National auto experts meeting in Brussels Wednesday recommended an EU-wide block on the sale of Mercedes cars produced in breach of single-market rules.
The conclusions drawn by officials from the 28 European Union member states hit German constructor Daimler hard, after the European Commission already backed France in a row over standards limiting air conditioning coolant to a type deemed more environment-friendly.
A statement issued by the Commission said the member-state experts "acknowledged that...corrective measures shall be taken to bring the vehicles in conformity including the withdrawal of those non-conform vehicles already sold on the market, as it has already been done by a member state."
The officials emphasised the need for "full respect" of the EU legal framework.
Daimler will now struggle to gain market access for certain A, B and CLA-class models made since the industry-agreed coolant change.
Daimler stuck to an older coolant, claiming studies showed that the new gas catches fire more easily and puts cars at a greater risk of explosion in case of a crash.
Germany has until August 20 to answer queries on safety and other aspects from the European Commission and avoid potential legal action, having won a temporary national reprieve from German authorities.