation (PCV) valve in 2018 Subaru Crosstrek and 2017-2018 Impreza models [Article 91424]
Responsible Organization 1. The software failure incident in the Subaru Crosstrek and Impreza models was caused by a buggy engine control module (ECM) [Article 91424]. 2. The incident was also attributed to a separating positive crankcase ventilation (PCV) valve, which could dump debris into the engine [Article 91424].
Impacted Organization 1. Owners of 2018-2019 Subaru Crosstrek and 2017-2019 Impreza models were impacted by the software failure incidents mentioned in the article [91424].
Software Causes 1. The failure incident was caused by a buggy engine control module (ECM) software that continued to power the ignition coil after the driver shut the vehicle off, leading to a short circuit and blown fuse [Article 91424]. 2. The software issue also involved a separating positive crankcase ventilation (PCV) valve that could dump debris into the engine, causing engine oil to enter the combustion chamber and potentially leading to a loss of power while driving [Article 91424].
Non-software Causes 1. Buggy engine control module leading to a short circuit and blown fuse [Article 91424] 2. Separating positive crankcase ventilation (PCV) valve dumping debris into the engine, causing engine oil to enter the combustion chamber and potential loss of power [Article 91424]
Impacts 1. The software failure incident involving a buggy engine control module in Subaru Crosstrek and Impreza models led to the risk of a short circuit occurring while driving, potentially causing the driver to suddenly lose power and the engine not restarting immediately, thereby increasing the risk of a crash [91424]. 2. The incident also resulted in irregular vibrations and cylinder misfires while the engine runs, serving as warning signs for the problem [91424].
Preventions 1. Implementing thorough testing procedures during the software development phase to detect and address bugs in the engine control module and positive crankcase ventilation (PCV) valve software [91424]. 2. Conducting regular software quality assurance checks to ensure that the ECM software functions correctly and does not have any issues that could lead to a short circuit or power loss [91424]. 3. Implementing a robust software update mechanism to allow for timely distribution of updated ECM software to fix any identified issues [91424]. 4. Enhancing monitoring capabilities to detect anomalies in the software behavior, such as irregular vibrations and cylinder misfires, which could indicate potential issues with the ECM [91424].
Fixes 1. Updated ECM software will fix the problem related to the buggy engine control module in the Subaru Crosstrek and Impreza models [Article 91424]. 2. Technicians will inspect the ignition coil and replace it if necessary to address the issue [Article 91424].
References 1. Documents filed with the National Highway Traffic Safety Administration [91424]

