It was revealed VW cheated on EPA emissions tests by programming 2009-2015 diesel vehicles to recognize test conditions the EPA uses. This practice has been going on since the 1990s when sensors gained enough resolution to determine the approximate ambient temperature and transmissions started to share vehicle speed with the engine’s computer.
Most EPA tests do not use the OBDII connector. These tests are performed in a test cell while on a rolling road and are standardized for temperature, time and speed. The VW engineers probably programmed the ECU to look for specific conditions that would only occur in the test cell. If the vehicle detects certain conditions, it engages the “cheat mode” that makes the engine run cleaner.
The EPA does not have the resources to pull and police the code from the vehicle to look for this cheat code. Just like with most scan tool manufacturers and aftermarket parts manufacturers, the EPA the code is more or less encrypted by its proprietary nature. After this latest revelation, there should be a call for standardized code and language for emissions and engine operation. In a perfect world, this data would be shared with scan tool manufacturers.
Why did VW manufacture its cars this way? To meet the EPA emission levels it probably would have meant a direct impact on the longevity of the engine. The smoking gun is nitric oxide or NOx. The EPA claims the offending VWs in “normal mode” produce NOx emissions up to 40 times higher than acceptable levels. NOx levels are connected to exhaust temperatures. Typically, lower temperature exhaust gases have greater NOx levels, and lower exhaust temperatures may also help to extend the life of the engine and turbo charger. It appears VW took the gamble that if they fudged the EPA tests, they could save money on drivetrain warranty claims. But, when it was announced that the fine could be in excess of $37,000 per car ($18 billion for nearly 500,000 vehicles), VW had to fess up to the deception.
EPA and CARB want VW to recall the cars in question so they can be reflashed into compliance to meet mandated emission levels. But I know if I owned one of these vehicles, I would be very hesitant to bring my car to the dealer if it meant that the longevity of the engine could be impacted.
VW is not alone. As stated previously, this EPA emissions test cheat has been around for a long time. It is just VW was caught doing it. Many OEMs have tweaked the engine calibrations for cars in the field to solve problems. GM and Honda have introduced new software to reduce oil consumption on vehicles with cylinder deactivation. The Toyota unintended acceleration recall was partially resolved with a reflash that shut the throttle butterfly if the gas and brake pedal were pushed at the same time.
When the VW story broke, many articles — and even the EPA’s press release — claimed that VW installed a “cheater device.” Many reporters could not believe that vehicle was sophisticated enough that the “cheater device” was nothing more than software.
There is a teachable moment here for shops trying to educate consumers on why vehicle diagnostics with proper scan tools is more important than just swapping parts. It is also a reminder for how reflashing new calibrations can solve problems for vehicles that are out warranty.
Courtesy Underhood Service.