Toyota urges Japanese carmakers to standardise more components

Cooperation would begin with parts customers never see

According to Automotive News, Sato wants closer cooperation between Toyota, Honda, Nissan, Mazda, Subaru, Mitsubishi and Suzuki. Nissan chief Ivan Espinosa has publicly backed the idea, although the manufacturers have yet to agree a common roadmap.

Sato’s proposal focuses mainly on components that do not define a car’s design or driving characteristics. These could include wiring harnesses, hoses, couplings, fasteners and electrical connectors.

The manufacturers would not necessarily have to use exactly the same part. Instead, they could agree common dimensions, interfaces, material requirements and test procedures. A supplier could then develop one core solution for several carmakers, adapting only its packaging, load tolerance and operating conditions.

No customer chooses a car because of its connector housing or hose coupling. Carmakers still spend time and money designing, testing and putting those parts into production.

Shared components need not dilute brand identity

The car industry already shares components extensively, but usually within a single group or manufacturing alliance. Sato’s proposal would extend that cooperation to direct competitors and could cover a large part of Japan’s automotive sector.

Using the same connector or fastener would not make a Toyota steer like a Nissan. It would, however, reduce the number of part variants, lower inventory requirements and cut spending on production jigs and tooling.

Higher production volumes would also reduce unit costs. Rather than producing several nearly identical parts in smaller batches, a supplier could manufacture a standard component at scale for multiple carmakers.

The greater benefit may come during development. Engineers would no longer need to create a new connection or interface for every model, suppliers would not have to manage dozens of similar variants, and factories could share more tooling and assembly processes.

That would allow carmakers to direct money and engineering effort towards areas where customers genuinely notice the difference: faster charging, lower energy consumption, better driver-assistance systems and more polished driving dynamics.

Software-defined vehicles need common interfaces

Standardisation becomes particularly important for software-defined vehicles, or SDVs. Software controls an increasing share of their functions, while over-the-air updates allow manufacturers to alter a car’s features after it has left the factory.

If every manufacturer uses different control units, data structures and programming interfaces, developers must re-engineer the same function several times. Common APIs, software layers and hardware abstraction layers would allow the same core function to operate across different electronic architectures.

Each manufacturer could still determine how the feature behaves, how the interface looks and how the car feels to use. A shared foundation would simply reduce the need to develop the same basic software repeatedly.

Japan’s Ministry of Economy, Trade and Industry identifies nationwide API standardisation in its Mobility DX programme as one way to accelerate SDV development. In the longer term, Japan also wants suitable domestic solutions to become international standards.

Honda and Nissan began joint research into core SDV technologies in 2024. Their current cooperation plan also covers a central computing unit that the two companies could use in models launched during the next decade.

That project is narrower than Sato’s industry-wide proposal, but follows the same principle: manufacturers share the technical foundations customers do not see, then compete on the qualities of the cars built around them.

Competition from China is forcing the pace

Japanese carmakers built their strength on close supplier relationships, rigorous quality control and long development cycles. That model produces dependable cars, but risks becoming too slow in the era of software and electric powertrains.

Chinese manufacturers can draw on a vast home market, short development cycles and a broad supplier base. They develop battery systems, electronics, software and manufacturing processes in parallel, bringing new models to market faster than many Japanese rivals.

Component standardisation will not solve the challenges of developing EVs or software. It could, however, reduce duplicated engineering work and free resources for the areas in which Japanese manufacturers must keep pace with Chinese and US companies.

A shared wiring harness will not turn a mediocre EV into a good one. It may, however, leave more money for a better battery, more efficient thermal management or faster software development.

European manufacturers already share platforms and software

European carmakers are already familiar with the benefits of shared components. Volkswagen’s MQB modular platform allows models of different sizes to use similar floor structures, powertrain layouts and manufacturing solutions.

MQB remains a Volkswagen Group system, however. The Japanese proposal would go further: Toyota, Honda, Nissan and the other manufacturers would remain separate companies while using common interfaces and component standards in selected areas.

In software development, European cooperation already extends beyond group boundaries. Carmakers, suppliers and technology companies are developing shared open-source software components to avoid recreating the same basic code.

Greater cooperation between Japanese manufacturers could also benefit cars sold in Europe. Fewer component variants could reduce costs, speed up the adoption of new electronic architectures and simplify parts sourcing.

The effects would not reach production cars until future model generations. Manufacturers would first have to agree the standards, select suppliers, validate the components and integrate them into new vehicle programmes.

Standardisation can magnify the impact of a single fault

Shared components deliver major economies of scale, but they also introduce new risks. If several manufacturers use the same defective connector, control unit or software layer, a recall could affect multiple brands and millions of vehicles at once.

An overly narrow supplier base would also increase supply-chain risk. A factory shutdown, natural disaster or quality problem at a single supplier could disrupt several manufacturers simultaneously.

Too much standardisation could also slow innovation if carmakers commit too early to a single technical architecture. They must therefore draw a clear line between the areas in which they cooperate and those in which they compete.

Common standards make sense for components that customers neither see nor feel. Manufacturers must retain the freedom to develop their own body structures, chassis, powertrains, software and user experience.

The logic behind Koji Sato’s proposal is simple: a carmaker does not need to design every bracket, connector and hose from scratch merely to distinguish itself from a rival. The winners may be the companies that know exactly which components are worth sharing — and which must remain a source of competitive advantage.