Software Taxonomy of Faults

Category Option Rationale
Recurring one_organization (a) The software failure incident related to the buggy engine control module affecting 2018-2019 Crosstrek vehicles and 2017-2019 Impreza models has led to a recall by Subaru. This issue involves the ECM continuing to power the ignition coil after the driver shuts the vehicle off, potentially causing a short circuit and a blown fuse [91424]. (b) The software failure incident related to a separating positive crankcase ventilation (PCV) valve affecting 2018 Crosstrek and 2017-2018 Impreza models has also led to a recall by Subaru. This issue involves the PCV valve separating and dumping debris into the engine, potentially leading to engine oil entering the combustion chamber and causing power loss [91424].
Phase (Design/Operation) design, operation (a) The software failure incident related to the design phase can be seen in the article where it mentions a buggy engine control module (ECM) affecting 2018-2019 Crosstrek vehicles and 2017-2019 Impreza models. The ECM issue causes the ignition coil to remain powered even after the driver shuts off the vehicle, potentially leading to a short circuit and blown fuse, which can result in power loss while driving and the engine not restarting immediately [91424]. (b) The software failure incident related to the operation phase can be observed in the article discussing a separating positive crankcase ventilation (PCV) valve issue affecting 2018 Crosstrek and 2017-2018 Impreza models. If the PCV valve separates, it can allow engine oil into the combustion chamber, leading to increased exhaust fumes and potential loss of power while driving, increasing the risk of a crash [91424].
Boundary (Internal/External) within_system (a) The software failure incident related to the Subaru recalls falls under the within_system boundary. The issues mentioned in the articles are related to a buggy engine control module (ECM) and a separating positive crankcase ventilation (PCV) valve, both of which are internal components of the vehicles' systems that have caused the failures [91424].
Nature (Human/Non-human) non-human_actions (a) The software failure incident related to non-human actions in the articles is the buggy engine control module issue affecting 2018-2019 Crosstrek vehicles and 2017-2019 Impreza models. The ECM may continue to power the ignition coil after the driver shuts the vehicle off, leading to a short circuit and a blown fuse. This issue can cause irregular vibrations and cylinder misfires while the engine runs, potentially resulting in a sudden loss of power while driving, increasing the risk of a crash [91424].
Dimension (Hardware/Software) hardware (a) The software failure incident related to hardware: - The first recall mentioned in the article [91424] is due to a buggy engine control module (ECM) that may continue to power the ignition coil after the driver shuts the vehicle off, potentially leading to a short circuit and a blown fuse. This issue originates in the hardware component of the ECM. - The second recall involves a separating positive crankcase ventilation (PCV) valve that could dump debris into the engine, leading to engine oil entering the combustion chamber. This issue also originates in the hardware component of the PCV valve. (b) The software failure incident related to software: - The article does not specifically mention any software-related failures or issues.
Objective (Malicious/Non-malicious) non-malicious The software failure incident described in the article does not involve any malicious intent. Both recalls mentioned in the article are related to hardware issues - a buggy engine control module and a separating positive crankcase ventilation (PCV) valve. These issues are not caused by any malicious software or actions but rather by defects in the components themselves. Therefore, the software failure incident is categorized as non-malicious [91424].
Intent (Poor/Accidental Decisions) unknown The software failure incident described in the article does not directly relate to poor or accidental decisions. Instead, it focuses on technical issues with the engine control module (ECM) and positive crankcase ventilation (PCV) valve in Subaru vehicles, leading to potential safety risks and the need for recalls and repairs [91424].
Capability (Incompetence/Accidental) development_incompetence (a) The software failure incident related to development incompetence in the articles is the buggy engine control module issue affecting 2018-2019 Crosstrek vehicles and 2017-2019 Impreza models. The ECM may continue to power the ignition coil after the driver shuts the vehicle off, leading to a short circuit and a blown fuse, potentially causing the driver to suddenly lose power and the engine not restarting immediately, increasing the risk of a crash [91424]. This issue highlights a failure in the development process that led to a critical software bug affecting a large number of vehicles. (b) The software failure incident related to an accidental issue in the articles is the separating positive crankcase ventilation (PCV) valve problem affecting 2018 Crosstrek and 2017-2018 Impreza models. If the PCV valve separates, it can invite engine oil into the combustion chamber, leading to increased exhaust fumes and potential loss of power, increasing the risk of a crash [91424]. This issue appears to be more of a mechanical failure rather than a direct software bug, possibly caused by a design flaw or manufacturing defect.
Duration unknown The articles do not mention any software failure incident related to the duration of the failure being permanent or temporary. Therefore, the duration of the software failure incident in this case is unknown.
Behaviour crash, omission, value, other (a) crash: The article mentions a scenario where the driver may suddenly lose power and the engine may not restart immediately due to the software issue. This situation increases the risk of a crash [91424]. (b) omission: The software issue with the engine control module may lead to a short circuit and a blown fuse, causing the engine to lose power. This omission of performing its intended function can result in irregular vibrations and cylinder misfires while the engine runs [91424]. (c) timing: The article does not specifically mention any failures related to timing issues. (d) value: The software issue with the engine control module can cause the ECM to continue to power the ignition coil after the driver shuts the vehicle off, leading to a short circuit and a blown fuse. This incorrect behavior of the software can result in the engine not functioning as intended [91424]. (e) byzantine: The article does not mention any failures related to byzantine behavior. (f) other: The software issue with the engine control module and the positive crankcase ventilation (PCV) valve can lead to the system behaving in unexpected ways, such as inviting engine oil into the combustion chamber and dumping debris into the engine, which are not explicitly covered by the options (a) to (e) [91424].

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 related to the Subaru recalls mentioned in Article 91424 is primarily categorized under option (d) property. The software failure in this case led to potential property damage as a result of the engine issues in the Subaru Crosstrek and Impreza models. The faulty engine control module and the separating positive crankcase ventilation (PCV) valve could cause damage to the vehicles, potentially resulting in the loss of power while driving, which increases the risk of a crash [91424]. The article mentions that the repairs and work to address these software-related issues will be free of charge for the owners, indicating that the consequences were more related to potential property damage rather than physical harm or fatalities.
Domain transportation, manufacturing (a) The software failure incident reported in Article 91424 is related to the transportation industry. The article discusses recalls for Subaru Crosstrek and Impreza models due to engine issues, specifically related to a buggy engine control module and a separating positive crankcase ventilation (PCV) valve. These issues could lead to sudden power loss while driving, increasing the risk of a crash, which directly impacts the transportation of people using these vehicles [91424].

Sources

Back to List