How Automakers Cheat Emissions Tests (And Get Caught)

Introduction

The automotive industry has long been under scrutiny for its environmental impact, particularly concerning harmful emissions. Governments worldwide have implemented strict emissions testing protocols to ensure vehicles meet environmental standards. However, some automakers have resorted to deceptive practices to bypass these regulations—only to face massive scandals, legal repercussions, and reputational damage when caught.

This article explores the various ways automakers cheat emissions tests, the mechanisms behind these deceptions, and how regulators and whistleblowers uncover the truth.

1. The Basics of Emissions Testing

Before delving into how automakers manipulate tests, it’s essential to understand how emissions testing works. Regulatory bodies, such as the Environmental Protection Agency (EPA) in the U.S. and the European Commission in the EU, require vehicles to undergo laboratory tests to measure pollutants like:

• Nitrogen Oxides (NOx) – Linked to smog and respiratory diseases
• Carbon Monoxide (CO) – A poisonous gas
• Particulate Matter (PM) – Tiny particles that harm lungs
• Carbon Dioxide (CO₂) – A greenhouse gas contributing to climate change

These tests are conducted under controlled conditions, typically on a dynamometer (a treadmill for cars), where vehicles follow a standardized driving cycle.

The Problem: Real-World vs. Lab Conditions

The primary loophole automakers exploit is the discrepancy between lab conditions and real-world driving. Since tests follow a predictable pattern, manufacturers can optimize engines to perform well only under these specific conditions—while emitting far more pollutants in everyday driving.

2. How Automakers Cheat Emissions Tests

Automakers have employed several sophisticated (and sometimes blatant) methods to deceive regulators. Here are the most common tactics:

A. “Defeat Devices” – The Volkswagen Scandal

The most infamous case of emissions cheating was Volkswagen’s “Dieselgate” scandal in 2015. The company installed software-based defeat devices in millions of diesel vehicles worldwide.

• How It Worked:

  • The software detected when the car was undergoing an emissions test (based on steering inputs, speed patterns, and lack of wheel movement).
  • During the test, the engine would switch to a low-emissions mode, reducing performance but passing regulatory checks.
  • In real-world driving, the system would disable emissions controls, boosting power and fuel efficiency while emitting up to 40 times the legal NOx limits.

• The Fallout:

  • VW faced $30+ billion in fines, recalls, and settlements.
  • Several executives were criminally charged.
  • The scandal tarnished diesel’s reputation, accelerating the shift toward electric vehicles.

B. “Thermal Window” Exploitation – Fiat Chrysler & Others

Some automakers exploit thermal window strategies—where emissions controls are only active within a narrow temperature range.

• How It Works:

  • Emissions systems (like Selective Catalytic Reduction for NOx) are programmed to shut off in cold or hot weather, claiming engine protection.
  • Since lab tests are conducted at moderate temperatures, the vehicle passes.
  • In reality, the emissions controls are disabled most of the time, leading to excessive pollution.

• Notable Cases:

  • Fiat Chrysler (2017) – Accused of using undeclared software to disable emissions controls.
  • Daimler (2019) – Fined $1.5 billion for similar thermal window manipulations.

C. “Cycle Beating” – Adjusting Engine Parameters for the Test

Another method is cycle beating, where automakers tweak engine calibration to perform optimally only during the test cycle.

• Examples:

  • Gearshift Manipulation – Some cars detect test conditions and prevent gear shifts that would increase emissions.
  • Overinflated Tires – Reducing rolling resistance artificially lowers CO₂ readings.
  • Disabling Air Conditioning – Since tests often run without AC, some cars detect lab conditions and shut off power-draining systems.

• Who Got Caught?

  • Mitsubishi (2016) – Admitted to falsifying fuel economy data.
  • Renault, Nissan, and PSA Group – Investigated for suspicious emissions patterns.

D. “Hardware Defeat Devices” – Physical Cheating Mechanisms

Beyond software, some manufacturers have used physical modifications to cheat tests:

• Cheat Pipes – Some trucks were found with extra exhaust pipes that bypassed emissions controls when not in testing mode.
• Defeat Chips – Aftermarket devices (often sold as “performance tuners”) disable emissions controls entirely.

3. How Regulators and Whistleblowers Catch the Cheaters

Despite automakers’ sophisticated methods, they often get caught through:

A. Independent Real-World Testing

• Real Driving Emissions (RDE) Tests – Introduced in the EU after Dieselgate, these tests measure pollutants on actual roads rather than in labs.
• Independent Researchers – Groups like ICCT (International Council on Clean Transportation) exposed VW by testing cars on the road.

B. Whistleblowers and Internal Leaks

• Many scandals begin with engineers or employees reporting unethical practices.

  • Volkswagen’s scandal was partly uncovered by a WVU research team funded by the ICCT.
  • Daimler’s case involved internal documents leaked to authorities.

C. Advanced Detection Software

• Regulators now use machine learning algorithms to detect anomalies between lab and real-world emissions.
• OBD (On-Board Diagnostics) Monitoring – Authorities can remotely check if emissions systems are functioning properly.

4. The Consequences of Emissions Cheating

When caught, automakers face:

• Massive Fines – VW ($30B+), Daimler ($1.5B), Fiat Chrysler ($800M).
• Criminal Charges – Executives have been imprisoned (e.g., VW’s Oliver Schmidt).
• Reputation Damage – Consumer trust erodes, impacting sales long-term.
• Stricter Regulations – Governments impose tougher testing standards.

5. The Future: Can Automakers Be Trusted?

While regulations are tightening, the temptation to cheat remains—especially as electric vehicles (EVs) reduce the need for combustion engine testing. However, with AI-powered monitoring, whistleblower protections, and real-world testing, it’s becoming harder for automakers to deceive regulators.

Key Takeaways:

✅ Emissions cheating is often done through software tricks, thermal loopholes, or hardware modifications.
✅ Real-world testing and whistleblowers are critical in uncovering fraud.
✅ The consequences are severe—fines, lawsuits, and reputational ruin.
✅ The industry is moving toward transparency, but vigilance remains necessary.

Conclusion

The history of emissions cheating reveals a troubling pattern of corporate deception—but also the power of regulation, technology, and ethical whistleblowing in holding automakers accountable. As the world shifts toward cleaner transportation, the lessons from these scandals must ensure that cheating becomes a relic of the past.

Will automakers learn? Or will new forms of deception emerge? Only time—and stricter oversight—will tell.