OTA updates in cars: what they are, how they work – and why they are changing the vehicle trade

An OTA update in a car is quietly but fundamentally changing how vehicles are maintained, valued and traded. Instead of a visit to the workshop, the update runs over the mobile network: software is transferred wirelessly to the vehicle – and it also works in the other direction. Manufacturers can retrieve data directly from the car. For used car dealers and operational users in the vehicle trade, this has concrete consequences, especially when it comes to electric vehicles and battery health. This article explains what an OTA update means technically, which manufacturers use the technology and what new opportunities it opens up for the EV trade.

What is an OTA update in a car?

OTA stands for “over the air” and refers to wireless data transmission between the vehicle and the manufacturer. In concrete terms, an OTA update is transferred to the car via the mobile network or Wi-Fi without the vehicle having to be connected to a diagnostic device or taken to a workshop. What has been familiar from smartphones for years is now also finding its way into passenger cars.

What gets updated is not just simple applications, but also the operating system, control units and safety-relevant software. Depending on the model, a modern car contains several dozen control units – each of which is essentially a small computer. Their software can be specifically updated, corrected or extended via the vehicle’s internet connection.

How does an OTA update work technically?

For an OTA update to work on the car side, three technical requirements must be met: a permanent or on-demand internet connection in the vehicle, a central control unit that distributes the update, and a secure transmission channel from the manufacturer. Most new vehicles today come with a built-in SIM card as standard and communicate via LTE or, increasingly, 5G. During longer stays at home, a Wi-Fi connection can also be used.

The typical process:

1. The manufacturer provides an update on its server.
2. The vehicle checks automatically or on request whether a new package is available.
3. The update is downloaded, verified and installed – usually while the vehicle is parked.
4. After successful installation, the vehicle is notified; in some cases the owner receives a confirmation.

Some updates take place automatically in the background, others have to be actively approved by the driver. Safety-relevant updates are usually installed without active consent, cosmetic or optional functions mostly only after confirmation.

Which manufacturers use OTA updates?

Tesla is considered the pioneer of over-the-air updates in passenger cars – almost all major manufacturers have since followed suit, albeit with different scopes of functions. The following overview shows the status of OTA capability for the brands relevant in the German market:

Manufacturer	OTA functions	Special feature
Tesla	Full scope: operating system, control units, range, assistance systems	Longest experience, own platform architecture
BMW	Remote Software Upgrade for Connected Drive vehicles	Functions can be booked retrospectively
Mercedes-Benz	OTA via the MBUX platform	Focus on infotainment and assistance
Volkswagen Group (VW, Audi, Cupra, Seat, Skoda)	OTA updates for the ID family, Audi Q4 e-tron, Cupra/Seat Born and Tavascan, Skoda Enyaq/Elroq	Expanded since model year 2024
Mazda	Limited OTA functions for connected models	Focus on infotainment
Audi	“Functions on Demand”: LED matrix lights, park assist, navigation	Retrospective activation for a fee

OTA capability depends heavily on the model year and the respective software architecture. Older models with a distributed control unit structure can often only be updated over the air to a limited extent – modern platforms with a central vehicle computer much more comprehensively.

Which data and functions are transferred over the air?

This is where a common misconception lies: An OTA update in a car does not necessarily just mean “software is sent to the car”. OTA describes the wireless connection – and data can flow in both directions via this connection.

Software updates and feature activations

The following is typically transferred from the manufacturer to the vehicle:

• Safety-critical software patches (e.g. for brake control, charging control)
• Improvements to the battery management system in electric cars
• New functions for infotainment, navigation and assistance systems
• Retrospective activation of paid extras (Functions on Demand)
• Corrections that previously would have required a recall to the workshop

In electric vehicles, there is an additional special role: manufacturers use OTA updates to continuously optimise the charging strategy and service life of the battery. The consultancy McKinsey estimates the economic potential of such updates at around 260 euros of additional profit per vehicle, mainly through feature activations.

