There's no fix yet for the over 600,000 vehicles in the US affected by Volkswagen's diesel emissions scandal, even though months have passed since the Environmental Protection Agency (EPA) first discovered discrepancies in the German automaker's reports. That's because regulators have yet to approve Volkswagen's proposed solution, which includes a simple software fix for some 100,000 3-liter diesels.

Now, Volkswagen reportedly has a new solution up its sleeve. German newspaper Bild am Sonntag reports that the company has devised a new catalyst for 430,000 of the affected vehicles that use first-generation (EA189) 2.0-liter TDI diesel engines. The report doesn't indicate its source, and its not clear if the repair would require a complete replacement of the catalytic converter, or just a swap of the catalyst inside the unit. A Reuters source and the Financial Times backed up the report. Catalytic converters use a chemical reaction to capture some toxins and convert them to less-harmful substances as they pass through the exhaust system.

News of the emissions fix comes just days before Volkswagen CEO Matthias Müller arrives in Washington, DC on Wednesday to meet with EPA administrator Gina McCarthy for the first time. The sit-down reportedly comes at the automaker's request, as it seeks to resolve differences with the regulatory agency. On Thursday, McCarthy said, "We've been having a large amount of technical discussions back and forth with Volkswagen." She added, "At this point, we haven't identified a satisfactory way forward, but those discussions are going to continue. We are really anxious to find a way for that company to get into compliance, and we're not there yet."

The EPA and the California Air Resources Board (CARB) received initial repair plans from Volkswagen on November 20th. In December, CARB pushed back its deadline to approve or deny those plans until next week. Volkswagen's new fix, centering on the catalytic converter, may indicate that the carmaker expects the regulatory bodies to reject its initial plans. The US regulators have stricter requirements than their counterparts in Europe, which approved Volkswagen's repair plans last month.

The outcome of Wednesday's meeting between Müller and McCarthy may be crucial for Volkswagen. A separate report from German newspaper Süddeutsche Zeitung last week indicated that the company may have to buy back over 100,000 affected vehicles in the US, or offer owners replacement vehicles at a major discount. That comes on top of a new Department of Justice lawsuit that could cost Volkswagen at least $1.65 billion in fines. And that amount could top out at a massive $48 billion, according to reports.