Volkswagen must move quickly to recall and refit models rigged to pass U.S. emissions tests to limit the long-term impact to its reputation, dealers and consumer protection bodies say.
"To regain confidence, Volkswagen needs to indemnify any consumers affected by damage," Klaus Mueller, head of the Federation of German Consumer Organizations, said in a statement.
"The company must either retrofit all affected vehicles or give the affected individuals the right to retrofitting."
The German group has set aside 6.5 billion euros ($7.3 billion) to help cover the costs of the crisis and said that 11 million of its cars could be affected worldwide. However, it has not yet ordered a recall or said which models are involved.
Lawyers have already brought class actions on behalf of scores of car owners in the United States.
Ernst-Robert Nouvertne, who owns VW dealerships in the German town of Solingen, said how quickly VW refitted affected cars would be critical to reassuring customers, adding that several people had called to ask for information.
"Customers are unsettled. It won't just pass us by without problems. Some customers could switch to a petrol car," he said, but noted Volkswagen should be shielded by the loyalty of its customers, at least in its home country.
Sven Rothluebbers wrote on Volkswagen's German Facebook page: "VW must be held fully accountable, but please do not forget that Volkswagen has served Germany with great cars, jobs, social commitment and more the past 70 years!"
Steve Young, managing director of auto industry research firm ICDP, said the experience of previous car recalls by other brands showed it could actually bring dealerships more business.
Young noted how Toyota Motor Corp had recalled millions of vehicles from 2009 due to some customers' complaints that their cars were unintendedly accelerating.
"It depends on how well they manage the process... in the case of the Toyota recall in the U.S., Toyota dealers were able to reconnect with customers," he said.
"If the dealer handles it well, they could help customers use the compensation to switch into petrol and sell their fixed diesel model to somebody who knows what they are getting."
Price trumps environment concerns?
However, many dealers are still in the dark.
A women at the reception desk of a VW dealership in Frankfurt, who declined to give her name, said she had received many queries from diesel car drivers.
"But we haven't got the ultimate answer because we haven't got much information from Volkswagen," she said.
In France, a Volkswagen spokesman said the firm is planning to write to their clients to tell them current models covered by the European Union's Euro 6 emissions standards are not affected, so people who have recently ordered a vehicle should be reassured.
He said clients would be informed as soon as investigations show which vehicles are involved.
In a Swedish Volkswagen Golf chat room, consumers were discussing whether or not it will be possible to cancel recent orders, with one person saying he had been planning to buy one of the hatchbacks, but decided never to buy VW again due to the scandal.
A spokesman for the Swedish Automobile Association Motormannen said emissions concerns were becoming increasingly important for car consumers.
"People want to contribute to a better environment when they're buying a car. Consumers now feel deceived," he said.
Tim Pollard, executive editor of Britain's Car Magazine, agreed: "The actual topic of emissions is a bit of a dry topic, but they (consumers) do understand that it affects the tax they pay and the amount of money in their pocket."
But Ansgar Klein, head of the German Association of Independent Dealerships, does not expect a lasting impact.
"The Golf has not got worse. I don't think prices will fall as a result," he said. "Most drivers care more about fuel consumption than emissions. The scandal has not affected trust in VW cars, although trust in the company has suffered."
Dariusz Balcerzyk from the Automotive Market Research Institute Samar in Warsaw said the same was true in Poland.
"For Poles this is not really that much of an issue. For a Polish customer, it is still the price that matters most, followed by the car's brand," he said.