The independent claim is where the value lives, and this application has three of them doing identical work. US20260208784A1, published 23 July 2026, assigned to GM Global Technology Operations LLC and naming Mahdokht Ezati, Seyedeh Asal Nahidi and Amin Habibnejad Korayem, is classified under CPC B62D 5/006, B62D 5/0409 and B62D 5/046. Claim 1 is a steer-by-wire system, claim 13 a vehicle having one, claim 19 a method of operating one.

The operative core is word-for-word consistent across all three: determine an actual value of the C-factor; determine a C-factor difference against the nominal value when the actual is less than the nominal; determine a degradation status from that difference; and provide a response based on the degradation status. The nominal value is defined the same way in each — a ratio of travel of the steering rack per revolution of the pinion gear.

The limitation that decides infringement

Two limitations carry the scope. The first is the conditional. Every independent claim triggers only when the actual value is less than the nominal value. A system that computed the difference unconditionally, or that flagged degradation on a ratio exceeding nominal, would not practise these claims as written. That is a real and deliberate narrowing, and it is present in all three independents, so there is no broader independent claim to fall back on.

The second is the definition itself. The nominal value is tied to rack travel per pinion revolution. That anchors the claims to rack-and-pinion geometry specifically. A steer-by-wire architecture using a different road-wheel actuation arrangement — no rack, no pinion — would fall outside the claim language regardless of whether it performed the same diagnostic comparison. Scope here is bounded by mechanism, not just by method.

The system of claim 1, wherein the controller is configured to determine the degradation status by comparing an absolute value of the C-factor difference to a predetermined range of values.— System and Method for Identifying Degradation in a Steer-by-Wire System, US20260208784A1

Where the fallbacks actually sit

The dependent claims are distributed very unevenly, and that matters for what survives if claim 1 narrows. The system chain carries eleven dependents, claims 2 through 12, and they hold everything technically substantive: the absolute-value comparison against a predetermined range (claim 2), the tiered responses (claims 3 through 7), and the estimation machinery. Claim 8 derives the actual value from an estimated steering rack displacement and a pinion angle displacement. Claim 9 sources that estimate from road wheel actuator parameters. Claim 10 enumerates them — a motor current, a motor voltage, a motor inductance, a motor resistance and a back electromotive force, plus a mass, a stiffness, a damping and a steering arm length. Claim 11 recites an observer using estimated rack force and motor voltage as control inputs with motor torque as the measurable control output.

The vehicle chain gets five dependents (claims 14 through 18) which mirror the response tiers but never reach the estimation machinery. The method chain gets exactly one, claim 20, combining two response tiers. So if the independent claims narrow during prosecution, the system claim has a deep ladder of positions to retreat down, the vehicle claim a shallow one, and the method claim almost none. For a diagnostic that would most naturally be asserted as a method performed by a controller, that distribution is worth noting. It is the apparatus, not the process, that has been armoured.

The three independents introduce the nominal value in three different ways, and comparing them is instructive. Claim 19, the method claim, does it correctly: it recites "a nominal Cfactor" on first use, then refers back to "the nominal Cfactor", then defines it. Claim 13 pre-empts the problem in its preamble by reciting a controller "configured to apply a nominal Cfactor" before the limitation that uses it.

Claim 1 does neither. It refers to "the nominal Cfactor" with a definite article, and only afterwards, in a trailing wherein clause, states that the system "includes a nominal Cfactor defining a ratio of travel of the steering rack per revolution of the pinion gear". The element is used before it is introduced — an antecedent-basis irregularity of exactly the kind that draws a rejection and gets fixed by amendment. It does not obscure what is meant, and claims 13 and 19 show the drafter knew the cleaner forms. It is simply the broadest claim carrying the sloppiest recitation, and the one an examiner will reach for first.

Three further published-text defects are reproduced rather than repaired. The record spells the term four ways — the estimated value as Ĉfactor with a circumflex and no separator, the designed value as Cfactor, and the comparison as C-factor difference with a hyphen, alongside compensation C-factor. Claim 10 reads "include, a mass" with a stray comma and introduces "an electrical motor" as a new element where claim 9 refers only to road wheel actuator parameters. And claim 18 reads "the alert include at least one of", missing the verb agreement its counterpart claim 7 gets right.

None of these changes scope. All are the kind of thing corrected between publication and grant, which is the standing point: this is a published application, it is unenforceable in this form, and the claim set described here is the one as filed rather than the one that will issue. For the adjacent position, GM published a second steer-by-wire application in the same drop directed at manipulating a baseline steering ratio, alongside filings on safety-integrity monitoring, lidar-obstruction validation and environment-complexity scoring.