Volkswagen Dieselgate — How Clean Diesel Became the Defining Marketing Fraud of the Decade

Situation

On 18 September 2015, the US Environmental Protection Agency issued a Notice of Violation to Volkswagen AG. The document, signed by EPA Enforcement Director Phillip Brooks, alleged that Volkswagen had installed "defeat device" software in approximately 482,000 diesel vehicles sold in the United States between model years 2009 and 2015. The software was designed to recognise when a vehicle was undergoing a regulatory emissions test — by monitoring steering wheel angle, vehicle speed patterns, barometric pressure, and duration of engine operation — and switch to a compliant emissions-control mode for the duration of the test. During normal driving, the vehicles emitted nitrogen oxides at up to 40 times the US legal limit.

The cars in question were not marginal products in Volkswagen''s portfolio. They were the centrepiece of the most ambitious marketing campaign the company had run in North America since the Beetle relaunch. Under the "Clean Diesel" banner, Volkswagen, Audi, and Porsche had positioned TDI (Turbocharged Direct Injection) engines as the sustainable premium choice for environmentally conscious consumers who also wanted performance. The marketing narrative ran from 2008 to 2015, supported by an estimated $100m+ of annual US media spend, an Academy Award-nominated Super Bowl ad featuring Darth Vader (2011), and a repeated claim — litigated explicitly in the DoJ''s 2016 civil complaint — that VW TDI engines were "90% cleaner" than predecessor models while still delivering the torque and fuel economy consumers expected.

The strategic context is essential. Between 2007 and 2015, Volkswagen had been pursuing an explicit goal set by then-CEO Martin Winterkorn: to become the world''s largest automaker by 2018, overtaking Toyota and General Motors. The US market, in which VW''s share had historically been weak, was the critical battleground. American consumers had largely rejected diesel after the GM / Oldsmobile diesel failures of the 1980s, and Japanese hybrids — the Toyota Prius in particular — had captured the environmentally conscious buyer segment. Volkswagen''s answer was to reposition diesel as the "European solution" to sustainability: higher torque, better highway mileage, lower CO2 per mile than petrol equivalents, and "90% cleaner" NOx emissions than earlier generations. This was the story Audi''s "Truth in Engineering" tagline was built to underwrite.

The problem was that the engineering did not match the marketing. The EA 189 diesel engine, the workhorse of the Clean Diesel programme, had been designed to meet European emissions standards that were substantially less strict on NOx than the US Tier 2 Bin 5 standard it needed to satisfy to be sold in the North American market. Engineers at Volkswagen AG and its Audi subsidiary knew, as early as 2006, that meeting the US standard in real-world driving while preserving the fuel economy and performance the marketing campaign promised would require either a substantially more expensive urea-based selective catalytic reduction (SCR) system, a less aggressive engine calibration that would damage the vehicle''s advertised performance, or a willingness to accept that the cars could not legally be sold in the US. Instead, a software team led by engine-management engineers chose a fourth option: write code that made the cars behave differently when they were being tested.

In 2014, a research team at West Virginia University''s Center for Alternative Fuels, Engines and Emissions, funded by the International Council on Clean Transportation, ran independent on-road emissions tests on a VW Jetta, a VW Passat, and a BMW X5. The BMW was compliant. The Volkswagens emitted 5 to 35 times the legal NOx limit under real-world conditions. The ICCT researchers — Arvind Thiruvengadam, Marc Besch, and Daniel Carder — had not been looking for a defeat device. Their original research question was simply whether US diesel emissions regulations could be met in the real world, a question their European funders wanted answered in the hope that it would support the case for tighter European enforcement. They found the opposite of what they expected. Their Volkswagen test vehicles emitted so much more NOx on the road than in the lab that they initially suspected an equipment malfunction. When they rechecked their instruments and repeated the tests, the numbers stayed the same. The ICCT published the finding in May 2014. For 16 months, the California Air Resources Board and the EPA pressed VW for an explanation. The company offered a sequence of technical justifications, promised a voluntary recall, and — according to the EPA''s subsequent Notice of Violation — only admitted the existence of the defeat device in September 2015 when the EPA threatened to withhold certification for the 2016 model year.

