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Reading OEM ADAS procedures accurately is a skill, and like most skills, it takes deliberate practice to develop.
These documents are written by engineers, updated frequently, and use language that carries specific technical meaning that isn't always obvious on first read even though the stakes are high. If you misinterpret a requirement as optional, you could be looking at safety and liability exposure. And if you misread optional guidance as mandatory, you could end up with customer friction over what they perceive to be upcharge services.
This post covers how to read OEM procedures accurately, including how to understand document structure, interpret technical language, and know when a single document isn't the whole picture.
Understanding the document hierarchy
OEM documentation for ADAS isn't a single source. It’s actually a layered system, and knowing where each document sits in that hierarchy matters.
Service manual procedures are the foundation. They provide step-by-step calibration instructions, required equipment, environmental conditions, and measurement specifications for each vehicle configuration. But they're often written broadly to cover a range of scenarios, which is where ambiguous language like “may” can appear.
Position statements sit above service manual procedures and frequently supersede them. When a manufacturer issues a position statement clarifying that a specific repair always requires calibration, that statement overrides the more cautious language in the service manual. Shops can easily miss calibrations, or argue incorrectly with insurers, simply because they're working from the service manual alone without checking for applicable position statements.
Technical service bulletins (TSBs) update both. A TSB can change "may require" to "must require," introduce additional steps, or clarify which conditions trigger a requirement. They're issued in response to real-world field data, which means a procedure that used permissive language at launch may have been tightened by a TSB issued months later.
Reading any single document in isolation, without checking whether it's been updated or overridden, is one of the most common ways shops misinterpret OEM requirements.
Decoding the language
Once you understand the document hierarchy, the specific language used becomes much easier to interpret. This is true even in “grey areas” where the language seems confusing.
"Must" or "is required" appears when safety systems will definitely malfunction without calibration, when the repair directly affects sensor mounting points or positioning, or when regulatory requirements mandate specific procedures. These are non-negotiable, and insurers treat them accordingly.
"May" usually signals that calibration requirements depend on specific circumstances. A single procedure often covers multiple repair scenarios, and not every scenario triggers the same requirements. The procedure is providing guidance, but the determination of whether it applies falls to the technician's professional judgment based on the actual repair performed.
"Should" or "recommend" indicates best practices that provide an additional safety margin. These aren't always mandatory, but they carry weight. If a vehicle is later involved in an incident and documentation shows a recommended calibration was skipped, that decision will be scrutinized.
Manufacturers tend to use cautious "may" phrasing when real-world conditions vary too much for a blanket requirement, or when they're covering multiple scenarios in a single procedure. Over time, as field data accumulates, that language often shifts toward "must." Checking for TSBs and position statements is how you find out whether that shift has already happened for the procedure you're looking at.
Why VIN-specific context matters
It’s essential to remember that a 2024 Subaru Forester has completely different ADAS calibration requirements compared to a 2025 Forester, even if they look nearly identical.
Two vehicles that look identical can have entirely different ADAS configurations. Same model, same year, different trim levels or option packages can mean different camera mounting angles, different radar sensor specifications, or different software versions requiring different calibration procedures. A procedure that's accurate for one VIN may be wrong for another.
Pulling a general procedure for a make and model isn't sufficient. You need to look at up-to-date VIN-specific calibration procedures for each vehicle.
The practical default
What happens when genuine uncertainty remains after checking the service manual, applicable position statements, and relevant TSBs for a specific VIN? We almost always recommend playing it safe.
Talk to the customer, let them know that you recommend calibration based on manufacturer guidelines, and calibrate.
The cost of calibration is minimal compared to the consequences of a safety system that doesn't function when a customer needs it. Professional judgment should default toward caution when the documentation doesn't resolve the question clearly.
When a procedure uses ambiguous language and you determine calibration is required, your documentation needs to do more work than it would for a clear "must" scenario.
Insurers approve clear requirements straightforwardly, but those gray areas require explanation unless you want to end up with denied or delayed decisions. Photos of damage, diagnostic scan results, and a written rationale for why calibration was deemed necessary based on the specific repair performed will support claims and protect the shop if questions arise later.
The same logic applies when you determine calibration isn't required. If a procedure says "may be required" and your assessment is that it wasn't needed in this case, that determination should be documented with the same specificity. Undocumented decisions in either direction create exposure.
The role of technician training
Reading OEM procedures accurately requires ongoing training investment, and the data shows most shops are struggling to keep pace. This is important to highlight, because people are a critical part of whether or not your shop can increase revenue. Despite this, there’s a clear training gap that many shops are struggling with.
According to Revv's 2025 ADAS Calibration Benchmark Report, 59% of shops identified better technician training as the key factor that would make them more likely to bring additional calibrations in-house. At the same time, 47% cite keeping up with changing OEM procedures as one of their biggest training challenges, and 27% of ADAS jobs involve procedures that have changed since the last similar repair was performed.
Technicians may be reading a procedure they've seen before and applying what they learned in a training session months ago, without realizing the requirements have since been updated. Most classroom or video-based training captures a moment in time, while OEM procedures continue to evolve.
As a result, training needs to account for the frequently changing nature of OEM requirements. Teach technicians how to read reports, how to make decisions, and how to access the information they need if they run into something new.
Reading procedures accurately, at scale
The challenge for busy shops isn't understanding these interpretation principles in theory. It's applying them consistently across dozens of vehicles and repairs while tracking which procedures have been updated by position statements or TSBs.
Revv addresses this by providing VIN-specific OEM procedures and position statements in one place, so technicians don’t need to cross-reference multiple manufacturer sources or work from outdated documents.
Book a demo to see how Revv helps shops read OEM procedures accurately and document their decisions consistently.
