Scania claims to be sorted for Euro 6 - as evidence of deep concern over emissions rules emerged elsewhere in the industry.
MAN and other rivals have asked Scania for access to combustion and fuel injection technology that it has developed with Cummins.
Meanwhile, Stefano Chmielewski, CEO at Renault Trucks, has called for the EU to allow truck makers to share knowledge to a greater extent and for research and development grants for the truck industry.
And his boss, Gothenburg-based Volvo Group CEO Leif Johansson, is urging progress on fuel alternatives to diesel.
Europe needs to find out which are the best in terms of total CO2 production and costs, then go ahead with development of the technology and infrastructure, he says.