Data requests from the vehicle to the manufacturer

At least as important – and often underestimated in the vehicle trade – is the opposite direction: vehicles continuously send data to the manufacturers. This includes telemetry data, diagnostic values, charging and driving behaviour and, in electric cars, detailed information on the condition of the high-voltage battery. This data is held by the manufacturer and can be retrieved on request – provided the corresponding interfaces are open.

Until now, this required a vehicle to be connected to a diagnostic device on site. The OTA logic changes this: if data communication between the vehicle and the manufacturer is running anyway, the SoH value of the battery can in principle also be retrieved over the air – by entering the vehicle identification number (VIN), without a plug and without a workshop visit.

OTA and battery data: a new dimension for the EV trade

This is exactly where OTA becomes relevant in practice for used car dealers, fleet managers and rental companies. The battery is the most valuable component of an electric car and largely determines range, residual value and resaleability. The Deutsche Automobil Treuhand (DAT) has now officially included battery health – the State of Health, or SoH for short – in its valuation system for used electric vehicles.

Analyses of large numbers of SoH measurements show that most EV batteries are more robust than often assumed. That is precisely why the individual SoH measurement is so valuable – it distinguishes the well-maintained vehicle from the outlier and makes the difference in the purchase price transparent.

Until now, this required a vehicle to be connected to a diagnostic device on site. The OTA logic changes this: if data communication between the vehicle and the manufacturer is running anyway, the SoH value can in principle also be retrieved over the air – by entering the vehicle identification number (VIN), without a plug and without a workshop visit. autoDATAexperts has implemented exactly this approach with the SoH OverTheAir tool: the VIN is entered, the SoH value comes directly from the manufacturer, and the dealer receives a report with battery health, WLTP range and mileage as a PDF. The tool currently supports selected models from Tesla, BMW, Mazda and the Volkswagen Group (VW, Audi, Cupra, Seat, Skoda). Further manufacturers and models are being added continuously.

Pros and cons of OTA updates in cars for the vehicle trade

From the perspective of a used car dealer or fleet operator, the most important points can be summarised as follows:

Advantages:

• Software stays up to date without a vehicle having to go to the workshop
• Security gaps are closed more quickly
• Functions can be activated retrospectively – this creates added value on resale
• Battery and diagnostic data can be retrieved remotely, which speeds up valuations
• Location and number of vehicles do not matter – even large fleets can be checked efficiently

Challenges:

For everyday B2B business, this means: anyone who understands early on how OTA data flows work can streamline valuation processes, make purchasing decisions more confidently and provide arguments in customer communication that go beyond mileage and year of manufacture.

Security and standards: UN R156 and ISO 21434

As OTA updates have grown in importance, so has the regulatory framework. Two standards are central: UN Regulation R156 obliges manufacturers to operate a certified software update management system so that vehicles can be updated securely throughout their entire service life. ISO 21434 additionally defines the requirements for cybersecurity processes in vehicle manufacturing – from development to operation.

For dealers, this means: updates that are installed over the air on new vehicles today are subject to a documented security standard. Manufacturers must prove that their update infrastructure is protected against manipulation. This strengthens confidence in OTA-based processes – including those that, like SoH data requests, run via the same secure infrastructure.

Conclusion

An OTA update in a car is much more than the digital equivalent of a workshop visit. It is the technical basis for vehicles being permanently connected to their manufacturers – in both directions. This opens up a new field for the vehicle trade: data that used to be available only via a connected diagnostic device can now be retrieved remotely. In electric vehicles, battery health is the most prominent example. Tools such as SoH OverTheAir from autoDATAexperts show how this data flow can be used in practice for purchasing, fleet valuation or lease returns – without hardware, without a workshop, simply via a VIN query.

Would you like to better assess how battery data can be integrated into your purchasing or valuation process? autoDATAexperts supports dealers, fleets and rental companies in making efficient use of the SoH value via VIN query – a no-obligation introductory call will clarify within a few minutes whether this fits your use case.

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