It was brought by US owners of pickup trucks and SUVs whose claimed their frames could rust through.
The proposed settlement covers 1.5 million Tacoma compact pickups, Tundra full-size pickups and Sequoia SUVs.
Court papers alleged that the vehicles had received inadequate rust protection,  and that corrosion could jeopardise their structural integrity.
Lawyers for the plaintiffs estimated the cost of frame replacements at about $3.375bn.
That was based on a cost of about $15,000 per vehicle and inspection costs of about $90m, at $60 per vehicle.
The Japanese carmaker Toyota admitted no liability or wrongdoing in the proposed settlement.
"We want our customers to have a great ownership experience, so we are pleased to resolve this litigation in a way that benefits them and demonstrates that we stand behind the quality and reliability of our vehicles," Toyota said in a statement.
Under the terms of the agreement, Toyota will inspect the vehicles for 12 years from the day they were first sold or leased in order to ascertain if frames need to be replaced at company expense.
They will also reimburse owners who previously paid for frame replacement.
The settlement covers Tacoma trucks from the model years 2005 to 2010, Sequoias from 2005 to 2008 and Tundras from the 2007 and 2008 model years.
The world's biggest carmaker, Toyota,  has agreed to settle a US Federal class action for up to $3.4bn (Â£2.7bn).