After announcing a recall last June over a rear-impact collision fire hazard, Chrysler is finally preparing to recall nearly 1.6 million 1993-98 Jeep Grand Cherokees and 2002-7 Jeep Liberty S.U.V.'s. The fix the automaker is using to correct the problem – the vehicles’ fuel tanks are exposed to rear impacts – is controversial: Chrysler will install trailer hitches to protect the fuel tanks and reduce the chance of fires caused by rear-impact collisions.

“Chrysler Group has finalized replacement part design and is initiating the tooling process to deliver the required volume,” Chrysler said in a statement Thursday evening. “Launching a safety recall demands complex engineering and close collaboration with the National Highway Traffic Safety Administration well before we accumulate replacement parts. Chrysler Group takes seriously its commitment to customer safety.”

In addition, letters that Chrysler plans to send to owners have been posted on N.H.T.S.A.'s website.

Eric Mayne, the Chrysler spokesman who issued the company’s statement, declined to answer questions about the timing of the recall.

Nathan Naylor, a spokesman for N.H.T.S.A., said in a telephone interview that the investigation into Chrysler’s remedy was continuing.