Overview - ISO/TR 9839:2023 (Road vehicles, predictive maintenance + ISO 26262‑5)
ISO/TR 9839:2023 is a Technical Report that guides the application of predictive maintenance (PM) to detect and manage degrading faults in safety‑related electrical/electronic (E/E) hardware developed under the ISO 26262 functional safety framework. It surveys state‑of‑the‑art failure mechanisms (with emphasis on semiconductors), defines terminology (e.g., DFDTI, DFRTI, DFHTI, RUL), and outlines how PM techniques can be considered within ISO 26262 safety arguments. Specific technical implementations (e.g., particular ML models or sensor designs) are out of scope.
Key technical topics and requirements
- Definitions and metrics: formal terms for degrading fault, Remaining Useful Life (RUL), Degrading Fault Detection/Reaction/Handling Time Intervals (DFDTI/DFRTI/DFHTI).
- Literature survey: consolidated review of degrading‑fault mechanisms (JEDEC JEP122H and technical publications) and PM methods (PHM, ML, IEEE/IEC references).
- Fault classification & lifecycle: understanding how degrading faults evolve and when they become capable of causing errors or failures.
- Quantification approaches: discussion of Base Failure Rate (BFR) sources - standards, field data, and expert judgment - for estimating degrading fault rates.
- Integration with ISO 26262: approaches to incorporate PM outputs into ISO 26262 safety cases, including evaluation of Diagnostic Coverage (DC) and the impact on Single Point Fault Metric (SPFM) and Latent Fault Metric (LFM).
- Practical considerations: using RUL prediction to schedule replacements, handling random hardware metrics, and treating PM as a dedicated safety measure.
- Informative guidance: Annex A provides an approach to handling degrading faults in the safety lifecycle.
Applications - who should use it
ISO/TR 9839 is directly useful for:
- Functional safety engineers and systems engineers integrating PM into ISO 26262 compliance activities.
- Reliability and prognostics teams implementing Prognostics and Health Management (PHM) and RUL estimation for automotive E/E hardware.
- Semiconductor and hardware designers assessing technology‑specific degrading failure modes.
- OEMs and suppliers of ADAS/ADS, power electronics, and other safety‑critical vehicle systems evaluating diagnostic coverage and maintenance strategies.
- Standards and compliance professionals preparing safety cases that rely on predictive detection and replacement strategies.
Practical value / SEO keywords
This report helps teams link predictive maintenance, remaining useful life (RUL) estimates, and diagnostic coverage to ISO 26262 safety arguments for road vehicles. It is especially relevant where degrading faults (semiconductor wear‑out, EM, TDDB, NBTI, etc.) are significant and PM can reduce risk without prescribing specific PM technologies. Keywords: ISO/TR 9839:2023, predictive maintenance, ISO 26262, degrading faults, E/E hardware, RUL, diagnostic coverage, functional safety.