FILE PHOTO: A U.S. flag flutters in the wind above a Volkswagen dealership in Carlsbad, California, U.S. on May 2, 2016. REUTERS/Mike Blake/File Photo

BERLIN (Reuters) - Volkswagen VOWG_p.DE said on Friday it had stopped delivering the T6 multivan to dealers after detecting that the diesel model emitted excessive nitrogen oxide levels and had reported the findings to Germany's automotive watchdog (KBA).

Earlier on Friday German magazine Der Spiegel, without identifying the source of its information, reported that VW tests had shown that T6 toxic nitrogen oxide emissions in part significantly exceeded legal limits as VW had set an emissions-related so-called “adjustment factor” too low when seeking KBA approval for the model.

“VW commercial vehicles is looking into signs that certain technical data... cannot be fully confirmed” by reviews of the T6 model’s actual and planned emission levels, a spokesman for VW’s van division said.

The spokesman ruled out the possibility that the engine management software was the cause of the “uncertainties”, and said VW had agreed with the KBA to run further tests.

More than two years ago, VW admitted to U.S. authorities that it had used a “defeat device” - or software - in diesel engines that could detect when they were being tested and change the performance accordingly to improve emissions results.

The VW commercial vehicles division’s Amarok pick-up truck and box-type Caddy model were implicated in the carmaker’s “dieselgate” scandal as they also carried the engine at the center of the manipulations, codenamed EA 189.

The van division spokesman did not comment on engine types, the number of vehicles affected or when the models in question were built. The KBA had no immediate comment on the matter.