The public positioning of Clean Diesel during this entire period is worth attending to. Volkswagen of America ran television advertising — including one notable 2010 spot in which three elderly women debate whether a modern diesel engine could really be clean, and a younger driver proves it by holding a white handkerchief to the exhaust pipe — that asserted the new TDI engines were cleaner than consumers assumed. Audi''s campaigns emphasised engineering rigour and independent verification. The "Truth in Engineering" tagline, registered as an Audi trademark in 2007, was displayed across print, television, and digital advertising in the US, Canada, and the UK. At no point during the 2014-2015 period, when the ICCT findings were already in public circulation, did Volkswagen''s marketing communications acknowledge the discrepancy. The message to consumers remained unchanged: Clean Diesel was cleaner. The engineering story Audi was telling was still true. Whatever was happening in the regulatory correspondence between CARB, EPA, and Wolfsburg was happening in a register the marketing function did not treat as its concern.

Decision

Dieselgate was not a single decision. It was a cascade of decisions across engineering, marketing, and executive governance, over nearly a decade, made by people who individually could have stopped it and collectively did not.

The engineering decision came first. In the early 2000s, the diesel engineering team at VW''s Wolfsburg headquarters, under powertrain chief Rudolf Krebs and the US product team led at various points by James Liang and Oliver Schmidt, faced an irreconcilable trade-off. The EA 189 engine, as specified, could not simultaneously meet US NOx limits, deliver advertised performance, and preserve the cost structure required by Winterkorn''s US market-share targets. A decision was made — first in Wolfsburg and later in the United States — to deploy software that would detect test conditions and produce compliant results. The software was adapted from a Bosch engine-management module; Bosch had reportedly written to VW warning that use of the "acoustic mode" code for defeat purposes would constitute a legal violation. The warning was ignored. James Liang later pleaded guilty to conspiracy charges in the US District Court for the Eastern District of Michigan in September 2016. Oliver Schmidt, VW''s head of environmental regulatory compliance in the US, was arrested in Miami in January 2017 and pleaded guilty in August of that year.

The marketing decision was parallel and independent. VW''s US marketing team, working with agency of record Deutsch LA, developed the Clean Diesel campaign on the basis of engineering claims provided by the Wolfsburg product team. There is no evidence that the agency knew the claims were fraudulent. There is, however, substantial evidence — gathered by the DoJ''s investigation and reported by Jack Ewing in his 2017 book Faster, Higher, Farther — that VW''s US marketing executives continued to amplify the "90% cleaner" claim after internal engineering reviews in 2011-2013 had raised questions about real-world NOx performance. The marketing decision, in other words, was not a fraud decision. It was a decision to accept the engineering team''s assurances without the kind of independent verification that the autonomy test would have demanded. Marketers sold what engineers told them was true, without asking the question the regulators would eventually ask.

The governance decision was the most consequential. Martin Winterkorn, who had become CEO in January 2007, ran Volkswagen with a famously confrontational management culture that Jack Ewing, Bethany McLean, and others have described as intolerant of dissent. Internal memos made public during the DoJ''s investigation showed that Winterkorn was briefed on the emissions discrepancy issue as early as May 2014, when a memo from VW''s Product Safety Committee detailed the ICCT findings and flagged a "problem" with US diesel compliance. Winterkorn has disputed the extent of his awareness, and no German criminal court has convicted him as of 2025. But the governance failure is not a criminal question. It is the question of what a chief executive knew, when, and what they asked the organisation to do about it. On 23 September 2015, five days after the EPA''s Notice of Violation, Winterkorn resigned. His resignation statement read: "I accept responsibility for the irregularities that have been found in diesel engines and have therefore requested the Supervisory Board to agree on terminating my function as CEO of the Volkswagen Group. I am doing this in the interests of the company even though I am not aware of any wrongdoing on my part."

