Consumer Reports is suspending its recommendation of the Audi A7 TDI and Volkswagen Touareg TDI. The move comes after the Environmental Protection Agency said the cars used software, called “defeat devices,” to cheat on emissions tests.

The EPA cited six 2014-2016 models fitted with 3.0-liter V6 diesel engines from Audi, Porsche, and Volkswagen, all owned by Volkswagen AG, as not complying with emissions regulations.

The other four models—Audi A6, A8/A8L, and Q5 and Porsche Cayenne—were not tested by Consumer Reports in diesel form. We do not place recommended ratings on cars we haven’t tested so there’s no change in the status of those models. (Of those, the Audi A6 and Q5, and the Porsche Cayenne are recommended with gas engines.)

To earn our recommendation, vehicles must perform well in our testing; have average or better reliability; and perform adequately if they’re included in crash tests conducted by the Insurance Institute for Highway Safety or the National Highway Traffic Safety Administration.

VW has yet to say how it will fix the emissions issue on these cars, so there is no way to speculate if any corrective action could hurt fuel economy and performance. That means we can’t say if our past test results will be applicable to the revised cars.

The EPA says the defeat device software optimizes emissions performance during laboratory testing, while producing a multiple of allowable nitrogen oxide emissions when driven in the real world; nitrogen oxides are a contributor to ground-level ozone and fine particulate matter—sources for health concerns.

Volkswagen has denied these latest allegations, stating that it didn’t install software to alter emissions to cheat testing. 

In September, the EPA found that VW had installed defeat device software in the 2.0-liter diesel engines used by certain Audi and Volkswagen models. VW admitted it had used the software in those models.

Consumer Reports in September suspended its recommendation of the Jetta and Passat diesels.

Audi, Porsche, and Volkswagen dealers have been directed by VW to stop selling new or certified pre-owned diesel models. Note that the EPA says the vehicles named in its allegations are legal and safe to drive.

Our advice for used car shoppers is to wait on buying the suspect Audi, Porsche, and Volkswagen diesel models until the EPA investigation is complete—and the impact of any corrective measures has been determined.