The court handling the case hasn't approved a deal, so changes could still be made.
Volkswagen also doesn't have an agreement with the owners of the 3-litre cars who have sued the company or with the Federal Trade Commission, which filed a lawsuit against the company for false advertising.
Both the steering group for the car owners and the FTC are demanding that Volkswagen offer to buy back all of the tainted vehicles, which the carmaker is seeking to avoid, the people said.
Volkswagen's Audi unit, which developed the 3-litre engine and is handling the talks, declined to comment citing confidentiality agreements. The affected models include diesel versions of the VW Touareg, Porsche Cayenne and Audi Q5, Q7 and A8. Spokespeople for EPA and CARB also declined to comment.
A spokesman for the FTC didn't immediately return a call seeking comment.
In addition to the unresolved 3-litre issue, the carmaker is still under criminal investigation in the US and on the hook for outstanding civil claims from several states. It also faces hundreds of investor lawsuits in Germany and is the subject of a criminal probe there as well.
The court decision over 2-litre engines can still be appealed, which has delayed the implementation of Volkswagen's program to buy back or potentially fix those cars. So far, about 75 per cent of owners of those vehicles have registered to participate in the settlement. To avoid additional penalties, the company has a target of getting 85 per cent of those cars off US roads.
In the 3-litre discussions, the two sides have yet to agree on how much Volkswagen should compensate customers to get their vehicles fixed, the people said.
Under the settlement for the smaller vehicles, Volkswagen agreed to pay owners as much as nearly $10,000 to have their cars repaired, while lease-holders will get up to $5,000.