As the Volkswagen emissions certification mess continues to unwind, our “Talking Cars With Consumer Reports” video podcast takes a look at the implications for consumers.

VW has admitted to circumventing the emissions control system in about 482,000 diesel vehicles sold in the United States since 2008 with the 2.0-liter TDI engine. An inevitable recall to make these vehicles emissions-legal may have effects on the reliability, performance, and fuel economy of these cars, and there are questions about potential diminished resale value because of TDI's tarnished reputation.

Much of the outrage stems from what turned out to be deceptive advertising. Volkswagen promoted their diesel technology as being "clean diesel," an alternative to gasoline-powered hybrids for the environmentally conscious.

VW was able to cheat because certification tests are conducted on a dynamometer, much like a treadmill for cars. Since the other wheels aren't turning, the car's stability control would be triggered. To circumvent this problem, “dyno mode” programming was added, intended to be used only during the test. Once the test is complete and the car is restarted, the car reverts to its normal function where it has been discovered that nitrogen oxide levels increased by 10 to 40 times the federal standard, according to the EPA.

Right now, it's difficult to determine what changes would be required by a recall in order to make the cars compliant. It could range from a software update—which is more likely to work on newer TDIs with urea-injection systems—to adding expensive and bulky urea-injection systems to the vehicles that don't have them.

For now, Consumer Reports has suspended its “recommended” Rating of two VW vehicles: the Jetta diesel and Passat diesel. We currently own both of these vehicles in our test fleet, as well as a Golf SportWagen TDI. Consumer Reports will re-test these vehicles once a recall repair has been performed to assess whether the fix has adversely affected performance or fuel economy.

Finally, in this show, we discuss the future of diesel-powered cars in the United States. No question, the VW scandal is dealing a tough blow to diesel's reputation. This set back follows multiple manufacturers, including Honda, Mazda, and Subaru announcing they would bring diesels here, only to scuttle their plans. At a time when gasoline-powered engines are making tremendous efficiency gains, diesel is in a fragile position. We put this in perspective in our latest show.  

As with the other Taking Cars, this episode is also available free through the iTunes Store. Subscribe to the video or audio. You'll also find the video on YouTube.

Share your comments on this show below, and let us know if you need any advice for choosing a car.

Mark Rechtin, Tom Mutchler, and Jake Fisher
Mark Rechtin, Tom Mutchler, and Jake Fisher