DETROIT (AP) — The U.S. government's auto safety agency has opened an investigation into a Ford recall for gasoline leaks from cracked fuel injectors that can cause engine fires, saying in documents that the remedy doesn't fix the leaks.

The National Highway Traffic Safety Administration said in the documents posted Friday on its website that the probe will "evaluate the adequacy and safety consequences of the remedy" that Ford specifies in the recall.

The agency moved with unusual speed, posting documents detailing the "recall query" just two days after the recall was made public.

The recall covers nearly 43,000 Ford Bronco Sport SUVs from the 2022 and 2023 model years, and Escape SUVs from 2022. All have 1.5-liter engines.

NHTSA said that fuel injectors can crack, causing gasoline or vapors to leak at a high rate onto hot surfaces in the engine compartment.

The Associated Press reported Wednesday that Ford's remedy for the leaks is installation of a drain tube to send the gas away from hot surfaces, and a software update to detect a pressure drop in the fuel injection system. If that happens, the software will disable the high pressure fuel pump, reduce engine power and cut temperatures in the engine compartment. Owners also will get a "seek service" message.

But the safety agency said that Ford's fix lets fuel drain from a cylinder head hole to the ground below the vehicles. "The recall remedy does not include replacement of the cracked fuel injector," the agency said.

Ford said Friday it is working with NHTSA on the investigation.

The company said in documents that it has reports of five under-hood fires and 14 warranty replacements of fuel injectors, but no reports of crashes or injuries.

In an email on Wednesday, Ford said it is not replacing fuel injectors because it is confident the recall repairs "will prevent the failure from occurring and protect the customer." The new software triggers a dashboard warning light and allows customers to drive to a safe location, stop the vehicle and arrange for service, the company said. NHTSA documents filed by Ford say the problem happens only in about 1% of the SUVs.

The company also said it will extend warranty coverage for cracked fuel injectors, so owners who experience the problem will get replacements. Ford said repairs are already available, and details of the extended warranty will be available in June.

Ford said the recall is an extension of a 2022 recall for the same problem. The repair has already been tested on vehicles involved in the previous recall, and Ford said it's not aware of any problems.

The company also said it isn't recommending that the SUVs be parked only outdoors because there's no evidence that fires happen when vehicles are parked and the engines are off.

NHTSA said in documents that in the 2022 recall, which covered nearly 522,000 Bronco Sports and Escapes, Ford had the same remedy as the latest recall.

Michael Brooks, executive director of the nonprofit Center for Auto Safety, called Ford's remedy for the fuel leaks a "Band-aid type recall" and said the company is trying to avoid the cost of repairing the fuel injectors.