The decision that was never made — and this is what the F11 framework asks marketers to notice — was the decision to run the autonomy test on the Clean Diesel campaign. Nobody inside VW, Audi, or Deutsch LA appears to have asked the basic question: if consumers understood what this engine actually emits on the road, would they still choose it over a Prius? If the answer to that question was "probably not", then the marketing claim was manipulative regardless of whether the technical specifications satisfied a laboratory test. The proportionality test was similarly absent. The Audi tagline "Truth in Engineering" was literally a truth-claim. It was deployed in a context where the engineering was not true.

A separate decision cluster is worth noting: the decisions made by dealer network managers and individual salespeople who sold Clean Diesel vehicles to consumers who asked specifically about environmental performance. Documents disclosed during the US class action litigation show that VW''s US dealer training materials from 2009 to 2014 described Clean Diesel as a premium sustainability offering, used in sales conversations with environmentally conscious buyers who were comparing the Jetta TDI directly to the Toyota Prius. Dealer incentives were structured to reward TDI sales. The marketing materials dealers used at the point of sale — brochures, comparison charts, the "90% cleaner" numeric claims — were the last mile of the fraud, delivered to the specific consumers who most cared about the specific claim that was false. This is where the autonomy test lives in practice: in the conversation between a salesperson and a consumer who is trying to make an informed choice. Dealers did not know the claim was fraudulent. That is legally exculpatory and ethically insufficient. The sales conversation at a US Volkswagen dealership in 2013 was an exercise in informed consent that could not have worked because the information was, by design, wrong.

Data

The financial consequences of Dieselgate are the reason this case is taught in every business school ethics module. As of Volkswagen AG''s 2020 annual report, the company disclosed cumulative costs of €32.0bn directly attributable to the diesel issue. The dollar-equivalent figure most commonly cited — $33bn+ — understates the total by a substantial margin once the costs of model-year 2021-2024 ongoing settlements, EU national enforcement actions, and legal fees are included. By 2023, the running total had passed $39bn.

Category	Amount (USD)	Note
US Department of Justice civil penalty (Clean Air Act)	$14,700,000,000	2016 consent decree — buyback / fix programme
US DoJ criminal plea agreement	$4,300,000,000	January 2017
US class action settlement (consumer)	$10,000,000,000	2016-2017, approximately 475,000 vehicles
EU buyback / recall programme	$5,200,000,000+	2017-2020
German Musterfeststellungsklage settlement	€830,000,000	2020 (approx. $920m)
Australian class action settlement	A$127,000,000	2019
Canadian class action settlement	C$2,100,000,000	2017
Total VW Group disclosed costs (2020 annual report)	€32,000,000,000	Continuing to accrue

Beyond the monetary penalties, the market consequences were severe and instructive. In the five trading days following the EPA Notice of Violation, Volkswagen AG lost €27bn in market capitalisation — roughly 40% of its equity value. US diesel sales, which had peaked at 2.3% of the passenger-car market in 2014, collapsed to below 0.4% by 2018 and never recovered. Volkswagen of America withdrew diesel from its US passenger car lineup entirely in 2017. Audi''s US-market "Truth in Engineering" tagline, which had been in use since 2007, was quietly retired in 2016. The company reverted to its global tagline, "Vorsprung durch Technik" ("Advancement Through Technology"), which had been in use since 1971 and carries no claim about honesty or transparency.

