Earlier today, the Environmental Protection Agency took the unusual action of issuing a motor vehicle recall for nearly 500,000 Volkswagen and Audi sedans that used software to circumvent emissions tests. In light of this development, our colleagues at Consumer Reports have suspended their rating for two of the cars involved in the recall.

CR had previously given a “Recommended” rating to the diesel versions of both the VW Jetta and Passat.

“These recommendations will be suspended until Consumer Reports can re-test these vehicles with a recall repair performed,” reads at a statement from the publication. “Once the emissions systems are functioning properly, we will assess whether the repair has adversely affected performance or fuel economy.”

In addition to the Passat and Jetta, recalls for issued for the diesel editions of the VW Beetle and the Audi 3.

The EPA determined, following an independent analysis by researchers at West Virginia University, that the automaker intentionally installed “defeat device” software in 482,000 diesel 4-cylinder vehicles between model years 2009 and 2015 as a way to evade emissions standards for certain pollutants.

According to agency, the “sophisticated software algorithm” in the vehicles is programmed to detect when the car is undergoing official emissions testing. When it determines that a test is being performed, the vehicle’s full emissions control system will be deployed.

But the EPA says that when a test is not being performed, these cars “emit nitrogen oxides, or NOx, at up to 40 times the standard.”

“Using a defeat device in cars to evade clean air standards is illegal and a threat to public health,” Cynthia Giles, Assistant Administrator for the Office of Enforcement and Compliance Assurance, said in a statement.

An EPA official confirmed to Reuters that Volkswagen could face a penalty of up to $18 billion if it has to pay the maximum fine of $37,500 on each of the non-compliant vehicles.

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