Title: The Forgotten Half of ISO 26262: Production and Service | ISO 26262 Academy URL: https://iso26262.academy/blog/forgotten-half-of-iso-26262-production-and-service Description: ISO 26262 Part 7 explained: how safety-related special characteristics carry design intent through production and service, shown on a steering angle sensor. --- [Technical](https://iso26262.academy/blog/category/technical) # The Forgotten Half of ISO 26262: Production and Service ![A car raised on a red axle stand in a workshop, its front suspension strut removed and lying on the floor, with the steering tie rod ends hanging free while a mechanic works underneath.](https://iso26262.academy/edge-media/p/blog/images/2026/10/239fc556-b082-48e9-8504-ed87cd74093e-1920.webp) A wheel alignment that touches no sensor and still leaves the stability control with the wrong idea of straight ahead. ISO 26262 Part 7 is where design intent survives the factory floor and the workshop, or gets lost there. The carrier is the safety-related special characteristic, and the service instruction decides whether a garage restores it or quietly undoes it. New article, with a steering angle sensor zero point as the worked example. ![ISO 26262 Academy](https://iso26262.academy/logo.png) ISO 26262 Academy 29 October 2026 7 min read Share Text size The effort in an ISO 26262 project is front-loaded. The hazard analysis, the safety concepts, the hardware metrics and the software verification are done before series production starts. After that, the design has to survive a production line building it hundreds of thousands of times, and then a decade or more of tyre fitters, alignment benches and independent garages. ISO 26262-7:2018 covers that period: production, operation, service and decommissioning. It is a short part, and in many safety plans it gets a single line. It deserves more, because this is where design intent either reaches the vehicle on the road or quietly stops doing so. ## What carries the design into the plant and the workshop The carrier is a safety-related special characteristic. ISO 26262-1:2018, Clause 3 describes it as a property of the product, or of the way it is made, where a plausible deviation can erode functional safety: a torque, a tolerance, a calibration, a configuration. Development identifies these. ISO 26262-4:2018, Clause 6 has the technical safety concept specify them, together with service requirements and diagnostics that can show a repair actually worked. Part 7 then hands the same characteristic to two very different audiences. Clause 5 puts it into the production plan and the production control plan with a pass criterion, and into the instructions for service as a control step with criteria that verify it after the work. Clause 6 runs the line and records each control result against the vehicle. Clause 7 has service carried out and documented to those instructions. So the plant and the workshop are asked the same question about the same number, years apart, by people with different tools and none of the development context. Whether the answer stays right depends mostly on how the service instruction is written. ## A worked example: the steering angle zero point In this fictional design, a stability control function estimates the yaw rate the driver is asking for from the steering wheel angle and the vehicle speed, and compares it with the yaw rate the car actually has. The angle comes from a sensor on the steering column. For the comparison to mean anything, the sensor's zero has to coincide with the road wheels pointing straight ahead. The safety analysis showed that the intervention thresholds stay valid while that zero is within ±1.5° of steering wheel angle. That window is the special characteristic, and it is not a property of the sensor. It is a relation between three parts: the sensor on the column, the rack, and the track rods whose length decides where the wheels point. ![Schematic of a steering system. A steering wheel sits on a column carrying the steering angle sensor, which feeds the stability control unit. The column drives a rack and pinion, and two track rods with adjuster sleeves connect the rack to the road wheels, which point straight ahead. Three numbered cards explain the parts: the sensor reports the column angle against the zero it learned, the rack turns column angle into rack travel, and the track rod length decides where the wheels point for a given rack position. A green card states the characteristic: the sensor zero within plus or minus 1.5 degrees of the column angle at which the wheels point straight, set at end of line after alignment. A strip of workshop jobs below marks wheel alignment, track rod or rack replacement and sensor replacement in red as jobs that move the relation, and tyres or brake pads in grey as jobs that do not.](https://iso26262.academy/edge-media/p/blog/diagrams/2026/10/58302c0a-5708-428d-afb3-30ab0bc7eecc.svg) Figure 1. The steering angle zero is a relation between three parts, and most of the workshop jobs that move it never touch the sensor. On the line, the control plan places the calibration at end of line, after the alignment station, with the wheels set straight on a level rig. The tester writes the zero into the controller, reads it back, checks it against ±1.5° and stores the result with the vehicle identification number. The order matters: a zero taken before alignment is taken against the wrong straight ahead. The station does this on every vehicle with the same equipment, and its capability is kept under control. Keep learning [Free course preview Production, Operation, Service & Decommissioning](https://iso26262.academy/features/concepts/production-operation-service) [Or test yourself with the 7-question demo exam](https://iso26262.academy/demo-exam) ## Where the intent gets lost Four years later the car hits a kerb and goes to a garage for an alignment. The technician sets toe, then centres the steering wheel by lengthening one track rod and shortening the other. Nothing electronic is touched and the tester shows no fault code. Yet the column now sits about 5° away from where it was when the wheels point straight, and the sensor still reports the zero it learned in the plant. The stability control now believes the driver is asking for a gentle turn on every straight road. Its plausibility monitor only flags offsets above 10°, because it has to tolerate crosswind, camber and sensor noise. So 5° sits in a silent band: outside the window the thresholds were tuned for, inside what the diagnostics can see. Nothing tells the driver or the workshop. The service instruction decides what happens next. If it is tied to the part, as in "after replacing the steering angle