The personnel toll ran into the criminal courts. Martin Winterkorn was indicted in Germany in 2019 on fraud charges; the case was severed from the main Dieselgate criminal trial in 2021 for health reasons. Rupert Stadler, former CEO of Audi, was convicted in June 2023 by a Munich court and received a suspended prison sentence plus a €1.1m fine. Oliver Schmidt was sentenced in December 2017 to seven years'' imprisonment in the US. Six other VW executives were indicted and remain beyond the reach of US extradition in Germany. The long tail of the case — criminal prosecutions, European private litigation, consumer trust damage — continued to accrue through 2025.

Strategically, Volkswagen''s response was the most expensive mid-course correction in automotive history. In September 2016, twelve months after the scandal broke, Winterkorn''s successor Matthias Müller announced "Strategy 2025", later expanded under his successor Herbert Diess into an accelerated electric vehicle programme. Volkswagen committed €60bn of capital expenditure to EV and battery development between 2020 and 2025. The ID.3 and ID.4 electric models, launched in 2020 and 2021, became the foundation of a re-positioned Volkswagen brand promise. The Clean Diesel era became, in the company''s own internal communications, "the crisis that forced the transformation".

The ethical lesson

Dieselgate is the case that most cleanly illustrates the collapse of all three F11 tests simultaneously. It is rare to find a marketing controversy in which the autonomy test, the proportionality test, and the legacy test fail together; Volkswagen achieved it.

The autonomy test asks whether consumers were given the information they needed to make a free choice. The Clean Diesel campaign was built on a specific factual claim — "90% cleaner" NOx emissions — that was false in the environment in which the vehicles actually operated. A consumer who chose a VW Jetta TDI over a Toyota Prius for environmental reasons was making a choice on the basis of information that the company knew to be materially inaccurate. This is not ambiguous marketing puffery about taste or lifestyle. This is a numeric claim about a measurable externality, published in an authoritative tone, that was specifically engineered to pass regulatory tests while failing under real-world use. The failure of autonomy here is not subtle. It is categorical.

The proportionality test asks whether the persuasive techniques are commensurate with the nature of the product and the stakes for the consumer. Volkswagen''s Clean Diesel campaign did not rely on emotional manipulation — it relied on engineering credibility. The Audi "Truth in Engineering" tagline was precisely an appeal to the consumer''s trust in the manufacturer''s technical expertise. When that credibility is the basis of the marketing, and the engineering is fraudulent, the disproportion is total. The consumer has been asked to trust the one thing that the marketer has no grounds to ask them to trust.

The legacy test is the most painful. Would the decisions of 2006-2014 hold up under the norms of 2020-2025? They did not hold up under the norms of 2006 — the Clean Air Act, the EU Euro 5 and Euro 6 standards, and the basic tort law of consumer deception were already in place. The decision to deploy defeat device software was not a failure to anticipate future ethical standards. It was a failure to respect the standards that already existed. The only thing that has changed since 2015 is the enforcement environment. Post-Dieselgate, the EU''s Worldwide Harmonised Light Vehicle Test Procedure (WLTP, introduced 2017) and Real Driving Emissions (RDE, introduced 2017) regimes have made the specific fraud impossible to repeat. The EPA has expanded on-road portable emissions measurement testing. The ACM in the Netherlands and the CMA in the UK have both issued post-Dieselgate guidance on sustainability marketing claims that cite the VW case explicitly.

The broader lesson is about marketing''s relationship with engineering and regulatory colleagues. In most organisations, marketing sits downstream of the product. Marketers sell what engineers build. The Dieselgate lesson is that this division of labour is not a moral safe harbour. When a marketing campaign makes a verifiable factual claim, the marketer''s duty is not merely to pass the claim through from engineering to media. It is to understand the claim well enough to be accountable for it. "The engineers told me so" is not a defence. Deutsch LA did not know the Clean Diesel claims were false; this is a legal defence, but not an ethical one. The agencies and internal marketing teams that amplified "Clean Diesel" between 2008 and 2015 did not exercise the professional scepticism that a mature marketing function owes to its audiences. That is the Dieselgate ethical lesson, and it is the one that most often goes unlearned.

