The news report aired this week on VRT, Belgium's Flemish-language national broadcaster, claiming that Opel is secretly upgrading the software in its 2014 Zafira people movers when they're brought in for service.
Luc Pauwels, the reporter who compiled the report, caught wind of these allegations when he brought his Astra hatchback in for a software upgrade at the request of Opel.
One claimed that Opel has been upgrading software on its 2014 Opel Zafiras with 1.6-litre turbo-diesel engines in order to reduce NOx (oxides of nitrogen) output since around the time news of the dieselgate saga broke.
To investigate those claims, VRT enlisted the help of Thomas More University and British firm Emissions Analytics to measure the tailpipe output of two pre- and post-upgrade Zafiras.
Prior to being serviced, one Zafira emitted 416mg/km of NOx, while the other chugged out 743mg/km, well above the stated EU limit of 80mg/km.
After the service, and the alleged engine software upgrade, the first people mover sent out just 223mg/km, while the second scored even better with just 199mg/km.
General Motors has vigorously denied the claims by VRT, telling The Financial Times that it has been the subject of "false accusations".
The car maker went on to say: "Opel clearly rejects the claim of VRT News that Opel dealers have been modifying software in the Zafira Tourer 1.6 diesel which changes the emission behavior of these vehicles. The mentioned service update ... has nothing to do with changing emission levels."
Opel also claimed that it doesn't use any software to cheat its way past emissions testing and that it has already discussed the software update with the German motoring authorities.