sensor, calibrate it", the alignment never triggers it, and the car runs with 5° until the sensor itself is replaced years later. If it is tied to the characteristic, with alignment and track rod or rack work as triggers and the same ±1.5° criterion and read-back as the line, the workshop restores what the plant built. ![A chart of steering angle offset in degrees over twelve years of one vehicle's life. A green band up to 1.5 degrees is the acceptance window, an amber band from 1.5 to 10 degrees is a silent band with no lamp and no fault code, and above 10 degrees the monitor flags the offset. A solid red line starts at 0.4 degrees at end of line, jumps to 5 degrees at year 4 after a kerb strike and alignment, and stays there for five years until the sensor is replaced at year 9. A dashed green line shows the same vehicle when the alignment triggers a calibration with the same check: it drops back to 0.6 degrees at year 4 and stays inside the window.](https://iso26262.academy/edge-media/p/blog/diagrams/2026/10/e1245550-c9a1-48bd-89a0-4c92f20e0496.svg) Figure 2. The same vehicle under two service instructions. Tied to the part, the offset sits in the silent band for five years. ## A handover across decades Development knows why the window is ±1.5°. The plant knows how to hit it once per vehicle. The workshop meets it years later without either piece of knowledge. Part 7 exists to carry that knowledge across: the characteristic and its criterion arrive from development as inputs to planning, production controls and records them, and service verifies them after every job that can disturb them. When planning shows that a repair cannot be verified with the diagnostics on board, Part 7 sends that back to development as a new requirement, for example a calibration status the workshop tester can read. The useful question for each safety-related special characteristic is which workshop jobs can move it, not which part carries it. In this example the honest answer included a job that never touches a sensor. The [Production, Operation, Service and Decommissioning](https://iso26262.academy/features/concepts/production-operation-service) concept page goes through all of Part 7: its structure and work products, the release for production, special characteristics and process failure analysis, the production control plan and process capability, user and rescue information, service, field monitoring and change, end of life for traction batteries and airbags, confirmation measures, and the recurring pitfalls, with worked examples from the plant to the dismantler. ## Abbreviations & Key Definitions - **Safety-related special characteristic** - A product or process property, identified in development, whose deviation in production or service can reduce functional safety. - **Production control plan** - The plan naming the production step, method, test equipment and pass criterion for each check of a characteristic. - **Toe** - The angle of the road wheels relative to the vehicle centreline, set by the track rod length. Related on the Platform [Production, Operation, Service and Decommissioning Concept](https://iso26262.academy/features/concepts/production-operation-service) Last updated: 29 October 2026 Tags [safety-engineering](https://iso26262.academy/blog/tag/safety-engineering) [calibration](https://iso26262.academy/blog/tag/calibration) [functional-safety](https://iso26262.academy/blog/tag/functional-safety) [systematic-faults](https://iso26262.academy/blog/tag/systematic-faults) [iso-26262](https://iso26262.academy/blog/tag/iso-26262) Share this article ## Read the full Production, Operation, Service and Decommissioning concept From HARA to Safety Mechanisms - master every concept with clear, practical explanations and real-world examples. [Browse Concepts](https://iso26262.academy/features/concepts/production-operation-service) Keep learning ## Guides on this topic. The guide this article draws on, and where the topic leads next. [Browse all guides](https://iso26262.academy/features/concepts#library) - Verification and assessment [Production, Operation, Service & Decommissioning](https://iso26262.academy/features/concepts/production-operation-service) ISO 26262-7 governs the safety lifecycle after design release: production controls, operation and service instructions, field monitoring, repair and diagnostics, and safe end-of-life decommissioning of high-voltage and pyrotechnic systems. [Expert](https://iso26262.academy/pricing#plan-advanced) 10 chapters - Vehicle domains [Actuator Safety](https://iso26262.academy/features/concepts/actuator-safety) Motors, valves and relays are where safety goals become physical - learn how actuation channels fail stuck or runaway, how feedback and diagnostics catch it, and how safe states from de-energize to active hold are engineered and quantified. [Expert](https://iso26262.academy/pricing#plan-advanced) 14 chapters - Verification and assessment [Verification & Validation](https://iso26262.academy/features/concepts/verification-validation) Learn multi-level verification from unit testing through system and vehicle validation with ASIL-dependent coverage criteria. Covers reviews, HIL/SIL testing, fault injection, MC/DC coverage, and evidence management. [Expert](https://iso26262.academy/pricing#plan-advanced) 14 chapters ## Comments ## Related Articles [![A calibration engineer sits in the open driver door of a silver hatchback parked on a proving-ground slope, tuning values on a laptop that shows a calibration map, cabled to an interface box on the door sill.](https://iso26262.academy/edge-media/p/blog/images/2026/10/0d6be7e0-d513-434e-af22-219774d777b2-1200.webp) Technical ### Calibration and Configuration Data in ISO 26262 7 min Oct 12](https://iso26262.academy/blog/understanding-calibration-and-parameter-safety-in-iso-26262) [![Three engineers at a lab workbench: one points at a measurement plot on a laptop, a senior colleague listens and another takes notes, with a prototype car on a lift and test equipment behind them.](https://iso26262.academy/edge-media/p/blog/images/2026/10/5ab3c51b-1a48-413c-8990-7713591278c7-1200.webp) Technical ### Evaluating ISO 26262 Safety Culture: Evidence Over Slogans 7 min Oct 8](https://iso26262.academy/blog/evaluating-iso-26262-safety-culture-evidence-over-slogans) [![Three engineers look at a laptop together beside a vehicle test rig with a steering wheel and wiring in a development workshop.](https://iso26262.academy/edge-media/p/blog/images/2026/10/a0c43182-ee0f-4941-a4a5-d3e18644e82a-1200.webp) Technical ### ISO 26262 Safety Culture: Competence and Accountability 7 min Oct 6](https://iso26262.academy/blog/iso-26262-safety-culture-competence-and-accountability)