The synthesis

There are two standard readings of Dieselgate, and each captures something important.

The first is the governance reading. On this view, Dieselgate is a story about corporate culture — about how Martin Winterkorn''s confrontational management style, Volkswagen''s opaque family-controlled supervisory board, and a century of German automotive engineering exceptionalism combined to produce an organisation in which inconvenient facts could not travel upward. The solution to Dieselgate, on this reading, is structural: better whistleblowing protections, clearer escalation paths for compliance concerns, separation of the chairman and CEO roles, independent board committees. This is the reading that dominated the Financial Times and the German business press in 2015-2017, and it is the reading that shaped most of VW''s post-crisis governance reform. Its weakness is that it lets marketers off the hook. If the fraud was purely an engineering / governance failure, then the Clean Diesel marketing campaign was simply misled — a victim, not an accomplice.

The second reading is the marketing reading. On this view, Dieselgate is a story about what happens when a marketing narrative gets ahead of the engineering reality and refuses to be corrected. The "90% cleaner" claim created a commercial commitment that the engineering team had to honour somehow. The pressure to deliver on the marketing promise was, itself, part of what produced the defeat device. On this reading, the villain is not just Winterkorn or Liang or Schmidt — it is the sustainability marketing playbook that treats environmental claims as brand-differentiation opportunities rather than verifiable facts. This is the reading that has driven subsequent regulation in the EU (the Green Claims Directive), the Netherlands (the ACM 2023 guidance), and the UK (CMA Green Claims Code). Its weakness is that it can dissolve into a generic anti-marketing critique, in which all claims are suspect and all advertising is manipulation.

The The synthesis holds both in tension. Dieselgate was a governance failure inside Volkswagen AG and a marketing failure inside Volkswagen of America and its agency partners. It was both. The productive resolution is to reject the idea that these are separable. Marketing cannot make a verifiable factual claim about a product without taking responsibility for the claim''s truth. Engineering cannot honour a commercial commitment by cheating a regulatory test. Governance cannot enforce integrity it has not institutionalised. Dieselgate is the case that shows, in full financial detail, what happens when these three functions treat their ethical obligations as someone else''s problem. The $39bn invoice is the price of that evasion. The lesson for marketers is not that they should be humble about engineering claims. It is that they should not sell what they cannot verify, and they should not hide behind the engineers when they are asked to explain why the claim was made.

Sources

• US Environmental Protection Agency (18 September 2015) Notice of Violation to Volkswagen AG, Audi AG, and Volkswagen Group of America, Inc., CAA-HQ-2015-3814.
• US Department of Justice (4 January 2016) United States v. Volkswagen AG, et al., Civil complaint, Eastern District of Michigan.
• US Department of Justice (11 January 2017) Plea Agreement: United States v. Volkswagen AG, Eastern District of Michigan.
• Thompson, G.J., Carder, D.K., Besch, M.C., et al. (May 2014) In-Use Emissions Testing of Light-Duty Diesel Vehicles in the United States, Center for Alternative Fuels, Engines and Emissions, West Virginia University, for the International Council on Clean Transportation.
• Ewing, J. (2017) Faster, Higher, Farther: The Inside Story of the Volkswagen Scandal. W.W. Norton.
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• Winterkorn, M. (23 September 2015) Resignation statement, Volkswagen AG press release.
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• European Parliament, Committee of Inquiry into Emission Measurements in the Automotive Sector (April 2017) Final Report, EMIS committee (A8-0049/2017).
• German Federal Court of Justice (25 May 2020) BGH VI ZR 252/19, the lead German civil case recognising VW''s liability to consumers.
• Landesgericht München II (27 June 2023) Judgment in Staatsanwaltschaft v. Stadler et al., sentencing Rupert Stadler to suspended prison term and €1.1m fine.
• Deutsch LA (2008-2015) Agency case materials and Effie Award submissions for the "Clean Diesel" campaign, archived.
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