Honda Recalls 635,808 Vehicles Because Software Can Disable Steering Assist

A calculation intended to compensate for road conditions can instead make certain Honda and Acura vehicles substantially harder to steer. Under specific operating conditions, the software may attempt to divide a value by zero, register an internal error and place the electric power steering system into a failsafe mode that shuts off steering assistance.

Honda is recalling 635,808 vehicles in the United States because of that configuration. The campaign covers certain 2021-2025 Acura TLX sedans, 2022-2024 Acura MDX SUVs and 2023-2025 Honda Pilot SUVs. Honda reported the defect to the National Highway Traffic Safety Administration on October 29, 2026, under recall number 26V721000.

The steering wheel remains mechanically connected to the road wheels when the fault occurs, so drivers do not lose the ability to steer. They may, however, need to apply considerably more force than expected. The change can be especially pronounced during parking and other low-speed maneuvers, where power assistance normally does much of the work. NHTSA warns that the resulting loss of assistance could reduce controllability and increase the risk of a crash or injury.

Why a calculation error can remove steering assistance

The fault is within supplier-developed electric power steering software and involves the Driver Attention Monitor’s road-condition compensation calculation. A floating-point division-by-zero operation does not produce a usable result for the control software. That internal error then invokes the system’s configured response.

The safety problem is not only the invalid calculation, but what the software has been told to do after detecting it. Honda determined that the response was incorrectly configured to enter failsafe mode and disable electric steering assistance. Warning indicators illuminate in the instrument cluster when that mode activates, but the driver may already be confronting an abrupt increase in steering effort.

This illustrates the systems-level role of a failsafe. A controller needs a defined response when incoming data or an internal computation falls outside its expected range. That response must place the vehicle in a condition that remains manageable for the driver. Here, the mechanical steering path remains available, but removing assistance transfers a much larger physical workload to the person behind the wheel.

That workload is sensitive to operating conditions. At higher road speeds, a vehicle generally requires less steering assistance. At parking speeds, tire forces make the wheel harder to turn, so an unexpected loss of assistance is more noticeable. The same fault can therefore produce very different human-factors consequences depending on when it occurs.

Functional-safety engineering treats this interaction among electronics, mechanical fallback and driver response as one system. A U.S. Department of Transportation-supported assessment of generic electric power steering applied ISO 26262 methods and identified vehicle-level safety goals, system requirements and potential diagnostic-coverage needs. Honda’s recall provides a concrete example of why both fault detection and the programmed reaction to a detected fault require validation.

A software repair across three vehicle lines

The 2025 Honda Pilot represents the largest stated portion of the campaign, with 240,830 potentially affected vehicles almost 38% of the total recall population. The broader campaign spans three model lines and two brands because the affected control software is shared across multiple applications.

Authorized dealers will reprogram the electric power steering control unit with corrected software rather than replace major steering hardware. The repair will be performed free of charge regardless of whether the vehicle remains under its original warranty. Dealer notifications were scheduled to begin around October 30, while owner notification letters are expected to start December 14.

Honda has not issued a Do Not Drive warning. Until the corrected software is installed, affected vehicles remain mechanically steerable, but drivers could encounter a sudden and substantial increase in effort if the system enters failsafe mode. The remedy addresses the control logic directly: correcting both the calculation behavior and the response that turned an internal software error into the loss of an assistance function drivers routinely depend on.

By Thomas Caldwell — AMI’s senior editor for mechanical and mobility engineering, covering vehicle electronics, systems integration, electrification, chassis systems, propulsion, and safety policy.